Android 中，Broadcast是一种在应用程序之间进行传输信息的机制。BroadcastReceiver对发送过来的Broadcast进行过滤和响应。根据这种机制，我们可以获取电池现有电量等信息。
1、实例化BroadcastReceiver
在接受信息的时候，可以通过intent.getAction().equals(Intent.ACTION_BATTERY_CHANGED)来判断接收的信息是否为电池电量变化信息。如果是，就获取此信息的详细情况。
1 private BroadcastReceiver batteryInfoReceiver =
new BroadcastReceiver() {
2 @Override
3 public void onReceive(Context context, Intent intent) {
4 if(intent.getAction().equals(Intent.ACTION_BATTERY_CHANGED)){
5 int level = intent.getIntExtra("level", 0
);
6 int scale = intent.getIntExtra("scale", 100
);
7 batteryView.setText("BatteryLevel " + String.valueOf(level*100/scale)+"%"
);
8 }
9 }
10 };
2、注册消息接收器
在onResume方法内注册消息接收器用来接收消息
registerReceiver(batteryInfoReceiver, new IntentFilter(Intent.ACTION_BATTERY_CHANGED));
3、注销消息接收器
在onPause方法内注销消息接收器
unregisterReceiver(batteryInfoReceiver);
4、完整代码
1 public class MainActivity
extends AppCompatActivity {
2
3 private TextView batteryView;
4 private BroadcastReceiver batteryInfoReceiver =
new BroadcastReceiver() {
5 @Override
6 public void onReceive(Context context, Intent intent) {
7 if(intent.getAction().equals(Intent.ACTION_BATTERY_CHANGED)){
8 int level = intent.getIntExtra("level", 0
);
9 int scale = intent.getIntExtra("scale", 100
);
10 batteryView.setText("BatteryLevel " + String.valueOf(level*100/scale)+"%"
);
11 }
12 }
13 };
14
15 @Override
16 protected void onCreate(Bundle savedInstanceState) {
17 super.onCreate(savedInstanceState);
18 setContentView(R.layout.activity_main);
19
20 batteryView = (TextView)
this.findViewById(R.id.batteryView);
21 }
22
23 @Override
24 protected void onResume(){
25 super.onResume();
26 registerReceiver(batteryInfoReceiver,
new IntentFilter(Intent.ACTION_BATTERY_CHANGED));
27 }
28
29 @Override
30 protected void onPause(){
31 super.onPause();
32 unregisterReceiver(batteryInfoReceiver);
33 }
34 }
版权声明：本文为博主原创文章，未经博主允许不得转载。
转载于:https://www.cnblogs.com/doodle777/p/Android_BroadcastReceiver.html
