Android入门教程(二十八)------之Service

本文来自http://blog.csdn.net/hellogv/ ，引用必须注明出处！

        上次介绍了Activity以及Intent的使用，这次就介绍Service，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。先贴出本文程序运行截图：

 

本文主要讲解Service的调用，以及其生命周期。

上图是startService之后再stopService的Service状态变化。

上图是bindService之后再unbindService的Service状态变化。

       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。

 上图是startService之后再Activity.finish()的Service状态变化，Service还在跑着。

上图是bindService之后再Activity.finish()的Service状态变化，Service最后自动unbindService。

main.xml代码：

<?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>

<?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>

 

testService.java的源码：

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();
            }

        }

    }
}

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(); } } } }

 

MyService.java的源码：

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";
    }

}