In this second part of the tutorial we will create Android Application to consume API’s we created in previous part.

Some changes and features in our Android Application,

-> Use Retrofit for networking along with RxJava

-> Neat and Simple Material Design

-> Use Java 8 lambda functions

-> Use Fragments instead of multiple Activities

Google’s new Jack compiler has become stable and much faster over the past few months. We can now completely switch to the Jack compiler. Only disadvantage is, it does not support Instant Run now.Also I am using the latest version of Android Studio which was released a few days back.

RxJava is a trending Reactive programming Java framework. It can be used to create event based asynchronous programs. In this tutorial we will use RxJava for performing Retrofit network operations.

You can download the complete project as zip or fork from our Github repository.

Here I have created a Android Studio project with package com.learn2crack also Activity as MainActivity and layout as activity_main.

Note : Make sure you have downloaded the latest Android Support Repository from SDK Manager.

In the app’s build.gradle add the following snippet to the defaultConfig section to enable Jack,

jackOptions {
enabled true
}

Then we need to set the Java version to 8 for Jack and Lambda functions to work. Add the snippet to the android section,

compileOptions {
sourceCompatibility JavaVersion.VERSION_1_8
targetCompatibility JavaVersion.VERSION_1_8
}

The additional dependencies we require are,

compile 'com.android.support:design:24.2.1'
compile 'com.android.support:cardview-v7:24.2.1'

compile 'com.squareup.retrofit2:retrofit:2.1.0'
compile 'com.squareup.retrofit2:converter-gson:2.1.0'
compile 'com.squareup.retrofit2:adapter-rxjava:2.1.0'
compile 'io.reactivex:rxjava:1.2.0'
compile 'io.reactivex:rxandroid:1.2.1'

We have added the dependencies for RxJava, Retrofit, CardView and Design Support Library.

The complete build.grade,

apply plugin: 'com.android.application'

android {
    compileSdkVersion 24
    buildToolsVersion "24.0.2"
    defaultConfig {
        applicationId "com.learn2crack"
        minSdkVersion 19
        targetSdkVersion 24
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"

        jackOptions {
            enabled true
        }
    }

    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile 'com.android.support:appcompat-v7:24.2.1'
    compile 'com.android.support:design:24.2.1'
    compile 'com.android.support:cardview-v7:24.2.1'

    compile 'com.squareup.retrofit2:retrofit:2.1.0'
    compile 'com.squareup.retrofit2:converter-gson:2.1.0'
    compile 'com.squareup.retrofit2:adapter-rxjava:2.1.0'
    compile 'io.reactivex:rxjava:1.2.0'
    compile 'io.reactivex:rxandroid:1.2.1'
    testCompile 'junit:junit:4.12'
}

We need permission to access Internet. Add the following code for Internet permission.

<uses-permission android:name="android.permission.INTERNET" />

We need to define the colors, dimens and styles to use in out layout.

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="colorPrimary">#3F51B5</color>
    <color name="colorPrimaryDark">#303F9F</color>
    <color name="colorAccent">#FF4081</color>
    <color name="colorDarkGrey">#455A64</color>
</resources>

<resources>
    <dimen name="activity_horizontal_margin">16dp</dimen>
    <dimen name="activity_vertical_margin">16dp</dimen>
    <dimen name="child_margin_top">24dp</dimen>
    <dimen name="logo_height">80dp</dimen>
    <dimen name="button_padding">48dp</dimen>
    <dimen name="button_margin">24dp</dimen>
    <dimen name="card_padding">16dp</dimen>
    <dimen name="card_items_margin">8dp</dimen>
</resources>

<resources>
    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>
    </style>

    <style name="AppTheme.LoginRegister" parent="AppTheme">
        <item name="windowActionBar">false</item>
        <item name="windowNoTitle">true</item>
        <item name="android:windowBackground">@color/colorPrimary</item>
        <item name="colorControlNormal">@android:color/white</item>
        <item name="colorControlHighlight">@android:color/white</item>
        <item name="colorControlActivated">@android:color/white</item>
        <item name="colorButtonNormal">@color/colorAccent</item>
        <item name="android:textColor">@android:color/white</item>
        <item name="android:textColorPrimary">@android:color/white</item>
        <item name="android:editTextColor">@android:color/white</item>
    </style>

    <style name="AppTheme.Profile" parent="AppTheme">
        <item name="android:windowBackground">@color/colorDarkGrey</item>
        <item name="colorButtonNormal">@color/colorAccent</item>
        <item name="android:textColorPrimary">@android:color/white</item>
    </style>

    <style name="AppTheme.Dialog" parent="Theme.AppCompat.Light.Dialog">
        <item name="colorPrimary">@android:color/black</item>
    </style>
</resources>

Our main layout activity_main has a FrameLayout which acts as a placeholder for Fragments.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.learn2crack.MainActivity">

    <FrameLayout
        android:id="@+id/fragmentFrame"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>
</RelativeLayout>

Our login screen layout has EditText input fields for Email and Password along with Button for login. It also has TextViews for Register and Forgot password.

<?xml version="1.0" encoding="utf-8"?>

<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fillViewport="true">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <RelativeLayout
            android:orientation="vertical"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_margin="@dimen/activity_vertical_margin">

            <ImageView
                android:id="@+id/img_logo"
                android:layout_width="wrap_content"
                android:layout_height="@dimen/logo_height"
                android:layout_centerHorizontal="true"
                android:src="@drawable/logo"/>

            <android.support.design.widget.TextInputLayout
                android:id="@+id/ti_email"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_below="@+id/img_logo"
                android:layout_marginTop="@dimen/child_margin_top">

                <EditText
                    android:id="@+id/et_email"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:drawableRight="@drawable/ic_email"
                    android:hint="Email"
                    android:inputType="textEmailAddress" />

            </android.support.design.widget.TextInputLayout>

            <android.support.design.widget.TextInputLayout
                android:id="@+id/ti_password"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_below="@+id/ti_email"
                android:layout_marginTop="@dimen/child_margin_top"
                app:passwordToggleEnabled="true"
                app:passwordToggleTint="@android:color/white">

                <EditText
                    android:id="@+id/et_password"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:hint="Password"
                    android:inputType="textPassword" />

