Battery Usage

package com.example.batteryusage;

import android.os.BatteryManager;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;

import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.widget.TextView;

/**
 * Used for finding the battery level of an Android-based phone.
 *
 *
 *
 */
public class BatteryLevelActivity extends Activity {
    /** Called when the activity is first created. */
    private TextView batterLevel;

    @Override
    /**
     * Called when the current activity is first created.
     */
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        setContentView(R.layout.activity_main);
        batterLevel = (TextView) this.findViewById(R.id.batteryLevel);
        batteryLevel();
    }

    /**
     * Android 2.0 or higher
     * Computes the battery level by registering a receiver to the intent triggered
     * by a battery status/level change.
     *
     * BatteryManager.Extra_Scale
        Integer containing the maximum battery level.
        BatteryManager.Extra_Level
        Integer field containing the current battery level, from 0 to EXTRA_SCALE.
     */
    private void batteryLevel() {
        BroadcastReceiver batteryLevelReceiver = new BroadcastReceiver() {
            public void onReceive(Context context, Intent intent) {
                context.unregisterReceiver(this);
                int rawlevel = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, -1);
                int scale = intent.getIntExtra(BatteryManager.EXTRA_SCALE, -1);
                int level = -1;
                if (rawlevel >= 0 && scale > 0) {
                    level = (rawlevel * 100) / scale;
                }
                batterLevel.setText("Battery Level Remaining: " + level + "%");
            }
        };
        IntentFilter batteryLevelFilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
        registerReceiver(batteryLevelReceiver, batteryLevelFilter);
    }
   
}