Secure your android java codes from decompile or reverse engineering

One Idea, If you implement JAVA 8 library with your android projects, then it is impossible to decompile by any tools available. I will show you how you implement that.

There is 2 types of gradle files:
1. Project's gradle.build and
2. App's gradle.build

For point. 1 you make changes like:

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:2.2.3'

        // ADD THIS
        classpath 'me.tatarka:gradle-retrolambda:3.2.5'        

}

Then For point 2, there are some additions are required like:

apply plugin: 'com.android.application'
// ADD THIS
apply plugin: 'me.tatarka.retrolambda'

android {
// ADD THIS
compileOptions {
targetCompatibility 1.8
sourceCompatibility 1.8    }
}

Yupp, thats all. My friend. Your codes are secured from any type of reverse engineering.

Note: Plus point is you can use LAMBDA with your logic now. And addition with
compile 'com.annimon:stream:1.0.9'
You can use JAVA STREAM as well.. ;)

Set timer with interval at starting on boot, Show notification on proper event/condition

First of all, we create Class that starts at Boot

public class OnBootReceiver extends BroadcastReceiver {

 @Override public void onReceive(Context context, Intent intent) {

  AlarmManager alarmMgr = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
  Intent intent = new Intent(context, OnBootCalling.class);
  PendingIntent alarmIntent = PendingIntent.getBroadcast(context, 0, intent, 0);
  Calendar calendar = Calendar.getInstance();
  calendar.set(Calendar.HOUR_OF_DAY, Constant.alarmHour);
  calendar.set(Calendar.MINUTE, Constant.alarmMinute);

  alarmMgr.setRepeating(AlarmManager.RTC, calendar.getTimeInMillis(),
   Constant.alarmInterval, alarmIntent);

 }

and add this to your androidManifest.xml

<receiver    android:name=".OnBootReceiver"    android:enabled="true">
    <intent-filter>
        <category android:name="android.intent.category.DEFAULT" />

        <action android:name="android.intent.action.BOOT_COMPLETED" />
        <action android:name="android.intent.action.QUICKBOOT_POWERON" />
        <action android:name="android.intent.action.REBOOT" />
    </intent-filter>
</receiver>

So, everytime, On specific time, as set in Alarm, will call OnBootCalling.class

public class OnBootCalling extends WakefulBroadcastReceiver {
 @Override
 public void onReceive(Context context, Intent intent) {

  if (conditionIsSatisfied)
   ComponentName comp = new ComponentName(context.getPackageName(),
    AlarmService.class.getName());
  startWakefulService(context, (intent.setComponent(comp)));
  setResultCode(Activity.RESULT_OK);
  break;
 }
}
}
}
}

which will call AlarmService.class, which will call notification

public class AlarmService extends IntentService {

 public AlarmService() {
  super("AlarmService");
 }

 @Override
 public void onHandleIntent(Intent intent) {

  //If you want to play default sound with notification 
  Uri alarmUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
  Ringtone ringtone = RingtoneManager.getRingtone(PlayerApp.getContext(), alarmUri);
  ringtone.play();

  Intent intent = new Intent(PlayerApp.getContext(), MainActivity.class);
  intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
  PendingIntent pendingIntent = PendingIntent.getActivity(getContext(), 0, intent, 0);

  Uri defaultSoundUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
  NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(PlayerApp.getContext())
   .setSmallIcon(R.drawable.ic_music)
   .setLargeIcon(BitmapFactory.decodeResource(getContext().getResources(), R.drawable.ic_music))
   .setContentTitle("Alert")
   .setTicker("Ticking Alert")
   .setStyle(new NotificationCompat.BigTextStyle().bigText("For BigView, Your Message comes here"))
   .setContentText("Your Message comes here")
   .setAutoCancel(true)
   .setSound(defaultSoundUri)
   .setContentIntent(pendingIntent);
  //                .addAction (R.drawable.ic_menu_manage,
  //                        getString(R.string.anyaction), pendingIntent);

  NotificationManager notificationManager =
   (NotificationManager) getContext().getSystemService(Context.NOTIFICATION_SERVICE);

  notificationManager.notify(401, notificationBuilder.build());
 }
}

Note: Make sure you get proper context

Do not forget to add these lines to your Manifest

<receiver android:name=".OnBootCalling" />

<service android:name=".AlarmService" android:enabled="true" />

Also add these permissions

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

Hope, this helps you somewhere.

