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首先要明白需要的情景，然后对三种方式进行选择：

（一）可以接收Service的信息(获取Service中的方法)，但不可以给Service发送信息

package com.example.boundservice;

import java.util.Random;

import android.R.integer;
import android.app.Service;
import android.content.Intent;
import android.os.Binder;
import android.os.IBinder;

public class LocalService extends Service {
	
	private IBinder myBinder = new MyBinder();

	@Override
	public IBinder onBind(Intent arg0) {
		// TODO Auto-generated method stub
		return myBinder;
	}
	public class MyBinder extends Binder {
		 LocalService getService() {
	            return LocalService.this;
	        }
	}
	public int getRandomNumber() {
		return new Random().nextInt(100);
	}

}

package com.example.boundservice;

import com.example.boundservice.LocalService.MyBinder;

import android.app.Activity;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.IBinder;
import android.view.View;
import android.widget.TextView;

public class BindingActivity extends Activity implements ServiceConnection{
	private LocalService localService;
	private MyBinder myBinder;
	boolean mBound = false;
	
	@Override
	protected void onStart() {
		// TODO Auto-generated method stub
		super.onStart();
		Intent intent = new Intent(this,LocalService.class);
		bindService(intent, this, Context.BIND_AUTO_CREATE);
	}
	
	@Override
	protected void onStop() {
        super.onStop(); 
        // Unbind from the service
	    if (mBound) {
	    	unbindService(this);
	        mBound = false;
	    }
    }
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_binding_activity);
		findViewById(R.id.button_show_binding_text).setOnClickListener(new View.OnClickListener() {
			@Override
			public void onClick(View arg0) {
				((TextView)findViewById(R.id.textview)).setText(+localService.getRandomNumber());
			}
		});
	}
	
	@Override
	public void onServiceConnected(ComponentName arg0, IBinder arg1) {
		myBinder = (MyBinder)arg1;
		localService = myBinder.getService();
		mBound = true;
	}
	
	@Override
	public void onServiceDisconnected(ComponentName arg0) {
		 mBound = false;
	}
}

(二) 使用Messenger既可以接受Service消息，也可以发送Service消息。但是无法调用Service中的方法。因为利用Message,所以不用担心并发

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