This example demonstrates how do I show a dialog to confirm that the user wishes to exit an Android Activity.
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"?> <RelativeLayout xmlns:android="https://schemas.android.com/apk/res/android" xmlns:tools="https://schemas.android.com/tools" android:id="@+id/relativeLayout" android:layout_width="match_parent" android:layout_height="match_parent" android:padding="16dp" tools:context=".MainActivity"> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerInParent="true" android:text="Dialog to confirm that the user wishes to exit an Android Activity" android:textAlignment="center" android:textSize="24sp" android:textStyle="bold" /> </RelativeLayout>
Step 3 − Add the following code to src/MainActivity.java
import androidx.appcompat.app.AlertDialog; import androidx.appcompat.app.AppCompatActivity; import android.content.DialogInterface; import android.os.Bundle; import android.widget.Toast; public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } @Override public void onBackPressed() { newAlertDialog.Builder(this).setIcon(android.R.drawable.ic_dialog_alert) .setTitle("Closing Activity").setMessage("Are you sure you want to closethis activity?") .setPositiveButton("Yes", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { finish(); Toast.makeText(MainActivity.this, "Activity closed",Toast.LENGTH_SHORT).show(); } }).setNegativeButton("No", null).show(); } }
Step 4 − Add the following code to androidManifest.xml
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="https://schemas.android.com/apk/res/android" package="app.com.sample"> <application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:roundIcon="@mipmap/ic_launcher_round" 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> </application> </manifest>
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 the 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 −