sms

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools">

    <!-- Permissions should be declared directly under the <manifest> element -->
    <uses-permission android:name="android.permission.SEND_SMS"/>
    <uses-permission android:name="android.permission.RECEIVE_SMS"/>

    <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.MyApplication"
        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>

mainactivity

package com.example.myapplication;

import android.Manifest;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.os.Handler;
import android.os.Looper;
import android.telephony.SmsManager;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class MainActivity extends AppCompatActivity {

    private ExecutorService executorService;
    private Handler mainHandler;

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

        executorService = Executors.newSingleThreadExecutor();
        mainHandler = new Handler(Looper.getMainLooper());

        // Request SMS permission at runtime
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.SEND_SMS)
                != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this,
                    new String[]{Manifest.permission.SEND_SMS}, 1);
        }

        findViewById(R.id.buttonSendSMS).setOnClickListener(v -> {
            String phoneNumber = "+91 7019384576"; // Replace with actual phone number
            String message = "Hello from my app!";
            sendSMSAsync(phoneNumber, message);
        });
    }

    private void sendSMSAsync(String phoneNumber, String message) {
        executorService.execute(() -> {
            try {
                SmsManager smsManager = SmsManager.getDefault();
                smsManager.sendTextMessage(phoneNumber, null, message, null, null);

                mainHandler.post(() ->
                        Toast.makeText(MainActivity.this, "SMS Sent Successfully!", Toast.LENGTH_SHORT).show()
                );
            } catch (Exception e) {
                e.printStackTrace();
                mainHandler.post(() ->
                        Toast.makeText(MainActivity.this, "SMS Failed: " + e.getMessage(), Toast.LENGTH_LONG).show()
                );
            }
        });
    }
}
activity xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:gravity="center"
    android:padding="16dp">

    <Button
        android:id="@+id/buttonSendSMS"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Send SMS"
        android:layout_gravity="center"
        android:layout_marginTop="100dp"/>
</LinearLayout>