How do I programmatically “restart” an Android app?

There are some situations, we need to restart whole application programmatically. This example demonstrates how do I programmatically “restart” an Android app.
Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.
Step 2 − Add the following code to res/layout/activity_main.xml.
<?xml version = "1.0" encoding = "utf-8"?>
<LinearLayout xmlns:android = "http://schemas.android.com/apk/res/android"
   android:id = "@+id/parent"
   xmlns:tools = "http://schemas.android.com/tools"
   android:layout_width = "match_parent"
   android:layout_height = "match_parent"
   tools:context = ".MainActivity"
   android:gravity = "center"
   android:orientation = "vertical">
   <TextView
      android:id = "@+id/text"
      android:textSize = "28sp"
      android:textAlignment = "center"
      android:layout_width = "match_parent"
      android:layout_height = "wrap_content" />
</LinearLayout>
In the above code, we have taken a text view. When the user clicks on text view, it will restart the whole application.
package com.example.andy.myapplication;
import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.os.Build;
import android.os.Bundle;
import android.support.annotation.RequiresApi;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
   int view = R.layout.activity_main;
   TextView textview;
   @RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN)
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(view);
      textview = findViewById(R.id.text);
      textview.setText("Click here to restart activity");
      textview.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
            Intent mStartActivity = new Intent(MainActivity.this, MainActivity.class);
            int mPendingIntentId = 123456;
            PendingIntent mPendingIntent = PendingIntent.getActivity(MainActivity.this, mPendingIntentId, mStartActivity, PendingIntent.FLAG_CANCEL_CURRENT);
            AlarmManager mgr = (AlarmManager)MainActivity.this.getSystemService(Context.ALARM_SERVICE);
            mgr.set(AlarmManager.RTC, System.currentTimeMillis() + 100, mPendingIntent);
System.exit(0);
         }
      });
   }
}
In the above code, we have taken text view, when a user clicks on text view, it will restart the whole application as shown below -
Intent mStartActivity = new Intent(MainActivity.this, MainActivity.class);
int mPendingIntentId = 123456;
PendingIntent mPendingIntent = PendingIntent.getActivity(MainActivity.this, mPendingIntentId, mStartActivity, PendingIntent.FLAG_CANCEL_CURRENT);
AlarmManager mgr = (AlarmManager)MainActivity.this.getSystemService(Context.ALARM_SERVICE);
mgr.set(AlarmManager.RTC, System.currentTimeMillis() + 100, mPendingIntent);
System.exit(0);
Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from android studio, open one of your project's activity files and click Run  icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen −
When you click on text view, it will restart application again after some time.
Click here to download the project code