android展示手机电量

package com.basillee.asus.demo;import android.app.Notification;import android.content.BroadcastReceiver;import android.content.Context;import android.content.Intent;import android.content.IntentFilter;import android.os.BatteryManager;import android.support.v7.app.ActionBarActivity;import android.os.Bundle;import android.view.Menu;import android.view.MenuItem;import android.view.View;import android.widget.Button;import android.widget.TextView;public class MainActivity11 extends ActionBarActivity {    private TextView textViewLevel=null;    private int batteryLevel;    private int batteryScale;    private Button buttonBatteryShow;    private BroadcastReceiver broadcastReceiver=new BroadcastReceiver() {        @Override        public void onReceive(Context context, Intent intent) {            //获取当前电量，如未获取具体数值，则默认为0            batteryLevel=intent.getIntExtra(BatteryManager.EXTRA_LEVEL,0);            //获取最大电量，如未获取到具体数值，则默认为100            batteryScale=intent.getIntExtra(BatteryManager.EXTRA_SCALE,100);            //显示电量            textViewLevel.setText("电量"+(batteryLevel*100/batteryScale)+"%");        }    };    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main_activity11);        textViewLevel= (TextView) findViewById(R.id.textViewBattery);        buttonBatteryShow= (Button) findViewById(R.id.button_show_battery);        buttonBatteryShow.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                IntentFilter intentFilter=new IntentFilter(Intent.ACTION_BATTERY_CHANGED);                //注册接收器以获取电量信息                registerReceiver(broadcastReceiver, intentFilter);            }        });    }}