            </android.support.design.widget.TextInputLayout>

            <Button
                android:id="@+id/btn_login"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_below="@+id/ti_password"
                android:layout_marginTop="@dimen/button_margin"
                android:drawableRight="@drawable/ic_arrow_forward"
                android:paddingLeft="@dimen/button_padding"
                android:text="Login" />

            <TextView
                android:id="@+id/tv_register"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_below="@+id/btn_login"
                android:layout_marginTop="@dimen/button_margin"
                android:text="Not Registered ? Register Now !"
                android:textAlignment="center" />

            <TextView
                android:id="@+id/tv_forgot_password"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_below="@+id/tv_register"
                android:layout_marginTop="@dimen/button_margin"
                android:text="Forgot Password ?"
                android:textAlignment="center" />

            <ProgressBar
                android:id="@+id/progress"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_below="@+id/tv_forgot_password"
                android:layout_centerHorizontal="true"
                android:layout_marginTop="@dimen/button_margin"
                android:layout_marginBottom="@dimen/button_margin"
                android:visibility="gone"/>

        </RelativeLayout>
    </LinearLayout>
</ScrollView>

Similarly our register screen has additional input field for name.

<?xml version="1.0" encoding="utf-8"?>

<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fillViewport="true">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <RelativeLayout
            android:orientation="vertical"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_margin="@dimen/activity_vertical_margin">

            <ImageView
                android:id="@+id/img_logo"
                android:layout_width="wrap_content"
                android:layout_height="@dimen/logo_height"
                android:layout_centerHorizontal="true"
                android:src="@drawable/logo"/>

            <android.support.design.widget.TextInputLayout
                android:id="@+id/ti_name"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_below="@+id/img_logo"
                android:layout_marginTop="@dimen/child_margin_top">

                <EditText
                    android:id="@+id/et_name"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:drawableRight="@drawable/ic_person"
                    android:hint="Name"
                    android:inputType="text" />

            </android.support.design.widget.TextInputLayout>

            <android.support.design.widget.TextInputLayout
                android:id="@+id/ti_email"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_below="@+id/ti_name"
                android:layout_marginTop="@dimen/child_margin_top">

                <EditText
                    android:id="@+id/et_email"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:drawableRight="@drawable/ic_email"
                    android:hint="Email"
                    android:inputType="textEmailAddress" />

            </android.support.design.widget.TextInputLayout>

            <android.support.design.widget.TextInputLayout
                android:id="@+id/ti_password"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_below="@+id/ti_email"
                android:layout_marginTop="@dimen/child_margin_top"
                app:passwordToggleEnabled="true"
                app:passwordToggleTint="@android:color/white">

                <EditText
                    android:id="@+id/et_password"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:hint="Password"
                    android:inputType="textPassword" />

            </android.support.design.widget.TextInputLayout>

            <Button
                android:id="@+id/btn_register"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_below="@+id/ti_password"
                android:layout_marginTop="@dimen/button_margin"
                android:drawableRight="@drawable/ic_arrow_forward"
                android:paddingLeft="@dimen/button_padding"
                android:text="Register" />

            <TextView
                android:id="@+id/tv_login"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_below="@+id/btn_register"
                android:padding="@dimen/button_margin"
                android:text="Already Registered ? Login Now !"
                android:textAlignment="center" />

            <ProgressBar
                android:id="@+id/progress"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_below="@+id/tv_login"
                android:layout_centerHorizontal="true"
                android:layout_marginBottom="@dimen/button_margin"
                android:visibility="gone"/>

        </RelativeLayout>
    </LinearLayout>
</ScrollView>

Our profile screen has three TextView in a CardView which displays name, email and time at which profile is created. Also it has buttons for Change Password and Logout.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_profile"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.learn2crack.ProfileActivity">

    <ProgressBar
        android:id="@+id/progress"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="@dimen/button_margin" />

    <android.support.v7.widget.CardView
        android:id="@+id/card"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/progress">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_margin="@dimen/card_padding">

            <TextView
                android:id="@+id/tv_name"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerHorizontal="true"
                android:textColor="@android:color/black"
                android:textAppearance="?android:attr/textAppearanceLarge"/>

            <TextView
                android:id="@+id/tv_email"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_below="@+id/tv_name"
                android:layout_marginTop="@dimen/card_items_margin"
                android:layout_centerHorizontal="true"
                android:textAppearance="?android:attr/textAppearanceMedium"/>

            <TextView
                android:id="@+id/tv_date"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_below="@+id/tv_email"
                android:layout_marginTop="@dimen/card_items_margin"
                android:layout_centerHorizontal="true"/>
        </RelativeLayout>
    </android.support.v7.widget.CardView>

    <Button
        android:id="@+id/btn_change_password"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/card"
        android:layout_marginTop="@dimen/button_margin"
        android:drawableRight="@drawable/ic_lock"
        android:paddingLeft="@dimen/button_padding"
        android:text="Change Password" />

    <Button
        android:id="@+id/btn_logout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/btn_change_password"
        android:layout_marginTop="@dimen/button_margin"
        android:drawableRight="@drawable/ic_exit"
        android:paddingLeft="@dimen/button_padding"
        android:text="Logout" />

</RelativeLayout>

Change password layout is displayed as a DialogFragment which has two input fields for old and new password and buttons. It also has a TextView to display messages.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="@dimen/activity_horizontal_margin">

    <android.support.design.widget.TextInputLayout
        android:id="@+id/ti_old_password"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="@dimen/child_margin_top"
        app:passwordToggleEnabled="true"
        app:passwordToggleTint="@color/colorAccent">

        <EditText
            android:id="@+id/et_old_password"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="Old Password"
            android:inputType="textPassword"
            android:textColor="@color/colorAccent"/>

    </android.support.design.widget.TextInputLayout>

    <android.support.design.widget.TextInputLayout
        android:id="@+id/ti_new_password"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/ti_old_password"
        android:layout_marginTop="@dimen/child_margin_top"
        app:passwordToggleEnabled="true"
        app:passwordToggleTint="@color/colorAccent">

        <EditText
            android:id="@+id/et_new_password"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="New Password"
            android:inputType="textPassword"
            android:textColor="@color/colorAccent"/>

