Service代码示例

 

 1 package com.homily.training.service;
 2 
 3 import android.app.Service;
 4 import android.content.Intent;
 5 import android.os.Binder;
 6 import android.os.IBinder;
 7 import android.support.annotation.Nullable;
 8 import android.util.Log;
 9 
10 import com.homily.training.test.service.ICallbackResult;
11 
12 /**
13  * Created by Rubert on 2016/7/6.
14  */
15 public class BindService extends Service{
16 
17     private final static String TAG = BindService.class.getSimpleName();
18 
19     private MBinder mMBinder;
20     private ICallbackResult mICallbackResult;
21     private boolean unBindTarget = false;
22 
23 
24     @Nullable
25     @Override
26     public IBinder onBind(Intent intent) {
27         Log.i(TAG, "============onBind==================");
28         return mMBinder;
29     }
30     @Override
31     public void onCreate() {
32         super.onCreate();
33         Log.i(TAG, "============onCreate==================");
34         mMBinder = new MBinder();
35     }
36 
37     @Override
38     public int onStartCommand(Intent intent, int flags, int startId) {
39         Log.i(TAG, "============onStartCommand==================");
40         return super.onStartCommand(intent, flags, startId);
41     }
42 
43     @Override
44     public void onDestroy() {
45         unBindTarget = true;
46         super.onDestroy();
47         Log.i(TAG, "============onDestroy==================");
48     }
49 
50     @Override
51     public boolean onUnbind(Intent intent) {
52         Log.i(TAG, "============onUnbind==================");
53         unBindTarget = true;//该处代码需要这么写是因为，Service中开启了线程。如果该Service直接onUnbind了，但是线程没有停止，并且如果再次bind该Service时，程序会再次重新实例化一个线程，并之前的线程也会一直运行下去，除非该app销毁。
54         return super.onUnbind(intent);
55     }
56 
57     public class MBinder extends Binder {
58         public void start(){
59             Log.i(TAG, "============MBinder-start==================");
60             new Thread(new Runnable() {
61                 @Override
62                 public void run() {
63 
64                     while (true) {
65                         if(unBindTarget) {
66                             break;
67                         }
68                         Log.i(TAG, Thread.currentThread().getName() + "============MBinder-start-run==================");
69                         mICallbackResult.OnBackResult(null);
70                         try {
71                             Thread.currentThread().sleep(5000);
72                         } catch (InterruptedException e) {
73                             e.printStackTrace();
74                         }
75                     }
76                 }
77             }).start();
78         }
79 
80         public void bind(ICallbackResult result) {
81             mICallbackResult = result;
82         }
83 
84     }
85 
86 
87 }

 

 1 package com.homily.training.service;
 2 
 3 import android.app.Service;
 4 import android.content.Intent;
 5 import android.os.IBinder;
 6 import android.support.annotation.Nullable;
 7 import android.util.Log;
 8 
 9 /**
10  * Created by Rubert on 2016/7/6.
11  */
12 public class StartService extends Service{
13 
14     private final static String TAG = StartService.class.getSimpleName();
15 
16     @Nullable
17     @Override
18     public IBinder onBind(Intent intent) {
19         Log.i(TAG, "============onBind==================");
20         return null;
21     }
22 
23     @Override
24     public void onCreate() {
25         super.onCreate();
26         Log.i(TAG, "============onCreate==================");
27     }
28 
29     @Override
30     public int onStartCommand(Intent intent, int flags, int startId) {
31         Log.i(TAG, "============onStartCommand==================");
32         return super.onStartCommand(intent, flags, startId);
33     }
34 
35     @Override
36     public void onDestroy() {
37         super.onDestroy();
38         Log.i(TAG, "============onDestroy==================");
39     }
40 
41     @Override
42     public boolean onUnbind(Intent intent) {
43         Log.i(TAG, "============onUnbind==================");
44         return super.onUnbind(intent);
45     }
46 }

 

