5.Android Service

来源：互联网发布：win7 64位php环境搭建编辑：程序博客网时间：2024/05/04 06:05

上次介绍了Activity以及Intent的使用，这次就介绍Android 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。先贴出本应用运行截图：

startService

本文主要讲解Service的调用，以及其生命周期。

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

stopService

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

unbindService

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。

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

Activity.finish()

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

自动unbindService

main.xml代码

?
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
<?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:id="@+id/btnStartMyService"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="StartMyService"
        />
    <Button
        android:id="@+id/btnStopMyService"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="StopMyService"
        />
    <Button
        android:id="@+id/btnBindMyService"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="BindMyService"
        />
    <Button
        android:id="@+id/btnUnbindMyService"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="UnbindMyService"
        />
    <Button
        android:id="@+id/btnExit"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="退出程序"
        />
</LinearLayout>

testService.java的源码

?
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
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

?
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
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";
    }
 
}