    </android.support.design.widget.TextInputLayout>

    <Button
        android:id="@+id/btn_change_password"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/ti_new_password"
        android:layout_alignParentLeft="true"
        android:text="Change Password"
        android:layout_marginTop="@dimen/button_margin"
        style="@style/Widget.AppCompat.Button.Borderless.Colored"/>

    <Button
        android:id="@+id/btn_cancel"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/ti_new_password"
        android:text="Cancel"
        android:layout_alignParentRight="true"
        android:layout_marginTop="@dimen/button_margin"
        style="@style/Widget.AppCompat.Button.Borderless.Colored"/>

    <TextView
        android:id="@+id/tv_message"
        android:visibility="gone"
        android:layout_below="@+id/btn_change_password"
        android:layout_centerHorizontal="true"
        android:textColor="@android:color/holo_red_dark"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <ProgressBar
        style="@style/Base.Widget.AppCompat.ProgressBar"
        android:id="@+id/progress"
        android:visibility="gone"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="@dimen/button_margin"
        android:layout_marginBottom="@dimen/button_margin"
        android:indeterminate="true"
        android:layout_below="@+id/tv_message"/>

</RelativeLayout>

Reset password dialog has input fields for Email, token and password. Initially the two fields were set visibility to Gone. The TextView field is used to display messages.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="@dimen/activity_horizontal_margin"
    android:background="@color/colorDarkGrey">

    <android.support.design.widget.TextInputLayout
        android:id="@+id/ti_email"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="@dimen/child_margin_top">

        <EditText
            android:id="@+id/et_email"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="Email"
            android:drawableRight="@drawable/ic_email"
            android:inputType="textEmailAddress"
            android:textColor="@color/colorAccent"/>

    </android.support.design.widget.TextInputLayout>

    <android.support.design.widget.TextInputLayout
        android:id="@+id/ti_token"
        android:visibility="gone"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/ti_email"
        android:layout_marginTop="@dimen/child_margin_top">

        <EditText
            android:id="@+id/et_token"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="Token"
            android:drawableRight="@drawable/ic_email"
            android:inputType="textEmailAddress"
            android:textColor="@color/colorAccent"/>

    </android.support.design.widget.TextInputLayout>

    <android.support.design.widget.TextInputLayout
        android:id="@+id/ti_password"
        android:visibility="gone"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/ti_token"
        android:layout_marginTop="@dimen/child_margin_top"
        app:passwordToggleTint="@android:color/white">

        <EditText
            android:id="@+id/et_password"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="New Password"
            android:inputType="textPassword"
            android:textColor="@color/colorAccent"/>

    </android.support.design.widget.TextInputLayout>

    <Button
        android:id="@+id/btn_reset_password"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/ti_password"
        android:layout_centerHorizontal="true"
        android:text="Reset Password"
        android:layout_marginTop="@dimen/button_margin"
        style="@style/Widget.AppCompat.Button.Borderless.Colored"/>

    <TextView
        android:id="@+id/tv_message"
        android:visibility="gone"
        android:layout_below="@+id/btn_reset_password"
        android:layout_centerHorizontal="true"
        android:textColor="@android:color/holo_red_dark"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <ProgressBar
        style="@style/Base.Widget.AppCompat.ProgressBar"
        android:id="@+id/progress"
        android:visibility="gone"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="@dimen/button_margin"
        android:layout_marginBottom="@dimen/button_margin"
        android:indeterminate="true"
        android:layout_below="@+id/tv_message"/>

</RelativeLayout>

The image given below shows the exact project structure.

We have two model classes. These classes are present in separate package model. One is the User class which has name, email, password, created_at, newPassword, token as fields.

package com.learn2crack.model;

public class User {

    private String name;
    private String email;
    private String password;
    private String created_at;
    private String newPassword;
    private String token;

    public void setName(String name) {
        this.name = name;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getName() {
        return name;
    }

    public String getEmail() {
        return email;
    }

    public String getCreated_at() {
        return created_at;
    }

    public void setNewPassword(String newPassword) {
        this.newPassword = newPassword;
    }

    public void setToken(String token) {
        this.token = token;
    }
}

The other class is Response which has message and token as fields.

package com.learn2crack.model;

public class Response {

    private String message;
    private String token;

    public String getMessage() {
        return message;
    }

    public String getToken() {
        return token;
    }
}

We have Constants and Validation class present in utils package. The Constants class has Base Url and Token, Email String. If you are testing in emulator use the IP 10.0.2.2 in Base URL. If you are using in a device make sure the device and your PC are in same network and use the IP of your PC.

package com.learn2crack.utils;

public class Constants {

    public static final String BASE_URL = "http://10.0.2.2:8080/api/v1/";
    public static final String TOKEN = "token";
    public static final String EMAIL = "email";
}

Validation class has two static methods for validating fields such as email and name.

package com.learn2crack.utils;

import android.text.TextUtils;
import android.util.Patterns;

public class Validation {

    public static boolean validateFields(String name){

        if (TextUtils.isEmpty(name)) {

            return false;

        } else {

            return true;
        }
    }

    public static boolean validateEmail(String string) {

        if (TextUtils.isEmpty(string) || !Patterns.EMAIL_ADDRESS.matcher(string).matches()) {

            return false;

        } else {

            return  true;
        }
    }
}

All the RESTful endpoints are defined in RetrofitInterface.class which will be called for subsequent operation. Each method returns a RxJava Observable. This Observable can be subscribed by a Observer.

package com.learn2crack.network;

import com.learn2crack.model.Response;
import com.learn2crack.model.User;

import retrofit2.http.Body;
import retrofit2.http.GET;
import retrofit2.http.POST;
import retrofit2.http.PUT;
import retrofit2.http.Path;
import rx.Observable;

public interface RetrofitInterface {

    @POST("users")
    Observable<Response> register(@Body User user);

    @POST("authenticate")
    Observable<Response> login();

    @GET("users/{email}")
    Observable<User> getProfile(@Path("email") String email);

    @PUT("users/{email}")
    Observable<Response> changePassword(@Path("email") String email, @Body User user);

    @POST("users/{email}/password")
    Observable<Response> resetPasswordInit(@Path("email") String email);

    @POST("users/{email}/password")
    Observable<Response> resetPasswordFinish(@Path("email") String email, @Body User user);
}

The NetworkUtil class has three getRetrofit() static methods with three different parameters. The default method without parameters returns RetrofitInterface object. Since we use RxJava with Retrofit we need to add RxJavaCallAdapterFactory object.

