在Android開發過程中，Android API 已經有了startService方式，為什麼還需要bindService呢？

答：是因為bindService可以實現Activity-->Service裡面的方法並返回資料給Activity，可以理解 在自身APP過程中Service與Activity進行通訊(本地服務)

　　bindService還可以實現另外強大的功能，需要結合AIDL，實現跨程序Service與Activity進行通訊(遠端服務)

定義介面來增強服務返回到Binder：

package liudeli.service1.service.inter;

 
import liudeli.service1.service.domain.Person;

public interface IPerson {

    /**
     * 通過ID查詢Person物件
     * @param id
     */
    public Person queryPersonByID(int id);

}

服務處理onBind方法：

package liudeli.service1.service;

import android.app.Service;

import android.content.Intent;
import
 
 android.os.Binder;
import android.os.IBinder;

import liudeli.service1.service.domain.Person;
import liudeli.service1.service.inter.IPerson;

public class MyService3 extends Service {

    @Override
    public IBinder onBind(Intent intent) {
        return new MyBinder();
    }

    class MyBinder extends
 
 Binder implements IPerson {

        /**
         * 通過ID查詢Person物件
         *
         * @param id
         */
        @Override
        public Person queryPersonByID(int id) {
            Person person = null;
            switch (id) {
                case 1:
                    person = new Person(1, "張三", 30);
                    break;
                case 2:
                    person = new Person(2, "李四", 20);
                    break;
                case 3:
                    person = new Person(3, "趙六", 26);
                    break;
                default:
                    person = new Person(9,"王五", 40);
                    break;
            }
            return person;
        }
    }
}

MainActivity3呼叫服務到方法：

package liudeli.service1;

import android.app.Activity;

import android.content.ComponentName;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.IBinder;
import android.util.Log;
import android.view.View;

import liudeli.service1.service.MyService3;
import liudeli.service1.service.inter.IPerson;

public class MainActivity3 extends Activity {

    private final static String TAG = MainActivity3.class.getSimpleName();

    private MyServiceConnection connection = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main3);

        connection = new MyServiceConnection();
    }

    public void bindService(View view) {
        bindService(new Intent(this, MyService3.class), connection, BIND_AUTO_CREATE);
    }

    public void unBindService(View view) {
        unbindService(connection);
    }

    private IPerson person = null;

    /**
     * 服務連線介面具體實現物件
     */
    class MyServiceConnection implements ServiceConnection {

        /**
         * 與服務進行連線
         * @param name
         * @param service
         */
        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            Log.d("MyService3", "與服務進行連線 name:" + name);

            person = (IPerson) service;
        }

        /**
         * 與服務斷開連線
         * @param name
         */
        @Override
        public void onServiceDisconnected(ComponentName name) {
            person = null;
            System.gc();
        }
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        if (null != connection) {
            unbindService(connection);
        }
    }

    public void testMothod(View view) {
        if (null != person) {
            liudeli.service1.service.domain.Person p = person.queryPersonByID(1);
            Log.d("MyService3", "p.toString" + p.toString());
        }
    }
}