Android 使用服务注册广播接收者

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //开启服务
        Intent intent = new Intent(this, ScreenService.class);
        startService(intent);
    }
}

public class ScreenService extends Service {

    private ScreenReceiver receiver;

    public ScreenService() {
    }

    @Override
    public IBinder onBind(Intent intent) {
        // TODO: Return the communication channel to the service.
//        throw new UnsupportedOperationException("Not yet implemented");
        return null;
    }

    @Override
    public void onCreate() {
        //1 创建ScreenReceiver实例
        receiver = new ScreenReceiver();
        //2 获取IntentFilter实例 目的是添加action
        IntentFilter filter = new IntentFilter();
        //3 添加action
        filter.addAction("android.intent.action.SCREEN_OFF");
        filter.addAction("android.intent.action.SCREEN_ON");
        //4 动态注册广播接收者
        registerReceiver(receiver, filter);
        super.onCreate();
    }

    @Override
    public void onDestroy() {
        //当服务销毁的时候 取消注册广播接收者
        unregisterReceiver(receiver);
        super.onDestroy();
    }
}

public class ScreenReceiver extends BroadcastReceiver {
    private static final String TAG = "jojo";
    @Override
    public void onReceive(Context context, Intent intent) {
        // TODO: This method is called when the BroadcastReceiver is receiving
        // an Intent broadcast.
//        throw new UnsupportedOperationException("Not yet implemented");
        //获取当前事件类型
        String action = intent.getAction();
        if ("android.intent.action.SCREEN_OFF".equals(action)) {
            Log.d(TAG, "onReceive: 屏幕锁屏了");
        } else if ("android.intent.action.SCREEN_ON".equals(action)) {
            Log.d(TAG, "onReceive: 屏幕解锁了");
        }
    }
}