Introdução ao Android Studio e às notificações por push

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="MY_PACKAGE_IDENTIFIER">
    <uses-permission android:name="android.permission.INTERNET" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <!-- The following block enables our custom Firebase Instance ID Service-->
        <service android:name=".FooAppFirebaseInstanceIdService" android:exported="true">
            <intent-filter>
                <action android:name="com.google.firebase.INSTANCE_ID_EVENT"/>
            </intent-filter>
        </service>

        <service
            android:name=".FooAppFirebaseMessagingService" android:exported="true">
            <intent-filter>
                <action android:name="com.google.firebase.MESSAGING_EVENT"/>
            </intent-filter>
        </service>

    </application>

</manifest>

package PACKAGE_IDENTIFIER;

import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import com.playfab.PlayFabClientAPI;
import com.playfab.PlayFabClientModels.*;
import com.playfab.PlayFabErrors;
import com.playfab.PlayFabSettings;
import java.util.List;
import java.util.Map;

public class MainActivity extends AppCompatActivity {

    // Invoked when activity is started
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Set PlayFab title
        PlayFabSettings.TitleId = "PLAYFAB_TITLE_ID";

        // Start login operation
        AsyncTask.execute(new Runnable() {
            @Override
            public void run() {
                if(login()) FooAppFirebaseInstanceIdService.setAllowRegisterForPush(true); // Ready to register for push notifications
            }
        });
    }

    public boolean login(){
        LoginWithAndroidDeviceIDRequest request = new LoginWithAndroidDeviceIDRequest();
        request.CreateAccount = true;

        // There are several approaches on getting unique android device id.
        // https://stackoverflow.com/questions/2785485/is-there-a-unique-android-device-id
        request.AndroidDeviceId = "qwerty";

        PlayFabErrors.PlayFabResult<LoginResult> response = PlayFabClientAPI.LoginWithAndroidDeviceID(request);
        if(response.Error != null){
            Log.d("Foo PlayFab App",CompileErrorsFromResult(response.Error));
            return false;
        }
        return true;
    }

    // Utility method to compose an error message out of PlayFab result.
    private static String CompileErrorsFromResult(PlayFabErrors.PlayFabError error) {
        if (error == null)
            return null;

        String errorMessage = "";
        if (error.errorMessage != null)
            errorMessage += error.errorMessage;
        if (error.errorDetails != null)
            for (Map.Entry<String, List<String>> pair : error.errorDetails.entrySet())
                for (String msg : pair.getValue())
                    errorMessage += "\n" + pair.getKey() + ": " + msg;
        return errorMessage;
    }
}

package PACKAGE_IDENTIFIER;

import android.text.TextUtils;
import android.util.Log;
import com.google.firebase.iid.FirebaseInstanceId;
import com.google.firebase.iid.FirebaseInstanceIdService;
import com.playfab.PlayFabClientAPI;
import com.playfab.PlayFabClientModels;
import com.playfab.PlayFabErrors;
import java.util.List;
import java.util.Map;

public class FooAppFirebaseInstanceIdService extends FirebaseInstanceIdService {

    private static String _token;

    private static boolean _allowRegistration;

    // This is invoked from activity that performs authentication.
    // Once login is complete this method is invoked.
    // If we have a pending token, we use it to register for push notifications
    public static void setAllowRegisterForPush(boolean isAllowed) {
        _allowRegistration = isAllowed;
        if (_allowRegistration && !TextUtils.isEmpty(_token)) {
            registerForPush(_token);
        }
    }

    // Invoked when firebase has fetched a token
    // If we already have logged in, we use new token to register for push
    @Override
    public void onTokenRefresh() {
        _token = FirebaseInstanceId.getInstance().getToken();
        if (_allowRegistration && !TextUtils.isEmpty(_token)) {
            registerForPush(_token);
        }
    }

    private static void registerForPush(String token) {
        PlayFabClientModels.AndroidDevicePushNotificationRegistrationRequest request = new PlayFabClientModels.AndroidDevicePushNotificationRegistrationRequest();
        request.DeviceToken = token;

        PlayFabErrors.PlayFabResult<PlayFabClientModels.AndroidDevicePushNotificationRegistrationResult> response = PlayFabClientAPI.AndroidDevicePushNotificationRegistration(request);

        if (response.Error != null) {
            Log.d("Foo PlayFab App", CompileErrorsFromResult(response.Error));
        }
    }

    // Utility method to compose an error message out of PlayFab result.
    private static String CompileErrorsFromResult(PlayFabErrors.PlayFabError error) {
        if (error == null)
            return null;

        String errorMessage = "";
        if (error.errorMessage != null)
            errorMessage += error.errorMessage;
        if (error.errorDetails != null)
            for (Map.Entry<String, List<String>> pair : error.errorDetails.entrySet())
                for (String msg : pair.getValue())
                    errorMessage += "\n" + pair.getKey() + ": " + msg;
        return errorMessage;
    }

}

package com.foo.playfab.app;

import android.util.Log;
import com.google.firebase.messaging.FirebaseMessagingService;
import com.google.firebase.messaging.RemoteMessage;

public class FooAppFirebaseMessagingService extends FirebaseMessagingService {

    @Override
    public void onMessageReceived(RemoteMessage message) {
        // Intercept the message here
        Log.d("Foo PlayFab App","Message received: "+message.getNotification().getBody());
    }
}