The second method takes email and password as parameters. These parameters are combined and encoded to get a Base64 encoded string which is used for Basic Authentication. These string is set to header variable Authorization using OkhttpClient.

The third method takes token as parameter. This is the JSON Web Token. This token is set for the header variable x-access-token.

package com.learn2crack.network;

import android.util.Base64;

import com.learn2crack.utils.Constants;

import okhttp3.OkHttpClient;
import okhttp3.Request;
import retrofit2.Retrofit;
import retrofit2.adapter.rxjava.RxJavaCallAdapterFactory;
import retrofit2.converter.gson.GsonConverterFactory;
import rx.schedulers.Schedulers;

public class NetworkUtil {

    public static RetrofitInterface getRetrofit(){

        RxJavaCallAdapterFactory rxAdapter = RxJavaCallAdapterFactory.createWithScheduler(Schedulers.io());

        return new Retrofit.Builder()
                .baseUrl(Constants.BASE_URL)
                .addCallAdapterFactory(rxAdapter)
                .addConverterFactory(GsonConverterFactory.create())
                .build().create(RetrofitInterface.class);

    }

    public static RetrofitInterface getRetrofit(String email, String password) {

        String credentials = email + ":" + password;
        String basic = "Basic " + Base64.encodeToString(credentials.getBytes(),Base64.NO_WRAP);
        OkHttpClient.Builder httpClient = new OkHttpClient.Builder();

        httpClient.addInterceptor(chain -> {

            Request original = chain.request();
            Request.Builder builder = original.newBuilder()
                    .addHeader("Authorization", basic)
                    .method(original.method(),original.body());
            return  chain.proceed(builder.build());

        });

        RxJavaCallAdapterFactory rxAdapter = RxJavaCallAdapterFactory.createWithScheduler(Schedulers.io());

        return new Retrofit.Builder()
                .baseUrl(Constants.BASE_URL)
                .client(httpClient.build())
                .addCallAdapterFactory(rxAdapter)
                .addConverterFactory(GsonConverterFactory.create())
                .build().create(RetrofitInterface.class);
    }

    public static RetrofitInterface getRetrofit(String token) {

        OkHttpClient.Builder httpClient = new OkHttpClient.Builder();

        httpClient.addInterceptor(chain -> {

            Request original = chain.request();
            Request.Builder builder = original.newBuilder()
                    .addHeader("x-access-token", token)
                    .method(original.method(),original.body());
            return  chain.proceed(builder.build());

        });

        RxJavaCallAdapterFactory rxAdapter = RxJavaCallAdapterFactory.createWithScheduler(Schedulers.io());

        return new Retrofit.Builder()
                .baseUrl(Constants.BASE_URL)
                .client(httpClient.build())
                .addCallAdapterFactory(rxAdapter)
                .addConverterFactory(GsonConverterFactory.create())
                .build().create(RetrofitInterface.class);
    }
}

The RegisterFragment handles register operation. Here we use Java 8 lambda function for OnClickListener instead of Anonymous function. The register() function check for validation and throws error. If there is no error registerProcess() function is called. We initialise a CompositeSubscription object and add all the RxJava subscriptions to it. During onDestroy() we unsubscribe the subscriptions. This prevents memory leak. The network operation is carried out by,

NetworkUtil.getRetrofit().register(user) .observeOn(AndroidSchedulers.mainThread()) .subscribeOn(Schedulers.io()) .subscribe(this::handleResponse,this::handleError)

The observeOn() and subscribeOn() defines, in which thread we need to handle the results and perform the network operation. Here we have defined the results should be delivered and handled in main thread and the network operation should be handled in IO thread. The handleResponse() and handleError methods are called for success and failure. We are using Java 8 Lambda shorthand functions for handleResponse and handleError methods. Else we need to write,

subscribe(response -> handleResponse(response), error -> handleError(error))

Instead of the above code we are simplifying using this operator,

subscribe(this::handleResponse,this::handleError)

We display the success and failure messages in the Snackbar.

package com.learn2crack.fragments;

import android.app.Fragment;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.design.widget.Snackbar;
import android.support.design.widget.TextInputLayout;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ProgressBar;
import android.widget.TextView;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.learn2crack.R;
import com.learn2crack.model.Response;
import com.learn2crack.model.User;
import com.learn2crack.network.NetworkUtil;

import java.io.IOException;

import retrofit2.adapter.rxjava.HttpException;
import rx.android.schedulers.AndroidSchedulers;
import rx.schedulers.Schedulers;
import rx.subscriptions.CompositeSubscription;

import static com.learn2crack.utils.Validation.validateEmail;
import static com.learn2crack.utils.Validation.validateFields;

public class RegisterFragment extends Fragment {

    public static final String TAG = RegisterFragment.class.getSimpleName();

    private EditText mEtName;
    private EditText mEtEmail;
    private EditText mEtPassword;
    private Button   mBtRegister;
    private TextView mTvLogin;
    private TextInputLayout mTiName;
    private TextInputLayout mTiEmail;
    private TextInputLayout mTiPassword;
    private ProgressBar mProgressbar;

    private CompositeSubscription mSubscriptions;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.fragment_register,container,false);
        mSubscriptions = new CompositeSubscription();
        initViews(view);
        return view;
    }

    private void initViews(View v) {

        mEtName = (EditText) v.findViewById(R.id.et_name);
        mEtEmail = (EditText) v.findViewById(R.id.et_email);
        mEtPassword = (EditText) v.findViewById(R.id.et_password);
        mBtRegister = (Button) v.findViewById(R.id.btn_register);
        mTvLogin = (TextView) v.findViewById(R.id.tv_login);
        mTiName = (TextInputLayout) v.findViewById(R.id.ti_name);
        mTiEmail = (TextInputLayout) v.findViewById(R.id.ti_email);
        mTiPassword = (TextInputLayout) v.findViewById(R.id.ti_password);
        mProgressbar = (ProgressBar) v.findViewById(R.id.progress);

        mBtRegister.setOnClickListener(view -> register());
        mTvLogin.setOnClickListener(view -> goToLogin());
    }

    private void register() {

        setError();

