MySmsApp/app/src/main/java/com/example/mysmsapp/MainActivity.java

package com.example.mysmsapp;

import android.app.role.RoleManager;
import android.content.Intent;
import android.os.Build;
import android.os.Bundle;
import android.provider.Settings;
import android.util.Log;
import android.widget.Toast;

import androidx.activity.EdgeToEdge;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.graphics.Insets;
import androidx.core.view.ViewCompat;
import androidx.core.view.WindowInsetsCompat;

public class MainActivity extends AppCompatActivity {
    private static final String TAG = "MainActivity";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        EdgeToEdge.enable(this);
        setContentView(R.layout.activity_main);
        ViewCompat.setOnApplyWindowInsetsListener(findViewById(R.id.main), (v, insets) -> {
            Insets systemBars = insets.getInsets(WindowInsetsCompat.Type.systemBars());
            v.setPadding(systemBars.left, systemBars.top, systemBars.right, systemBars.bottom);
            return insets;
        });

        findViewById(R.id.btn_set_default).setOnClickListener(e -> {
            RoleManager roleManager;
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
                roleManager = getApplicationContext().getSystemService(RoleManager.class);
                if (roleManager.isRoleAvailable(RoleManager.ROLE_SMS)) {
                    if (roleManager.isRoleHeld(RoleManager.ROLE_SMS)) {
                        Toast.makeText(getApplicationContext(), "PrismApp set as default.", Toast.LENGTH_SHORT).show();
                        Intent i = new Intent(Settings.ACTION_MANAGE_DEFAULT_APPS_SETTINGS);
                        startActivity(i);
                    } else {
                        Intent roleRequestIntent = roleManager.createRequestRoleIntent(RoleManager.ROLE_SMS);
                        startActivityForResult(roleRequestIntent, 1);
                    }
                }
            }
        });

        findViewById(R.id.btn_send_sms).setOnClickListener(e -> {
            Intent intent = SmsUtils.getSmsIntent("10086", "Hello, world!");
            sendBroadcast(intent);
        });

        findViewById(R.id.btn_pdu).setOnClickListener(e -> {
            byte[] res = SmsUtils.createFakeSms("15077886171", "test");
            printPdu(res);
        });
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        Log.d(TAG, "onActivityResult: ");
    }

    public static void printPdu(byte[] bytes) {
        String s = "";
        for (byte b : bytes) {
            s += b + ", ";
        }
        Log.d("PDU", s);
    }
}