通过一下代码方式就能时时的获取电量的变化信息，也可以通过BatteryManager对象里面的其他String 来获取其他信息，比如EXTRA_PLUGGED，这个是返回当前是用usb，交流电，无线电的方式等， 这里是比较简单的几行代码通过广播监听设备变化：
public class BatteryActivity extends Activity implements OnClickListener {
private Button startBtn, stopBtn;
private TextView batteryValue;
private BroadcastReceiver mReceiver;
private IntentFilter mFilter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.battery_layout);
startBtn = (Button) findViewById(R.id.start_btn);
stopBtn = (Button) findViewById(R.id.stop_btn);
batteryValue = (TextView) findViewById(R.id.battery_vaule);
batteryValue.setTextColor(Color.RED);
startBtn.setOnClickListener(this);
stopBtn.setOnClickListener(this);
mFilter = new IntentFilter();
// 监听电量变化，只能采用动态注册方式，不能在AndroidManifest.xml中用静态注册广播接受者
mFilter.addAction(Intent.ACTION_BATTERY_CHANGED);
mReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
// TODO Auto-generated method stub<br data-
// BatteryManager 包含了Intent.ACTION_BATTERY_CHANGED所需的String和常量值<br data-filtered="filtered">
// 当前电量
int level =intent.getIntExtra(BatteryManager.EXTRA_LEVEL, 0);
// 最大电量
int scale = intent.getIntExtra(BatteryManager.EXTRA_SCALE, 0);
batteryValue.setText("当前电量为:" + (level * 100) / scale + "%");
}
};
}
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
int id = v.getId();
switch (id) {
case R.id.start_btn:
registerReceiver(mReceiver, mFilter);
break;
case R.id.stop_btn:<
unregisterReceiver(mReceiver);
break;
default:
break;
}
}
@Override
protected void onDestroy() {
// TODO Auto-generated method stub<
super.onDestroy();
unregisterReceiver(mReceiver);
}
}
布局文件：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<Button
android:id="@+id/start_btn"
android:layout_width="100dp"
android:layout_height="50dp"
android:text="start" />
<Button
android:id="@+id/stop_btn"
android:layout_width="100dp"
android:layout_height="50dp"
android:text="stop" />
<TextView
android:id="@+id/battery_vaule"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="20sp" />
</LinearLayout>