        String name = mEtName.getText().toString();
        String email = mEtEmail.getText().toString();
        String password = mEtPassword.getText().toString();

        int err = 0;

        if (!validateFields(name)) {

            err++;
            mTiName.setError("Name should not be empty !");
        }

        if (!validateEmail(email)) {

            err++;
            mTiEmail.setError("Email should be valid !");
        }

        if (!validateFields(password)) {

            err++;
            mTiPassword.setError("Password should not be empty !");
        }

        if (err == 0) {

            User user = new User();
            user.setName(name);
            user.setEmail(email);
            user.setPassword(password);

            mProgressbar.setVisibility(View.VISIBLE);
            registerProcess(user);

        } else {

            showSnackBarMessage("Enter Valid Details !");
        }
    }

    private void setError() {

        mTiName.setError(null);
        mTiEmail.setError(null);
        mTiPassword.setError(null);
    }

    private void registerProcess(User user) {

        mSubscriptions.add(NetworkUtil.getRetrofit().register(user)
                .observeOn(AndroidSchedulers.mainThread())
                .subscribeOn(Schedulers.io())
                .subscribe(this::handleResponse,this::handleError));
    }

    private void handleResponse(Response response) {

        mProgressbar.setVisibility(View.GONE);
        showSnackBarMessage(response.getMessage());
    }

    private void handleError(Throwable error) {

        mProgressbar.setVisibility(View.GONE);

        if (error instanceof HttpException) {

            Gson gson = new GsonBuilder().create();

            try {

                String errorBody = ((HttpException) error).response().errorBody().string();
                Response response = gson.fromJson(errorBody,Response.class);
                showSnackBarMessage(response.getMessage());

            } catch (IOException e) {
                e.printStackTrace();
            }
        } else {

            showSnackBarMessage("Network Error !");
        }
    }

    private void showSnackBarMessage(String message) {

        if (getView() != null) {

            Snackbar.make(getView(),message,Snackbar.LENGTH_SHORT).show();
        }
    }

    private void goToLogin(){

        FragmentTransaction ft = getFragmentManager().beginTransaction();
        LoginFragment fragment = new LoginFragment();
        ft.replace(R.id.fragmentFrame, fragment, LoginFragment.TAG);
        ft.commit();
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        mSubscriptions.unsubscribe();
    }
}

The LoginFragment is similar to the RegisterFragment. The server returns a token on successful authentication. We store the token in SharedPreferences. Then ProfileActivity is launched.

package com.learn2crack.fragments;

import android.app.Fragment;
import android.app.FragmentTransaction;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.support.annotation.Nullable;
import android.support.design.widget.Snackbar;
import android.support.design.widget.TextInputLayout;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ProgressBar;
import android.widget.TextView;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.learn2crack.ProfileActivity;
import com.learn2crack.R;
import com.learn2crack.model.Response;
import com.learn2crack.network.NetworkUtil;
import com.learn2crack.utils.Constants;

import java.io.IOException;

import retrofit2.adapter.rxjava.HttpException;
import rx.android.schedulers.AndroidSchedulers;
import rx.schedulers.Schedulers;
import rx.subscriptions.CompositeSubscription;

import static com.learn2crack.utils.Validation.validateEmail;
import static com.learn2crack.utils.Validation.validateFields;

public class LoginFragment extends Fragment {

    public static final String TAG = LoginFragment.class.getSimpleName();

    private EditText mEtEmail;
    private EditText mEtPassword;
    private Button mBtLogin;
    private TextView mTvRegister;
    private TextView mTvForgotPassword;
    private TextInputLayout mTiEmail;
    private TextInputLayout mTiPassword;
    private ProgressBar mProgressBar;

    private CompositeSubscription mSubscriptions;
    private SharedPreferences mSharedPreferences;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_login,container,false);
        mSubscriptions = new CompositeSubscription();
        initViews(view);
        initSharedPreferences();
        return view;
    }

    private void initViews(View v) {

        mEtEmail = (EditText) v.findViewById(R.id.et_email);
        mEtPassword = (EditText) v.findViewById(R.id.et_password);
        mBtLogin = (Button) v.findViewById(R.id.btn_login);
        mTiEmail = (TextInputLayout) v.findViewById(R.id.ti_email);
        mTiPassword = (TextInputLayout) v.findViewById(R.id.ti_password);
        mProgressBar = (ProgressBar) v.findViewById(R.id.progress);
        mTvRegister = (TextView) v.findViewById(R.id.tv_register);
        mTvForgotPassword = (TextView) v.findViewById(R.id.tv_forgot_password);

        mBtLogin.setOnClickListener(view -> login());
        mTvRegister.setOnClickListener(view -> goToRegister());
        mTvForgotPassword.setOnClickListener(view -> showDialog());
    }

    private void initSharedPreferences() {

        mSharedPreferences = PreferenceManager.getDefaultSharedPreferences(getActivity());
    }

    private void login() {

        setError();

        String email = mEtEmail.getText().toString();
        String password = mEtPassword.getText().toString();

        int err = 0;

        if (!validateEmail(email)) {

            err++;
            mTiEmail.setError("Email should be valid !");
        }

        if (!validateFields(password)) {

            err++;
            mTiPassword.setError("Password should not be empty !");
        }

        if (err == 0) {

            loginProcess(email,password);
            mProgressBar.setVisibility(View.VISIBLE);

        } else {

            showSnackBarMessage("Enter Valid Details !");
        }
    }

    private void setError() {

        mTiEmail.setError(null);
        mTiPassword.setError(null);
    }

    private void loginProcess(String email, String password) {

        mSubscriptions.add(NetworkUtil.getRetrofit(email, password).login()
                .observeOn(AndroidSchedulers.mainThread())
                .subscribeOn(Schedulers.io())
                .subscribe(this::handleResponse,this::handleError));
    }

    private void handleResponse(Response response) {

        mProgressBar.setVisibility(View.GONE);

        SharedPreferences.Editor editor = mSharedPreferences.edit();
        editor.putString(Constants.TOKEN,response.getToken());
        editor.putString(Constants.EMAIL,response.getMessage());
        editor.apply();

        mEtEmail.setText(null);
        mEtPassword.setText(null);

