PROGRAM 13:
XML CODE:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:app="http://schemas.android.com/apk/res-auto"
 xmlns:tools="http://schemas.android.com/tools"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:orientation="vertical"
 android:gravity="center"
 android:padding="24dp"
 tools:context=".MainActivity">
 <TextView
 android:id="@+id/modetext"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:text="Current mode:"
 android:textSize="18sp"
 android:layout_marginBottom="24dp"/>
 <Button
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:id="@+id/normalbtn"
 android:text="Normal Mode"/>
 <Button
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:id="@+id/silentbtn"
 android:text="Silent Mode"
 android:layout_marginTop="16dp"/>
 <Button
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:id="@+id/vibratebtn"
 android:text="Vibrate Mode"
 android:layout_marginTop="16dp"/>
</LinearLayout>
JAVA CODE:
package com.example.prgm13;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.media.AudioManager;
import android.widget.Button;
import android.widget.Switch;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
 AudioManager audioManager;
 TextView modeText;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 audioManager = (AudioManager) getSystemService(AUDIO_SERVICE);
 modeText = findViewById(R.id.modetext);
 Button nbtn = findViewById(R.id.normalbtn);
 Button sbtn = findViewById(R.id.silentbtn);
 Button vbtn = findViewById(R.id.vibratebtn);
 updateModeText();
 nbtn.setOnClickListener(v->{
 audioManager.setRingerMode(AudioManager.RINGER_MODE_NORMAL);
 updateModeText();
 });
 sbtn.setOnClickListener(v->{
 audioManager.setRingerMode(AudioManager.RINGER_MODE_SILENT);
 updateModeText();
 });
 vbtn.setOnClickListener(v->{
 audioManager.setRingerMode(AudioManager.RINGER_MODE_VIBRATE);
 updateModeText();
 });
 }
 private void updateModeText() {
 int mode = audioManager.getRingerMode();
 String modestr;
 switch (mode) {
 case AudioManager.RINGER_MODE_NORMAL:
 modestr = "NORMAL";
 break;
 case AudioManager.RINGER_MODE_SILENT:
 modestr = "SILENT";
 break;
 case AudioManager.RINGER_MODE_VIBRATE:
 modestr = "VIBRATE";
 break;
 default:
 modestr = "UNKNOWN";
 break;
 }
 modeText.setText("Current mode: " + modestr);
 }
}
MANIFEST.XML CODE:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:tools="http://schemas.android.com/tools"
 package="com.example.prgm13">
 <uses-permission
android:name="android.permission.MODIFY_AUDIO_SETTINGS"/>
 <application
 android:allowBackup="true"
 android:dataExtractionRules="@xml/data_extraction_rules"
 android:fullBackupContent="@xml/backup_rules"
 android:icon="@mipmap/ic_launcher"
 android:label="@string/app_name"
 android:roundIcon="@mipmap/ic_launcher_round"
 android:supportsRtl="true"
 android:theme="@style/Theme.Prgm13"
 tools:targetApi="31">
 <activity
 android:name=".MainActivity"
 android:exported="true">
 <intent-filter>
 <action android:name="android.intent.action.MAIN" />
 <category android:name="android.intent.category.LAUNCHER" />
 </intent-filter>
 </activity>
 </application>
</manifest>