default clock packages including Marshmallow to open Alarm in android

String clockImpls[][] = {
        {"Sony Ericsson Xperia Z", "com.sonyericsson.organizer", "com.sonyericsson.organizer.Organizer_WorldClock"},
        {"ASUS Alarm Clock", "com.asus.alarmclock", "com.asus.alarmclock.AlarmClock"},
        {"ASUS Desk Clock", "com.asus.deskclock", "com.asus.deskclock.DeskClock"},
        {"Sony Alarm", "com.sonyericsson.alarm", "com.sonyericsson.alarm.Alarm"},
        {"Standard Alarm", "com.android.alarmclock", "com.android.alarmclock.AlarmClock"},
        {"Marshmallow Alarm", "com.android.deskclock", "com.android.deskclock.DeskClock"},
        {"HTC Alarm ClockDT", "com.htc.android.worldclock", "com.htc.android.worldclock.WorldClockTabControl"},
        {"Standard Alarm ClockDT", "com.android.deskclock", "com.android.deskclock.AlarmClock"},
        {"Froyo Nexus Alarm ClockDT", "com.google.android.deskclock", "com.android.deskclock.DeskClock"},
        {"Moto Blur Alarm ClockDT", "com.motorola.blur.alarmclock", "com.motorola.blur.alarmclock.AlarmClock"},
        {"Samsung Galaxy S", "com.sec.android.app.clockpackage", "com.sec.android.app.clockpackage.ClockPackage"}};

Full Code for clock widget


import android.app.PendingIntent;
import android.appwidget.AppWidgetManager;
import android.appwidget.AppWidgetProvider;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.content.pm.PackageManager.NameNotFoundException;
import android.util.Log;
import android.widget.RemoteViews;

public class ClockWidget extends AppWidgetProvider {

    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        PendingIntent pendingIntent;
        if (AppWidgetManager.ACTION_APPWIDGET_UPDATE.equals(action)) {

            RemoteViews views = new RemoteViews(context.getPackageName(),
                    R.layout.clock_widget);

            try {
                pendingIntent = PendingIntent.getActivity(context, 0, getAlarmPackage(context), 0);
                views.setOnClickPendingIntent(R.id.clock, pendingIntent);
            } catch (Exception e) {
                Log.e("pendingExceptions", e.getMessage() + " " + getAlarmPackage(context));
            }

            AppWidgetManager
                    .getInstance(context)
                    .updateAppWidget(
                            intent.getIntArrayExtra(AppWidgetManager.EXTRA_APPWIDGET_IDS),
                            views);
        }
    }

    public Intent getAlarmPackage(Context context) {
        PackageManager packageManager = context.getPackageManager();
        Intent AlarmClockIntent = new Intent(Intent.ACTION_MAIN).addCategory(Intent.CATEGORY_LAUNCHER);

        String clockImpls[][] = {
                {"Sony Ericsson Xperia Z", "com.sonyericsson.organizer", "com.sonyericsson.organizer.Organizer_WorldClock"},
                {"ASUS Alarm Clock", "com.asus.alarmclock", "com.asus.alarmclock.AlarmClock"},
                {"ASUS Desk Clock", "com.asus.deskclock", "com.asus.deskclock.DeskClock"},
                {"Sony Alarm", "com.sonyericsson.alarm", "com.sonyericsson.alarm.Alarm"},
                {"Standard Alarm", "com.android.alarmclock", "com.android.alarmclock.AlarmClock"},
                {"Marshmallow Alarm", "com.android.deskclock", "com.android.deskclock.DeskClock"},
                {"HTC Alarm ClockDT", "com.htc.android.worldclock", "com.htc.android.worldclock.WorldClockTabControl"},
                {"Standard Alarm ClockDT", "com.android.deskclock", "com.android.deskclock.AlarmClock"},
                {"Froyo Nexus Alarm ClockDT", "com.google.android.deskclock", "com.android.deskclock.DeskClock"},
                {"Moto Blur Alarm ClockDT", "com.motorola.blur.alarmclock", "com.motorola.blur.alarmclock.AlarmClock"},
                {"Samsung Galaxy S", "com.sec.android.app.clockpackage", "com.sec.android.app.clockpackage.ClockPackage"}};