        Intent intent = new Intent(getActivity(), ProfileActivity.class);
        startActivity(intent);

    }

    private void handleError(Throwable error) {

        mProgressBar.setVisibility(View.GONE);

        if (error instanceof HttpException) {

            Gson gson = new GsonBuilder().create();

            try {

                String errorBody = ((HttpException) error).response().errorBody().string();
                Response response = gson.fromJson(errorBody,Response.class);
                showSnackBarMessage(response.getMessage());

            } catch (IOException e) {
                e.printStackTrace();
            }
        } else {

            showSnackBarMessage("Network Error !");
        }
    }

    private void showSnackBarMessage(String message) {

        if (getView() != null) {

            Snackbar.make(getView(),message,Snackbar.LENGTH_SHORT).show();
        }
    }

    private void goToRegister(){

        FragmentTransaction ft = getFragmentManager().beginTransaction();
        RegisterFragment fragment = new RegisterFragment();
        ft.replace(R.id.fragmentFrame,fragment,RegisterFragment.TAG);
        ft.commit();
    }

    private void showDialog(){

        ResetPasswordDialog fragment = new ResetPasswordDialog();

        fragment.show(getFragmentManager(), ResetPasswordDialog.TAG);
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        mSubscriptions.unsubscribe();
    }
}

The ChangePasswordDialog extends to DialogFragment. It has process similar to other Fragments. Also it has a callback interface which is used to notify the parent Activity when the process is successful.

The interface is defined as,

public interface Listener {
   void onPasswordChanged();
}

Our ProfileActivity implements this interface. It is initialised in onAttach() lifecycle method.

Listener mListener = (ProfileActivity)context;

package com.learn2crack.fragments;

import android.app.DialogFragment;
import android.content.Context;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.design.widget.TextInputLayout;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ProgressBar;
import android.widget.TextView;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.learn2crack.ProfileActivity;
import com.learn2crack.R;
import com.learn2crack.model.Response;
import com.learn2crack.model.User;
import com.learn2crack.network.NetworkUtil;
import com.learn2crack.utils.Constants;

import java.io.IOException;

import retrofit2.adapter.rxjava.HttpException;
import rx.android.schedulers.AndroidSchedulers;
import rx.schedulers.Schedulers;
import rx.subscriptions.CompositeSubscription;

import static com.learn2crack.utils.Validation.validateFields;

public class ChangePasswordDialog extends DialogFragment {

    public interface Listener {

        void onPasswordChanged();
    }

    public static final String TAG = ChangePasswordDialog.class.getSimpleName();

    private EditText mEtOldPassword;
    private EditText mEtNewPassword;
    private Button mBtChangePassword;
    private Button mBtCancel;
    private TextView mTvMessage;
    private TextInputLayout mTiOldPassword;
    private TextInputLayout mTiNewPassword;
    private ProgressBar mProgressBar;

    private CompositeSubscription mSubscriptions;

    private String mToken;
    private String mEmail;

    private Listener mListener;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.dialog_change_password,container,false);
        mSubscriptions = new CompositeSubscription();
        getData();
        initViews(view);
        return view;
    }

    private void getData() {

        Bundle bundle = getArguments();

        mToken = bundle.getString(Constants.TOKEN);
        mEmail = bundle.getString(Constants.EMAIL);
    }

    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        mListener = (ProfileActivity)context;
    }

    private void initViews(View v) {

        mEtOldPassword = (EditText) v.findViewById(R.id.et_old_password);
        mEtNewPassword = (EditText) v.findViewById(R.id.et_new_password);
        mTiOldPassword = (TextInputLayout) v.findViewById(R.id.ti_old_password);
        mTiNewPassword = (TextInputLayout) v.findViewById(R.id.ti_new_password);
        mTvMessage = (TextView) v.findViewById(R.id.tv_message);
        mBtChangePassword = (Button) v.findViewById(R.id.btn_change_password);
        mBtCancel = (Button) v.findViewById(R.id.btn_cancel);
        mProgressBar = (ProgressBar) v.findViewById(R.id.progress);

        mBtChangePassword.setOnClickListener(view -> changePassword());
        mBtCancel.setOnClickListener(view -> dismiss());
    }

    private void changePassword() {

        setError();

        String oldPassword = mEtOldPassword.getText().toString();
        String newPassword = mEtNewPassword.getText().toString();

        int err = 0;

        if (!validateFields(oldPassword)) {

            err++;
            mTiOldPassword.setError("Password should not be empty !");
        }

        if (!validateFields(newPassword)) {

            err++;
            mTiNewPassword.setError("Password should not be empty !");
        }

        if (err == 0) {

            User user = new User();
            user.setPassword(oldPassword);
            user.setNewPassword(newPassword);
            changePasswordProgress(user);
            mProgressBar.setVisibility(View.VISIBLE);

        }
    }

    private void setError() {

        mTiOldPassword.setError(null);
        mTiNewPassword.setError(null);
    }

    private void changePasswordProgress(User user) {

        mSubscriptions.add(NetworkUtil.getRetrofit(mToken).changePassword(mEmail,user)
                .observeOn(AndroidSchedulers.mainThread())
                .subscribeOn(Schedulers.io())
                .subscribe(this::handleResponse,this::handleError));
    }

    private void handleResponse(Response response) {

        mProgressBar.setVisibility(View.GONE);
        mListener.onPasswordChanged();
        dismiss();
    }

    private void handleError(Throwable error) {

        mProgressBar.setVisibility(View.GONE);

        if (error instanceof HttpException) {

            Gson gson = new GsonBuilder().create();

            try {

                String errorBody = ((HttpException) error).response().errorBody().string();
                Response response = gson.fromJson(errorBody,Response.class);
                showMessage(response.getMessage());

            } catch (IOException e) {
                e.printStackTrace();
            }
        } else {

            showMessage("Network Error !");
        }
    }

    private void showMessage(String message) {

        mTvMessage.setVisibility(View.VISIBLE);
        mTvMessage.setText(message);

    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        mSubscriptions.unsubscribe();
    }
}

The working ResetPasswordDialog is similar to ChangePasswordDialog with some small changes. It has two process. First is to initiate the Password reset process with email, second is to change the password using the temporary token obtained via email. Both process have same success and failure callback methods with a boolean isInit to check which process is executing.

