Android中回调接口的使用

MainActivity如下:

package cn.testcallback;
import android.os.Bundle;
import android.app.Activity;
/**
 * Demo描述:
 * Android中回调接口的使用
 */
public class MainActivity extends Activity {
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		testCallBack();
	}
	private void testCallBack(){
		AskQuestion askQuestion=new AskQuestion();
		String questionString="Do you love me ?";
		System.out.println("The question is : "+questionString);	
		askQuestion.askQuestion(questionString);
	}

}

CallBackInterface如下:

package cn.testcallback;
/**
 * 定义一个接口
 * 接口中有一方法
 */
public interface CallBackInterface {
	public void answerQuestion(String result);
}

AskQuestion如下:

package cn.testcallback;

public class AskQuestion implements CallBackInterface{
    public void askQuestion(final String questionString){
    	new Thread(){
    		public void run() {
    			AnswerQuestion answerQuestion=new AnswerQuestion();
    			answerQuestion.receiveQuestion(AskQuestion.this, questionString);
    		};
    	}.start();
    }
	@Override
	public void answerQuestion(String result) {
        System.out.println("The answter is : "+result);		
	}

}

AnswerQuestion如下:

package cn.testcallback;

public class AnswerQuestion {
   public void receiveQuestion(CallBackInterface callBackInterface,String questionString){
		try {
            Thread.sleep(3000);
		} catch (Exception e) {
		}
		String result="YES!!!";
		callBackInterface.answerQuestion(result);
   }
}

main.xml如下:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
   >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="回调的使用" 
        android:layout_centerInParent="true"
    />

</RelativeLayout>