Android之Service学习篇二：Service启动方式之boundService

转于：

http://blog.csdn.net/wulianghuan/article/details/8600361

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上一篇中介绍了Service的第一种方式，startService，这一篇来讲解一下另一张方式 bindService。

当创建一个能提供绑定功能的服务时，我们必须提供一个IBinder对象，客户端能使用这个对象与服务进行交换。在Android中有三种定义方式：

1、扩展Binder类 (条件：服务和应用在同一个进程当中，是最常见的情况)

2、使用Messager

3、使用AIDL (Android Interface Defination Language)

 

 

Bound Services

 

A bound service is the server in a client-server interface. A bound service allows components (such as activities) to bind to the service, send requests, receive responses, and even perform interprocess communication (IPC). A bound service typically lives only while it serves another application component and does not run in the background indefinitely.

 

这里以扩展Binder类为例讲解如何创建Bound Services.

 

Binder

extends Object
implements IBinder

java.lang.Object
↳	android.os.Binder

很明显，Binder实现了IBinder这接口。

 

通过扩展Binder类创建Bound Service的步骤如下：

a、在Service类中，创建一个Binder实例，包含客户端能调用的公共方法，返回当前服务对象;

b、在onBind()方法中返回Binder实例;

c、在客户端,从onServiceConnected方法中获得Binder实例。

 

工程目录结构：

运行界面：

源代码：

MainActivity.java:

 

package com.service.activity;

import com.service.activity.BinderService.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.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity {
    private Button btnStartService;
    private Button btnstopService;
    private boolean isConnected = false;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        btnStartService = (Button)findViewById(R.id.btnStartService);
        btnStartService.setOnClickListener(listener);
        btnstopService = (Button)findViewById(R.id.btnStopService);
        btnstopService.setOnClickListener(listener);
    }

    private OnClickListener listener = new OnClickListener() {

        @Override
        public void onClick(View v) {
            switch (v.getId()) {
            case R.id.btnStartService:
                funBindService();
                break;
            case R.id.btnStopService:
                funUnBindService();
                break;
            default:
                break;
            }
        }
        private void funBindService() {
            Intent intent = new Intent(MainActivity.this, BinderService.class);
            bindService(intent, conn, Context.BIND_AUTO_CREATE);
        }

        private void funUnBindService() {
            if(isConnected == true){
                unbindService(conn);
            }
        }

    };

    private ServiceConnection conn = new ServiceConnection() {

        @Override
        public void onServiceDisconnected(ComponentName name) {
            isConnected = false;
        }
        //与Service连接时被回调
        @Override
        public void onServiceConnected(ComponentName name, IBinder iBinder) {
            MyBinder myBinder = (MyBinder)iBinder;
            BinderService service = myBinder.getService();
            service.MyMethod();
            isConnected = true;
        }
    };
}

BinderService.java

 

package com.service.activity;

import android.app.Service;
import android.content.Intent;
import android.os.Binder;
import android.os.IBinder;
import android.util.Log;

public class BinderService extends Service{
    private static final String TAG = "BinderService";
    private MyBinder myBinder = new MyBinder();
    //内部类，扩展自Binder类
    public class MyBinder extends Binder{
        public BinderService getService(){
            return BinderService.this;
        }
    }
    //复写onBind方法，并且返回IBinder的实现类
    @Override
    public IBinder onBind(Intent intent) {
        Log.i(TAG, "onBind");
        return myBinder;
    }

    public void MyMethod(){
        Log.i(TAG, "MyMethod");
    }

    @Override
    public boolean onUnbind(Intent intent) {
        Log.i(TAG, "onUnbind");
        return super.onUnbind(intent);
    }

    @Override
    public void onDestroy() {
        Log.i(TAG, "onDestroy");
        super.onDestroy();
    }

}

 

 

main.xml:

 

 

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="启动service"
        android:id="@+id/btnStartService"/>
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="停止service"
        android:id="@+id/btnStopService"/>

</LinearLayout>

点击启动service,日志输出信息：

 

点击停止service,日志输出信息：