This example demonstrates how to create a simple Broadcast Receiver. It does not require any Android Manifest changes for permissions since the battery does not require it.

-----------------------------------------
1. Add a class called BatteryChecker.java
-----------------------------------------

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

public class BatteryChecker extends BroadcastReceiver {
    public void onReceive(Context context, Intent intent) {

            String action = intent.getAction();

            if(action.equals(Intent.ACTION_POWER_CONNECTED)) {
                // Do something when power connected
                Toast.makeText(context,"Power Connected",Toast.LENGTH_SHORT).show();
            }
            else if(action.equals(Intent.ACTION_POWER_DISCONNECTED)) {
                Toast.makeText(context,"Power Disconnected",Toast.LENGTH_SHORT).show();
            }
        }

    }


---------------------------
2. Update MainActivity.java
---------------------------

import androidx.appcompat.app.AppCompatActivity;                                   
import android.content.BroadcastReceiver;                                          
import android.content.IntentFilter;                                               
import android.os.Bundle;                                                          
                                                                                   
public class MainActivity extends AppCompatActivity {                              
                                                                                   
        BroadcastReceiver receiver;                                                
                                                                                   
        protected void onCreate(Bundle savedInstanceState) {                       
            super.onCreate(savedInstanceState);                                    
            setContentView(R.layout.activity_main);                                
                                                                                   
            configureReceiver();                                                   
        }                                                                          
                                                                                   
        private void configureReceiver() {                                         
            IntentFilter filter = new IntentFilter();                              
            filter.addAction("com.example.myapplication.BatteryChecker");           
            filter.addAction("android.intent.action.ACTION_POWER_DISCONNECTED");   
            filter.addAction("android.intent.action.ACTION_POWER_CONNECTED");      
            receiver = new BatteryChecker();                                       
            registerReceiver(receiver, filter);                                    
        }                                                                          
                                                                                   
    }                                                                              
                                                                                   
------------------------------------------------------
3. Compile and Run - No changes to Manifest are needed
------------------------------------------------------