Implementing a push notification service to your android application is a good idea to increase user engagement and thus better app ranking in playstore.

There are a many push notification services available for android.

• Firebase  –  SERVICE BY GOOGLE
• Urbanship
• PushWoosh
• Pushbots
• Onesignal

etc……..

I had experience with pushbots and  onesignal push notification

Onesignal push notification service is completely free and pushbots has limited free service.It will ask you to move to paid plans once you reached 10000 api requests.

I’m going to recommend onesignal and firebase . And in this article we concentrate on onesignal push notification service, as i said earlier its a free service.

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Main feature of onesignal push notification service are

 

dependencies {
    compile 'com.onesignal:OneSignal:3.+@aar'
    
    // Required for OneSignal, even if you have added FCM.
    compile 'com.google.android.gms:play-services-gcm:+'
    
    // Required for geotagging
    compile "com.google.android.gms:play-services-location:+"
    
    // play-services-analytics is only needed when using 8.1.0 or older. 
    // compile 'com.google.android.gms:play-services-analytics:+'
}

 

This is what instructed by onesignal  but i personally ignore this line

// Required for geotagging
    compile "com.google.android.gms:play-services-location:+"

when my apps not requires location services

Again in your build.gradle (Module: app) add these codes

android {
   defaultConfig {
      manifestPlaceholders = [onesignal_app_id: "PUT YOUR ONESIGNAL APP ID HERE",
                              // Project number pulled from dashboard, local value is ignored.
                              onesignal_google_project_number: "REMOTE"]
    }
 }

Replace “PUT YOUR ONESIGNAL APP ID HERE” line with  the App id generated by   Onesignal    (Looks like this — 8f8a37ad-cde9-4e00-95d1-2b1a7b97f891)

And

"REMOTE" with your google project number (Sender ID) you generated in Google developer console (Looks like this - 821236548745) 

Step 3

Add the following code to the onCreate method in your Applications “Main activity”.

import com.onesignal.OneSignal;

public class YourAppClass extends Application {
   @Override
   public void onCreate() {
      super.onCreate();
      OneSignal.startInit(this).init();
     
      // Sync hashed email if you have a login system or collect it.
      //   Will be used to reach the user at the most optimal time of day.
      // OneSignal.syncHashedEmail(userEmail);
   }
}

Step 4

Now build and run your application (Make sure it is connected to internet)

Now click “Check subscribed users”. if it shows your device, Then you are good to go.

Click  Done.

My recommendations 

From Android Lollipop 5.0 onwards  android only support small white icons for push notification. If you want to use icon with color then change applications  Targeted SDK to pre lollipop that is <21

targetSdkVersion 20

it is only recommended if you don't use lollipop specific features
And don't forget to add a small icon with name "ic_stat_onesignal_default"

to these folders ( i usually add a (72×72)  icon to res/drawable-mdpi/ folder and skip others. )

res/drawable-mdpi/   -  (24×24)    resolution

res/drawable-hdpi/   - (36×36)     resolution

res/drawable-xhdpi/  - (48×48)     resolution

res/drawable-xxhdpi/ - (72×72)      resolution

res/drawable-xxxhdpi/- (256×256) (Large Icon)  resolution