        boolean foundClockImpl = false;

        for (String[] clockImpl : clockImpls) {
            String packageName = clockImpl[1];
            String className = clockImpl[2];
            try {
                ComponentName cn = new ComponentName(packageName, className);
                packageManager.getActivityInfo(cn, PackageManager.GET_META_DATA);
                AlarmClockIntent.setComponent(cn);
                foundClockImpl = true;
            } catch (NameNotFoundException ignored) {
            }
        }
        if (foundClockImpl) {
            return AlarmClockIntent;
        } else {
            return null;
        }
    }
}

Confirm Exit OnBackpressed click back twice.

@Overridepublic void onBackPressed() {
    confirmExit(MainActivity.this);
}

import android.support.v4.app.ActivityCompat;

public static boolean doubleBackToExitPressedOnce = false;

@TargetApi(Build.VERSION_CODES.JELLY_BEAN)
public static void confirmExit(AppCompatActivity context) {
    if (doubleBackToExitPressedOnce) {
        ActivityCompat.finishAffinity(context);
    }

    doubleBackToExitPressedOnce = true;
    Toast.makeText(context, "Please click BACK again to exit", Toast.LENGTH_SHORT).show();

    new Handler().postDelayed(new Runnable() {

        @Override        public void run() {
            doubleBackToExitPressedOnce = false;
        }
    }, 2000);
}

Having gradle build issue with unknown reason?

Go to terminal
Type

gradlew build

and Enter.. Wait.. it will work..

Firebase Messaging Service Example Android

Add gradle dependency,

dependencies {
    compile 'com.google.firebase:firebase-messaging:9.0.0'}

Create MyFirebaseInstanceIDService.java and MyFirebaseMessagingService.java



import android.util.Log;

import com.google.firebase.iid.FirebaseInstanceId;
import com.google.firebase.iid.FirebaseInstanceIdService;


public class MyFirebaseInstanceIDService extends FirebaseInstanceIdService {

    private static final String TAG = "MyFirebaseIIDService";

    @Override
    public void onTokenRefresh() {
        // Get updated InstanceID token.        String refreshedToken = FirebaseInstanceId.getInstance().getToken();
        Log.d(TAG, "Refreshed token: " + refreshedToken);

        sendRegistrationToServer(refreshedToken);
    }
  
    private void sendRegistrationToServer(String token) {
        // here implement method that sends token to store somewhere to reuse.    }
}

and

import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.media.RingtoneManager;
import android.net.Uri;
import android.support.v4.app.NotificationCompat;
import android.util.Log;

import com.google.firebase.messaging.FirebaseMessagingService;
import com.google.firebase.messaging.RemoteMessage;

public class MyFirebaseMessagingService extends FirebaseMessagingService {

    private static final String TAG = "MyFirebaseMsgService";

    /**     * Called when message is received.     *     * @param remoteMessage Object representing the message received from Firebase Cloud Messaging.     */
    @Override
    public void onMessageReceived(RemoteMessage remoteMessage) {
        // TODO(developer): Handle FCM messages here.        // If the application is in the foreground handle both data and notification messages here.        // Also if you intend on generating your own notifications as a result of a received FCM        // message, here is where that should be initiated. See sendNotification method below.        Log.d(TAG, "From: " + remoteMessage.getFrom());
        Log.d(TAG, "Notification Message Body: " + remoteMessage.getNotification().getBody());
        sendNotification(remoteMessage.getNotification().getBody());
    }

    private void sendNotification(String messageBody) {
        Intent intent = new Intent(this, MainActivity.class);
        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        PendingIntent pendingIntent = PendingIntent.getActivity(this, 0 /* Request code */, intent,
                PendingIntent.FLAG_ONE_SHOT);

        Uri defaultSoundUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
        NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this)
                .setSmallIcon(R.drawable.ic_stat_ic_notification)
                .setContentTitle("FCM Message")
                .setContentText(messageBody)
                .setAutoCancel(true)
                .setSound(defaultSoundUri)
                .setContentIntent(pendingIntent);

