package com.example.ubuntu.myinterface;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;

public class MainActivity extends AppCompatActivity implements Message.MessageChagneCallBackListening {

    private  String TAG = "MainActivity: ";
    private Message message;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        message = new Message();  //实例化 message 对象
        message.setOnMessageChangeListening(this); //传递监听示例对象，结果回调到这个类里面的方法

        Log.i(TAG,"传递原始数据");
        message.changeMesaage("Hello word"); //传递 数据处理
    }

    @Override
    public void sendMessage(String msg) {
        Log.i(TAG , "接口回调返回结果：　" + msg);
    }
}

package com.example.ubuntu.myinterface;

import android.content.Context;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;

public class Message {

    private String TAG = "Message: ";

    private MessageChagneCallBackListening messageChagneCallBackListening;

    public Message(){

    }

//主要就是 这一点 将实例化的 对象，传递进来
    public void setOnMessageChangeListening (MessageChagneCallBackListening messageChangeListening ){
        this.messageChagneCallBackListening = messageChangeListening;
        Log.i(TAG,"传递监听的实例化对象：　" + messageChangeListening);
    }


    public void changeMesaage(String msg){
        Log.i(TAG,"传进来的　ｍｓｇ : " + msg);

        String msgResult = "数据处理：`````" + msg;

        Log.i(TAG,"返回的处理结果：" + msgResult);
        messageChagneCallBackListening.sendMessage(msgResult);
    }

    //定义及一个接口用来传递数据   接口可以单独写在一个文件里
    interface MessageChagneCallBackListening{
        void sendMessage(String msg);
    }


}