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activity_main.xml中

<?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/register_btn"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="StartListenerBattery"/>
    <TextView
        android:id="@+id/battery_value"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="20sp"
        android:textColor="#FF0000"
        android:gravity="center"/>
</LinearLayout>

MainActivity中

public class MainActivity extends Activity {

    private BatteryChangedReceiver batteryChangedReceiver;
    private IntentFilter intentFilter1;
    private Button registerBtn;
    private TextView batteryValue;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        batteryValue = (TextView) findViewById(R.id.battery_value);
        registerBtn = (Button) findViewById(R.id.register_btn);

        //电量变化的action拦截
        batteryChangedReceiver = new BatteryChangedReceiver();
        intentFilter1 = new IntentFilter();
        intentFilter1.addAction(Intent.ACTION_BATTERY_CHANGED);

        //绑定点击事件：实现点击后 在TextView上显示电量信息，
        // 因为是点击后显示，所以要在onClick()中注册BroadCastReceiver
        registerBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                registerReceiver(batteryChangedReceiver,intentFilter1);//注册
            }
        });
    }

//  接收电量的BroadCastReceiver
    class BatteryChangedReceiver extends BroadcastReceiver{

        @Override
        public void onReceive(Context context, Intent intent) {
            //获取当前电量
            int level = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, 0);
            //获取最大电量
            int scale = intent.getIntExtra(BatteryManager.EXTRA_SCALE, 0);
            //计算电量百分比并写到TextView中
            batteryValue.setText("当前电量："+level*100/scale+"%");
        }
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        //取消注册
        unregisterReceiver(batteryChangedReceiver);
    }
}

结果（debug里）