receive boot completed listener - android receiver example (mobile phone reload event handler)

different files

MainActivity.java:

package com.alex.receivers;

import android.Manifest;
import android.content.IntentFilter;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.widget.Toast;

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

public class MainActivity extends AppCompatActivity {

    private static final int PERMISSION_REQUEST_CODE = 100;
    MyReceiver r = new MyReceiver();

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

        if (checkPermission()) {
            onPermissionGranted();
        } else {
            requestPermission();
        }
    }

    private boolean checkPermission() {
        return ContextCompat.checkSelfPermission(this, Manifest.permission.RECEIVE_BOOT_COMPLETED)
                == PackageManager.PERMISSION_GRANTED;
    }

    private void requestPermission() {
        ActivityCompat.requestPermissions(this,
                new String[]{Manifest.permission.RECEIVE_BOOT_COMPLETED},
                PERMISSION_REQUEST_CODE);
    }

    private void onPermissionGranted() {
        Toast.makeText(this, "Permissions Granted!", Toast.LENGTH_SHORT).show();
        var i = new IntentFilter("android.intent.action.BOOT_COMPLETED");
        registerReceiver(r, i);
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if (requestCode == PERMISSION_REQUEST_CODE) {
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                onPermissionGranted();
            } else {
                Toast.makeText(this, "Permission Denied", Toast.LENGTH_SHORT).show();
            }
        }
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        unregisterReceiver(r);
    }
}

====================================================================================================================================

MyReceiver.java:

package com.alex.receivers;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;

public class MyReceiver extends BroadcastReceiver {

    public void onReceive(Context context, Intent intent) {
        if (intent != null && "android.permission.RECEIVE_BOOT_COMPLETED".equals(intent.getAction())) {
            var i = new Intent(context, MainActivity.class);
            i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            context.startActivity(i);
        }
    }
}

====================================================================================================================================

AndroidManifest.xml:

...

    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />

    ...

        <receiver
            android:name=".MyReceiver"
            android:enabled="true"
            android:permission="android.permission.RECEIVE_BOOT_COMPLETED"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.BOOT_COMPLETED" />
            </intent-filter>

        </receiver>
    </application>

</manifest>