android学习笔记(11)Bound Services初步

亦凉 2022-08-04 14:45 352阅读 0赞

这节课很有难度，要勤奋学习!!

bound service 允许其它的组件(比如Activities)绑定到这个services上,可以发送请求,也可以接收请求,甚至进行进程间的通话,bound service仅仅在服务于其它组件时存在,不能独自无限期在后台运行.  
**一,创建Bound Services**  
当创建一个能提供绑定报务功能的服务时,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进行交互,在Adroid中有三种方式定义:  
1,扩展Binder类  
2,使用Messenger  
3,使用AIDL(Android Interface Definition Language)  
**二,通过扩展Binder类创建Bound Services**  
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

**三，源码**

BinderService.java

package com.example1.servicedemo;
    
    import android.app.Service;
    import android.content.Intent;
    import android.os.IBinder;
    import android.util.Log;
    
    public class BinderService extends Service {
    
    	private static final String TAG = "BinderService";
    	private MyBinder binder = new MyBinder();//a,在Service类中,创建一个Binder实例
    	public class MyBinder extends BinderService
    	{
    		public BinderService getService()
    		{
    			return BinderService.this;
    		}
    	}
    	@Override
    	public IBinder onBind(Intent intent) {
    		
    		return (IBinder) binder;//返回当前服务对象
    	}
    	public void MyMethod()//包含客户端能调用的公共方法
    	{
    
    		Log.i(TAG, "MyMethod");
    	}
    
    }

BinderActivity.java

package com.example1.servicedemo;
    
    import com.example1.servicedemo.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 BinderActivity extends Activity {
    	private Button btnbinderservicestart;
    	private Button btnbinderservicestop;
    	private Boolean isConnected = false;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.binder);
            btnbinderservicestart=(Button)findViewById(R.id.btnbinderservicestart);
            btnbinderservicestop=(Button)findViewById(R.id.btnbinderservicestop);
            btnbinderservicestart.setOnClickListener(listener);
            btnbinderservicestop.setOnClickListener(listener);
    }
        private OnClickListener listener = new OnClickListener() {
    		
    		@Override
    		public void onClick(View v) {
    			// TODO Auto-generated method stub
    			switch (v.getId()) {
    			case R.id.btnbinderservicestart:
    				bindService();
    				break;
    			case R.id.btnbinderservicestop:
    				unbind();
    				break;
    			default:
    				break;
    			}	
    		}
    
    
    	};
    	private void unbind() {
    	if (isConnected) {
    		unbindService(conn);
    	}
    		
    	}
    
    	private void bindService() {
    		Intent intent = new Intent(BinderActivity.this,BinderService.class);
    		bindService(intent, conn, Context.BIND_AUTO_CREATE);
    		
    	}
    	
    	private ServiceConnection conn = new ServiceConnection() {
    		
    		@Override
    		public void onServiceDisconnected(ComponentName arg0) {
    			isConnected=false;
    			
    		}
    		
    		@Override
    		public void onServiceConnected(ComponentName arg0, IBinder binder) {
    			MyBinder myBinder = (MyBinder)binder;
    			BinderService service = myBinder.getService();
    			service.MyMethod();
    			isConnected=true;
    		}
    	};
    }

XML文件

<?xml version="1.0" encoding="utf-8"?>
    <manifest xmlns:android="http://schemas.android.com/apk/res/android"
        package="com.example1.servicedemo"
        android:versionCode="1"
        android:versionName="1.0" >
    
        <uses-sdk
            android:minSdkVersion="8"
            android:targetSdkVersion="18" />
    
        <application
            android:allowBackup="true"
            android:icon="@drawable/ic_launcher"
            android:label="@string/app_name"
            android:theme="@style/AppTheme" >
            <activity
                android:name="com.example1.servicedemo.MainActivity"
                android:label="@string/app_name" >
               
            </activity>
            
                    <activity
                android:name="com.example1.servicedemo.BinderActivity"
                android:label="@string/app_name" >
                <intent-filter>
                    <action android:name="android.intent.action.MAIN" />
    
                    <category android:name="android.intent.category.LAUNCHER" />
                </intent-filter>
            </activity>
              <service android:name=".ExampleService"/>
            <service android:name=".BinderService"/>
        </application>
    
    </manifest>