Android 的 Service 入门，androidservice

Android 的 Service 入门，androidservice

如果把Activity比喻为前台程序，那么Service就是后台程序，Service的整个生命周期都只会在后台执行。Service跟 Activity一样也由Intent调用。在工程里想要添加一个Service，先新建继承Service的类，然后到 AndroidManifest.xml -> Application ->Application Nodes中的Service标签中添加。

Service要由Activity通过startService 或者 bindService来启动，Intent负责传递参数。

startService与bindService都可以启动Service，那么它们之间有什么区别呢？它们两者的区别就是使Service的周期改变。由 startService启动的Service必须要有stopService来结束Service，不调用stopService则会造成 Activity结束了而Service还运行着。bindService启动的Service可以由unbindService来结束，也可以在 Activity结束之后(onDestroy)自动结束。

1.[图片] 程序运行截图

2.main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
	android:orientation="vertical" android:layout_width="fill_parent"
	android:layout_height="fill_parent">
	<Button android:layout_width="wrap_content"
		android:layout_height="wrap_content" android:id="@+id/btnStartMyService"
		android:text="StartMyService"></Button>
	<Button android:layout_width="wrap_content"
		android:layout_height="wrap_content" android:id="@+id/btnStopMyService"
		android:text="StopMyService"></Button>
	<Button android:layout_width="wrap_content"
		android:layout_height="wrap_content" android:id="@+id/btnBindMyService"
		android:text="BindMyService"></Button>
	<Button android:layout_width="wrap_content"
		android:layout_height="wrap_content" android:id="@+id/btnUnbindMyService"
		android:text="UnbindMyService"></Button>
	<Button android:layout_width="wrap_content"
		android:layout_height="wrap_content" android:id="@+id/btnExit"
		android:text="退出程序"></Button>
</LinearLayout>

3.TestService.java

package com.testService;

import android.app.Activity;
import android.app.Service;
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 android.widget.Button;

public class TestService extends Activity {
    Button btnStartMyService,btnStopMyService,btnBindMyService,btnUnbindMyService,btnExit;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        btnStartMyService=(Button)this.findViewById(R.id.btnStartMyService);
        btnStartMyService.setOnClickListener(new ClickEvent());
        
        btnStopMyService=(Button)this.findViewById(R.id.btnStopMyService);
        btnStopMyService.setOnClickListener(new ClickEvent());
        
        btnBindMyService=(Button)this.findViewById(R.id.btnBindMyService);
        btnBindMyService.setOnClickListener(new ClickEvent());
        
        btnUnbindMyService=(Button)this.findViewById(R.id.btnUnbindMyService);
        btnUnbindMyService.setOnClickListener(new ClickEvent()); 
        
        btnExit=(Button)this.findViewById(R.id.btnExit);
        btnExit.setOnClickListener(new ClickEvent());
    }
    @Override
    public void onDestroy()
    {
    	super.onDestroy();
    	Log.e("Activity","onDestroy");
    }
    
    private ServiceConnection _connection = new ServiceConnection() {  
		@Override
		public void onServiceConnected(ComponentName arg0, IBinder arg1) {
			// TODO Auto-generated method stub
		}

		@Override
		public void onServiceDisconnected(ComponentName name) {
			// TODO Auto-generated method stub
		}  
    };  
    class ClickEvent implements View.OnClickListener{

		@Override
		public void onClick(View v) {
			Intent intent=new Intent(testService.this,MyService.class);
			if(v==btnStartMyService){
				testService.this.startService(intent);
			}
			else if(v==btnStopMyService){
				testService.this.stopService(intent);
			}
			else if(v==btnBindMyService){
				testService.this.bindService(intent, _connection, Service.BIND_AUTO_CREATE);
			}
			else if(v==btnUnbindMyService){
				if(MyService.ServiceState=="onBind")//Service绑定了之后才能解绑
					testService.this.unbindService(_connection);
			}
			else if(v==btnExit)
			{
				testService.this.finish();
			}
			
		}
    	
    }
}

4.MyService.java

package com.testService;

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

public class MyService extends Service {
	static public String ServiceState="";
	@Override
	public IBinder onBind(Intent arg0) {
		Log.e("Service", "onBind");
		ServiceState="onBind";
		return null;
	}
	@Override
	public boolean onUnbind(Intent intent){
		super.onUnbind(intent);
		Log.e("Service", "onUnbind");
		ServiceState="onUnbind";
		return false;
		
	}
	@Override
	public void onCreate(){
		super.onCreate();
		Log.e("Service", "onCreate");
		ServiceState="onCreate";
	}
	@Override
	public void onDestroy(){
		super.onDestroy();
		Log.e("Service", "onDestroy");
		ServiceState="onDestroy";
	}
	@Override
	public void onStart(Intent intent,int startid){
		super.onStart(intent, startid);
		Log.e("Service", "onStart");
		ServiceState="onStart";
	}

}