Android 基础之接口回调

概述

接口回调其本质与上转型是一样的，不同的是：接口回调是用接口句柄来得到并调用实现这个接口的子类的引用；而上转型则是用父类句柄来得到并调用继承此父类的子类的引用。

实例

1. 创建一个接口：

public interface MyBroadcastListener{

     void doSomething(String value);

}

2. 在您的 BroadcastReceiver 中初始化监听器

public class MyReceiver extends BroadcastReceiver {

    private MyBroadcastListener listener;

    public MyReceiver(MyBroadcastListener listener){
        this.listener = listener;
    }

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

        listener.doSomething("Some Result");

    }
}

3. 在您的 Activity 中实现接口并重写方法

 public MainActivity extends AppCompatActivity implements MyBroadcastListener{

      private BroadcastReceiver receiver;

      @Override
      public void onCreate(Bundle sis){

           // Related code 

           receiver = new MyReceiver(this);   // This is how you initialise receiver

          // 注册广播
          ...
      }


      public void updateUI(String msg) {
           TextView textView = (TextView) findViewById(R.id.textView);
           textView .setText(msg);
      }

      @Override
      public void doSomething(String result){
           updateUI(result);        // Calling method from Interface
      }

 }