android - 我可以使用 BroadcastReceiver 的回调方法吗？

Question

学习使用 Android 中的 BroadcastReceiver 类，我编写了一个小程序来接收电池充电状态并将其写入 Activity 中的三个 TextView 字段。

但是，我将 BroadcastReceiver 作为一个单独的类，以使其更简单并与 Activity 分开。因此，我必须找到一种方法来告诉我的 Activity 类电池数据已更新，或者，这是我的解决方案，将对 TextView 字段的引用从 Activity 传递到 BroadcastReceiver 类。

有谁知道是否可以从 BroadcastReceiver 中创建一个回调方法来启动一个函数，f.ex。更新 TextView ()；在 Activity 中？

这是源代码——注意有两个 java 文件: http://pastebin.com/qjCTsSuH

问候，尼尔斯。

Answer 1

对我来说很有魅力的是将接口(interface)对象简单地声明为静态的。请记住，静态会导致与它们解决的问题一样多的问题，因为静态会在实例中保留它们的值。

public class MainActivity extends AppCompatActivity implements SocketMessageReceiver.ISocketMessageReceiver {

    //Declare the cb interface static in your activity
    private static SocketMessageReceiver.ISocketMessageReceiver iSocketMessageReceiver;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main_activity);

        //Assign this
        iSocketMessageReceiver = this;
        socketMessageReceiver.registerCallback(iSocketMessageReceiver);
    }

    @Override
    public void sendSocketMessage(String socketMessage) {
        lblEchoMessage.setText(socketMessage);
    }

}

在你的接收器中......

public class SocketMessageReceiver extends BroadcastReceiver {

    interface ISocketMessageReceiver {
        void sendSocketMessage(String socketMessage);
    }

    //Also declare the interface in your BroadcastReceiver as static
    private static ISocketMessageReceiver iSocketMessageReceiver;

    @Override
    public void onReceive(Context context, Intent intent) {

        if(intent.getAction().equals("com.WarwickWestonWright.SocketExample.RECEIVE")) {
            iSocketMessageReceiver.sendSocketMessage(intent.getBundleExtra("DATA").getString("DATA"));
        }

    }

    public void registerCallback(ISocketMessageReceiver iSocketMessageReceiver) {
        this.iSocketMessageReceiver = iSocketMessageReceiver;
    }

}