        NotificationManager notificationManager =
                (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);

        notificationManager.notify(0 /* ID of notification */, notificationBuilder.build());
    }
}

Add these to AndroidManifest.xml, 

<service    android:name=".MyFirebaseMessagingService">
    <intent-filter>
        <action android:name="com.google.firebase.MESSAGING_EVENT"/>
    </intent-filter>
</service>
<service    android:name=".MyFirebaseInstanceIDService">
    <intent-filter>
        <action android:name="com.google.firebase.INSTANCE_ID_EVENT"/>
    </intent-filter>
</service>

That's it. Very Simple. Here is sample that is getting through RemoteMessage.


Log.d(TAG, "remoteMessage" + remoteMessage.getData());
Log.d(TAG, "APS: " + remoteMessage.getData().get("aps"));

private String id, title, msg, type, image, sound;
try {
    if (remoteMessage.getData() != null) {
        id = remoteMessage.getData().get("id");
        title = remoteMessage.getData().get("title");
        msg = remoteMessage.getData().get("msg");
        type = remoteMessage.getData().get("type");
        image = remoteMessage.getData().get("image");
        sound = remoteMessage.getData().get("sound");

        sendNotification();
        }
    }
} catch (Exception e) {
    e.printStackTrace();
}

Retrofit 2 demo example

First of all, add gradle dependency

dependencies {

compile 'com.squareup.retrofit2:retrofit:2.1.0'    

compile 'com.squareup.retrofit2:converter-gson:2.0.0'    

compile 'com.squareup.okhttp3:logging-interceptor:3.2.0'}

Check for updated version.

Make one class that handle retrofit stuff

NetCall.java

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonObject;

import okhttp3.OkHttpClient;
import okhttp3.ResponseBody;
import okhttp3.logging.HttpLoggingInterceptor;
import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;
import retrofit2.Retrofit;
import retrofit2.converter.gson.GsonConverterFactory;
import retrofit2.http.Body;
import retrofit2.http.POST;

/** * Created by axay on 09-05-2016. */

public class NetCall {
    String baseUrl = "http://example.com/service/";
    public Request request;

    public Call<JsonObject> featuredPlaylist(JsonObject jsonObject) {
        return request.featuredPlaylist(jsonObject);
    }

    public Call<JsonObject> allUserPlaylist(JsonObject jsonObject) {
        return request.allUserPlaylist(jsonObject);
    }

    public interface Request{
        @POST("library/featuredplaylist.php")
        Call<JsonObject> featuredPlaylist(@Body JsonObject jsonObject);

        @POST("library/alluserplaylist.php")
        Call<JsonObject> allUserPlaylist(@Body JsonObject jsonObject);

    }


    public NetCall(){
        Gson gson = new GsonBuilder().disableHtmlEscaping().create();

        HttpLoggingInterceptor interceptor = new HttpLoggingInterceptor();
        interceptor.setLevel(HttpLoggingInterceptor.Level.BODY);
        OkHttpClient client = new OkHttpClient.Builder().addInterceptor(interceptor).build();

        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl(baseUrl)
                .client(client)
                .addConverterFactory(GsonConverterFactory.create(gson))
                .build();

        request = retrofit.create(Request.class);
    }
}

Now call this wherever you want.

Suppose In MainActivity.java


import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;

import com.google.gson.JsonObject;

import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;

public class MainActivity extends AppCompatActivity {

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

        JsonObject jsonObject = new JsonObject();

        new NetCall().featuredPlaylist(jsonObject).enqueue(new Callback<JsonObject>() {
            @Override
            public void onResponse(Call<JsonObject> call, Response<JsonObject> response) {
                JsonObject jsonObject1 = response.body();
            }

            @Override
            public void onFailure(Call<JsonObject> call, Throwable t) {

            }
        });

        new NetCall().allUserPlaylist(jsonObject).enqueue(new Callback<JsonObject>() {
            @Override
            public void onResponse(Call<JsonObject> call, Response<JsonObject> response) {
                JsonObject jsonObject1 = response.body();
            }

            @Override
            public void onFailure(Call<JsonObject> call, Throwable t) {

            }
        });
    }
}

Now Parse JsonObject as per your requirements got in onResponse(...).