Android之Service学习篇二：Service启动方式之boundService
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 Objectimplements IBinder
| java.lang.Object | |
| ↳ | android.os.Binder |
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：