 1 package com.homily.training.test.service;
 2 
 3 import android.app.Activity;
 4 import android.content.ComponentName;
 5 import android.content.Context;
 6 import android.content.Intent;
 7 import android.content.ServiceConnection;
 8 import android.os.Binder;
 9 import android.os.Bundle;
10 import android.os.IBinder;
11 import android.util.Log;
12 import android.view.View;
13 import android.widget.Button;
14 
15 import com.homily.training.R;
16 import com.homily.training.service.BindService;
17 import com.homily.training.service.StartService;
18 
19 /**
20  * Created by Rubert on 2016/7/6.
21  * 主要验证startService 启动后再次启动；以及bindService绑定后，解绑再次绑定的情况。
22  */
23 public class ServiceMainAct extends Activity implements View.OnClickListener{
24 
25     private final static String TAG = ServiceMainAct.class.getSimpleName();
26 
27     Button startServiceBtn;
28     Button closeServiceBtn;
29     Button bindServiceBtn;
30     Button unbindServiceBtn;
31     BindService.MBinder mMBinder;
32     boolean IsBinder = false;
33 
34     @Override
35     protected void onCreate(Bundle savedInstanceState) {
36         super.onCreate(savedInstanceState);
37         setContentView(R.layout.service_layout);
38         startServiceBtn = (Button)findViewById(R.id.startService);
39         closeServiceBtn = (Button)findViewById(R.id.closeService);
40         bindServiceBtn = (Button)findViewById(R.id.binService);
41         unbindServiceBtn = (Button)findViewById(R.id.unbinService);
42 
43         startServiceBtn.setOnClickListener(this);
44         closeServiceBtn.setOnClickListener(this);
45         bindServiceBtn.setOnClickListener(this);
46         unbindServiceBtn.setOnClickListener(this);
47     }
48 
49 
50 
51     ServiceConnection mConnection = new ServiceConnection(){
52         @Override
53         public void onServiceConnected(ComponentName componentName, IBinder iBinder) {
54             Log.i(TAG, "=============onServiceConnected==================");
55             mMBinder = (BindService.MBinder)iBinder;
56             mMBinder.bind(mICallbackResult);
57             mMBinder.start();
58             IsBinder = true;
59         }
60         @Override
61         public void onServiceDisconnected(ComponentName componentName) {
62             Log.i(TAG, "=============onServiceDisconnected==================");
63             IsBinder = false;
64         }
65     };
66 
67     ICallbackResult mICallbackResult = new ICallbackResult(){
68         @Override
69         public void OnBackResult(Object result) {
70             Log.i(TAG, "=============result==================");
71         }
72     };
73 
74     @Override
75     public void onClick(View view) {
76         switch (view.getId()) {
77             case R.id.startService:
78                 Intent sintent = new Intent(ServiceMainAct.this, StartService.class);
79                 startService(sintent);
80                 break;
81             case R.id.closeService:
82                 Intent cintent = new Intent(ServiceMainAct.this, StartService.class);
83                 stopService(cintent);
84                 break;
85             case R.id.binService:
86                 Intent service = new Intent(ServiceMainAct.this, BindService.class);
87                 bindService(service, mConnection, Context.BIND_AUTO_CREATE);
88                 break;
89             case R.id.unbinService:
90                 if(mConnection != null && IsBinder)
91                 unbindService(mConnection);
92                 break;
93         }
94 
95     }
96 
97 
98 
99 }

 

1 package com.homily.training.test.service;
2 
3 /**
4  * Created by Rubert on 2016/7/6.
5  */
6 public interface ICallbackResult {
7     void OnBackResult(Object result);
8 }

 

<application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >

        <service android:name="com.homily.training.service.StartService" />
        <service android:name="com.homily.training.service.BindService" />
    
<activity android:name=".test.service.ServiceMainAct">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
</application>

 

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     android:layout_width="match_parent"
 4     android:layout_height="match_parent"
 5     android:orientation="vertical"
 6     >
 7 
 8     <Button
 9         android:id="@+id/startService"
10         android:layout_width="match_parent"
11         android:layout_height="wrap_content"
12         android:text="startService"
13         />
14     <Button
15         android:id="@+id/closeService"
16         android:layout_width="match_parent"
17         android:layout_height="wrap_content"
18         android:text="closeService"
19         />
20 
21     <Button
22         android:id="@+id/binService"
23         android:layout_width="match_parent"
24         android:layout_height="wrap_content"
25         android:text="binService"
26         />
27     <Button
28         android:id="@+id/unbinService"
29         android:layout_width="match_parent"
30         android:layout_height="wrap_content"
31         android:text="unbinService"
32         />
33 
34 </LinearLayout>

 

Android开发的过程中，每次调用startService(Intent)的时候，都会调用该Service对象的onStartCommand(Intent,int,int)方法，然后在onStartCommand方法中做一些处理。然后我们注意到这个函数有一个int的返回值，这篇文章就是简单地讲讲int返回值的作用。

从Android官方文档中，我们知道onStartCommand有4种返回值：

 

START_STICKY：如果service进程被kill掉，保留service的状态为开始状态，但不保留递送的intent对象。随后系统会尝试重新创建service，由于服务状态为开始状态，所以创建服务后一定会调用onStartCommand(Intent,int,int)方法。如果在此期间没有任何启动命令被传递到service，那么参数Intent将为null。

 

START_NOT_STICKY：“非粘性的”。使用这个返回值时，如果在执行完onStartCommand后，服务被异常kill掉，系统不会自动重启该服务。

 

START_REDELIVER_INTENT：重传Intent。使用这个返回值时，如果在执行完onStartCommand后，服务被异常kill掉，系统会自动重启该服务，并将Intent的值传入。

 

START_STICKY_COMPATIBILITY： START_STICKY的兼容版本，但不保证服务被kill后一定能重启。