Also we have a public setToken() method. This method will be called from our ProfileActivity. We sent a email with a URI to click. The URI will be similar to http://learn2crack/{token}. We set a Intent filter in our ProfileActivity to open our App when this link is opened. Token from this URI is extracted and passed to this setToken() method and set to EditText automatically.

This also has a similar callback which is implemented in MainActivity.

package com.learn2crack.fragments;

import android.app.DialogFragment;
import android.content.Context;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.design.widget.TextInputLayout;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ProgressBar;
import android.widget.TextView;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.learn2crack.MainActivity;
import com.learn2crack.R;
import com.learn2crack.model.Response;
import com.learn2crack.model.User;
import com.learn2crack.network.NetworkUtil;

import java.io.IOException;

import retrofit2.adapter.rxjava.HttpException;
import rx.android.schedulers.AndroidSchedulers;
import rx.schedulers.Schedulers;
import rx.subscriptions.CompositeSubscription;

import static com.learn2crack.utils.Validation.validateEmail;
import static com.learn2crack.utils.Validation.validateFields;

public class ResetPasswordDialog extends DialogFragment {

    public interface Listener {

        void onPasswordReset(String message);
    }

    public static final String TAG = ResetPasswordDialog.class.getSimpleName();

    private EditText mEtEmail;
    private EditText mEtToken;
    private EditText mEtPassword;
    private Button mBtResetPassword;
    private TextView mTvMessage;
    private TextInputLayout mTiEmail;
    private TextInputLayout mTiToken;
    private TextInputLayout mTiPassword;
    private ProgressBar mProgressBar;

    private CompositeSubscription mSubscriptions;

    private String mEmail;

    private boolean isInit = true;

    private Listener mListner;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.dialog_reset_password,container,false);
        mSubscriptions = new CompositeSubscription();
        initViews(view);
        return view;
    }

    private void initViews(View v) {

        mEtEmail = (EditText) v.findViewById(R.id.et_email);
        mEtToken = (EditText) v.findViewById(R.id.et_token);
        mEtPassword = (EditText) v.findViewById(R.id.et_password);
        mBtResetPassword = (Button) v.findViewById(R.id.btn_reset_password);
        mProgressBar = (ProgressBar) v.findViewById(R.id.progress);
        mTvMessage = (TextView) v.findViewById(R.id.tv_message);
        mTiEmail = (TextInputLayout) v.findViewById(R.id.ti_email);
        mTiToken = (TextInputLayout) v.findViewById(R.id.ti_token);
        mTiPassword = (TextInputLayout) v.findViewById(R.id.ti_password);

        mBtResetPassword.setOnClickListener(view -> {
            if (isInit) resetPasswordInit();
            else resetPasswordFinish();
        });
    }

    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        mListner = (MainActivity)context;
    }

    private void setEmptyFields() {

        mTiEmail.setError(null);
        mTiToken.setError(null);
        mTiPassword.setError(null);
        mTvMessage.setText(null);
    }

    public void setToken(String token) {

        mEtToken.setText(token);
    }

    private void resetPasswordInit() {

        setEmptyFields();

        mEmail = mEtEmail.getText().toString();

        int err = 0;

        if (!validateEmail(mEmail)) {

            err++;
            mTiEmail.setError("Email Should be Valid !");
        }

        if (err == 0) {

            mProgressBar.setVisibility(View.VISIBLE);
            resetPasswordInitProgress(mEmail);
        }
    }

    private void resetPasswordFinish() {

        setEmptyFields();

        String token = mEtToken.getText().toString();
        String password = mEtPassword.getText().toString();

        int err = 0;

        if (!validateFields(token)) {

            err++;
            mTiToken.setError("Token Should not be empty !");
        }

        if (!validateFields(password)) {

            err++;
            mTiEmail.setError("Password Should not be empty !");
        }

        if (err == 0) {

            mProgressBar.setVisibility(View.VISIBLE);

            User user = new User();
            user.setPassword(password);
            user.setToken(token);
            resetPasswordFinishProgress(user);
        }
    }

    private void resetPasswordInitProgress(String email) {

        mSubscriptions.add(NetworkUtil.getRetrofit().resetPasswordInit(email)
                .observeOn(AndroidSchedulers.mainThread())
                .subscribeOn(Schedulers.io())
                .subscribe(this::handleResponse,this::handleError));
    }

    private void resetPasswordFinishProgress(User user) {

        mSubscriptions.add(NetworkUtil.getRetrofit().resetPasswordFinish(mEmail,user)
                .observeOn(AndroidSchedulers.mainThread())
                .subscribeOn(Schedulers.io())
                .subscribe(this::handleResponse,this::handleError));
    }

    private void handleResponse(Response response) {

        mProgressBar.setVisibility(View.GONE);

        if (isInit) {

            isInit = false;
            showMessage(response.getMessage());
            mTiEmail.setVisibility(View.GONE);
            mTiToken.setVisibility(View.VISIBLE);
            mTiPassword.setVisibility(View.VISIBLE);

        } else {

            mListner.onPasswordReset(response.getMessage());
            dismiss();
        }
    }

    private void handleError(Throwable error) {

        mProgressBar.setVisibility(View.GONE);

        if (error instanceof HttpException) {

            Gson gson = new GsonBuilder().create();

            try {

                String errorBody = ((HttpException) error).response().errorBody().string();
                Response response = gson.fromJson(errorBody,Response.class);
                showMessage(response.getMessage());

            } catch (IOException e) {
                e.printStackTrace();
            }
        } else {

            showMessage("Network Error !");
        }
    }

    private void showMessage(String message) {

        mTvMessage.setVisibility(View.VISIBLE);
        mTvMessage.setText(message);

    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        mSubscriptions.unsubscribe();
    }
}

Our MainActivity acts as a controller for Fragments. This implements onNewIntent() method. This will be called when the URI is opened. We parse the URI and extract token info then pass to ResetPasswordDialog.

It also implements onPasswordReset() callback method from ResetPasswordDialog which is used to display a Snackbar message.

package com.learn2crack;

import android.content.Intent;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;

import com.learn2crack.fragments.LoginFragment;
import com.learn2crack.fragments.ResetPasswordDialog;

public class MainActivity extends AppCompatActivity implements ResetPasswordDialog.Listener {

    public static final String TAG = MainActivity.class.getSimpleName();

    private LoginFragment mLoginFragment;
    private ResetPasswordDialog mResetPasswordDialog;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        if (savedInstanceState == null) {

            loadFragment();
        }
    }

    private void loadFragment(){

        if (mLoginFragment == null) {

            mLoginFragment = new LoginFragment();
        }
        getFragmentManager().beginTransaction().replace(R.id.fragmentFrame,mLoginFragment,LoginFragment.TAG).commit();
    }

    @Override
    protected void onNewIntent(Intent intent) {
        super.onNewIntent(intent);

        String data = intent.getData().getLastPathSegment();
        Log.d(TAG, "onNewIntent: "+data);

        mResetPasswordDialog = (ResetPasswordDialog) getFragmentManager().findFragmentByTag(ResetPasswordDialog.TAG);

        if (mResetPasswordDialog != null)
            mResetPasswordDialog.setToken(data);
    }

    @Override
    public void onPasswordReset(String message) {

        showSnackBarMessage(message);
    }

    private void showSnackBarMessage(String message) {

        Snackbar.make(findViewById(R.id.activity_main),message,Snackbar.LENGTH_SHORT).show();

    }
}

The ProfileActivity implements Listener interface of ChangePasswordDialog. Profile Activity displays Name, Email and Password. It also has buttons for Change Password and Logout. When the Logout button is pressed the SharedPreferences data is removed and the Activity is destroyed.

package com.learn2crack;

import android.content.SharedPreferences;
import android.preference.PreferenceManager;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.TextView;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.learn2crack.fragments.ChangePasswordDialog;
import com.learn2crack.model.Response;
import com.learn2crack.model.User;
import com.learn2crack.network.NetworkUtil;
import com.learn2crack.utils.Constants;

import java.io.IOException;

import retrofit2.adapter.rxjava.HttpException;
import rx.android.schedulers.AndroidSchedulers;
import rx.schedulers.Schedulers;
import rx.subscriptions.CompositeSubscription;

public class ProfileActivity extends AppCompatActivity implements ChangePasswordDialog.Listener {

    public static final String TAG = ProfileActivity.class.getSimpleName();

    private TextView mTvName;
    private TextView mTvEmail;
    private TextView mTvDate;
    private Button mBtChangePassword;
    private Button mBtLogout;

    private ProgressBar mProgressbar;

    private SharedPreferences mSharedPreferences;
    private String mToken;
    private String mEmail;

    private CompositeSubscription mSubscriptions;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_profile);
        mSubscriptions = new CompositeSubscription();
        initViews();
        initSharedPreferences();
        loadProfile();
    }

    private void initViews() {

        mTvName = (TextView) findViewById(R.id.tv_name);
        mTvEmail = (TextView) findViewById(R.id.tv_email);
        mTvDate = (TextView) findViewById(R.id.tv_date);
        mBtChangePassword = (Button) findViewById(R.id.btn_change_password);
        mBtLogout = (Button) findViewById(R.id.btn_logout);
        mProgressbar = (ProgressBar) findViewById(R.id.progress);

        mBtChangePassword.setOnClickListener(view -> showDialog());
        mBtLogout.setOnClickListener(view -> logout());
    }

    private void initSharedPreferences() {

        mSharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
        mToken = mSharedPreferences.getString(Constants.TOKEN,"");
        mEmail = mSharedPreferences.getString(Constants.EMAIL,"");
    }

    private void logout() {

        SharedPreferences.Editor editor = mSharedPreferences.edit();
        editor.putString(Constants.EMAIL,"");
        editor.putString(Constants.TOKEN,"");
        editor.apply();
        finish();
    }

    private void showDialog(){

        ChangePasswordDialog fragment = new ChangePasswordDialog();

        Bundle bundle = new Bundle();
        bundle.putString(Constants.EMAIL, mEmail);
        bundle.putString(Constants.TOKEN,mToken);
        fragment.setArguments(bundle);

        fragment.show(getFragmentManager(), ChangePasswordDialog.TAG);
    }

    private void loadProfile() {

        mSubscriptions.add(NetworkUtil.getRetrofit(mToken).getProfile(mEmail)
                .observeOn(AndroidSchedulers.mainThread())
                .subscribeOn(Schedulers.io())
                .subscribe(this::handleResponse,this::handleError));
    }

    private void handleResponse(User user) {

        mProgressbar.setVisibility(View.GONE);
        mTvName.setText(user.getName());
        mTvEmail.setText(user.getEmail());
        mTvDate.setText(user.getCreated_at());
    }

    private void handleError(Throwable error) {

        mProgressbar.setVisibility(View.GONE);

        if (error instanceof HttpException) {

            Gson gson = new GsonBuilder().create();

            try {

                String errorBody = ((HttpException) error).response().errorBody().string();
                Response response = gson.fromJson(errorBody,Response.class);
                showSnackBarMessage(response.getMessage());

            } catch (IOException e) {
                e.printStackTrace();
            }
        } else {

            showSnackBarMessage("Network Error !");
        }
    }

    private void showSnackBarMessage(String message) {

        Snackbar.make(findViewById(R.id.activity_profile),message,Snackbar.LENGTH_SHORT).show();

    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        mSubscriptions.unsubscribe();
    }

    @Override
    public void onPasswordChanged() {

        showSnackBarMessage("Password Changed Successfully !");
    }
}

We need to define Intent filter for MainActivity so that when the URI http://learn2crack/{token} is opened, it will launch our MainActivity. Also we have set the launch mode as singleTask so that new Activity is not created and the data is passed to existing Activity and onNewIntent() method is called.

<activity
    android:name=".MainActivity"
    android:theme="@style/AppTheme.LoginRegister"
    android:launchMode="singleTask">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
            <action android:name="android.intent.action.VIEW" />
            <category android:name="android.intent.category.DEFAULT" />
            <category android:name="android.intent.category.BROWSABLE" />
            <data android:scheme="http"
                  android:host="learn2crack" />
        </intent-filter>
</activity>

Finally run the project.

Enjoy Coding 😃