Service生命周期浅析 4000

一、startService方式启动

   
第一次调用startService:onCreate——onStartCommand——onStart;

    之后调用startService:onStartCommand——onStart;
    调用stopService:onDestroy

二、bindService方式启动

    第一次调用bindService:onCreate——onBind
    多次调用bindService:无效，只能调用一次
    调用unbindService:onUnbind——onDestroy
    再次调用unbindService:报错退出，如下：

           03-03 13:50:51.017 16293-16293/com.winter.activitylife E/AndroidRuntime: FATAL EXCEPTION: main
           03-03 13:50:51.017 16293-16293/com.winter.activitylife E/AndroidRuntime: Process: com.winter.activitylife, PID: 16293

           03-03 13:50:51.017 16293-         16293/com.winter.activitylife E/AndroidRuntime: java.lang.IllegalArgumentException: Service not registered: com.winter.activitylife.MainActivity$1@13f07343

           03-03 13:50:51.017 16293-16293/com.winter.activitylife E/AndroidRuntime:     at android.app.LoadedApk.forgetServiceDispatcher(LoadedApk.java:1031)

           03-03 13:50:51.017 16293-16293/com.winter.activitylife E/AndroidRuntime:     at android.app.ContextImpl.unbindService(ContextImpl.java:1817)

           03-03 13:50:51.017 16293-16293/com.winter.activitylife E/AndroidRuntime:     at android.content.ContextWrapper.unbindService(ContextWrapper.java:551)

           03-03 13:50:51.017 16293-16293/com.winter.activitylife E/AndroidRuntime:     at com.winter.activitylife.MainActivity.onClick(MainActivity.java:102)
           03-03 13:50:51.017 16293-16293/com.winter.activitylife E/AndroidRuntime:     at android.view.View.performClick(View.java:4783)

           03-03 13:50:51.017 16293-16293/com.winter.activitylife E/AndroidRuntime:     at android.view.View$PerformClick.run(View.java:19887)
           03-03 13:50:51.017 16293-16293/com.winter.activitylife E/AndroidRuntime:     at android.os.Handler.handleCallback(Handler.java:739)
           03-03 13:50:51.017 16293-16293/com.winter.activitylife E/AndroidRuntime:     at android.os.Handler.dispatchMessage(Handler.java:95)
           03-03 13:50:51.017 16293-16293/com.winter.activitylife E/AndroidRuntime:     at android.os.Looper.loop(Looper.java:135)
           03-03 13:50:51.017 16293-16293/com.winter.activitylife E/AndroidRuntime:     at android.app.ActivityThread.main(ActivityThread.java:5283)
           03-03 13:50:51.017 16293-16293/com.winter.activitylife E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Native Method)
           03-03 13:50:51.017 16293-16293/com.winter.activitylife E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Method.java:372)
           03-03 13:50:51.017 16293-16293/com.winter.activitylife E/AndroidRuntime:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:908)
           03-03 13:50:51.017 16293-16293/com.winter.activitylife E/AndroidRuntime:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:703)

三、两种启动方式一起用

   
1.startService——onCreate——onStartCommand——onStart——bindService——onBind——stopService——null——
unbindService——onUnbind——onDestroy
    2.startService——onCreate——onStartCommand——onStart——bindService——onBind——unbindService——onUnbind——
stopService——onDestroy
   
3.bindService——onCreate——onBind——startService——onStartCommand——onStart——unbindService——onUnbind——
stopService——onDestroy
   
4.bindService——onCreate——onBind——startService——onStartCommand——onStart——stopService——null——
unbindService——onUnbind——onDestroy
   
（null代表没有经历任何生命周期方法）

四、与Activity生命周期的关联

 
  1.startService方式启动

 
  如果一个Activity用startService的方式启动Service，而且在Activity生命结束（onDestroy）之前没有调用stopService方法，Service不会结束，当Activity再次被打开，并重新调用starttService方法时，Service的onCreate方法不会被执行，只会执行nStartCommand——onStart方法。

 
  2.bindService方式启动

 
  如果一个Activity用bindService的方式启动Service，而且在Activity生命结束（onDestroy）之前没有调用unbindService方法，Activity的onDestroy方法执行后会报错，表明有连接泄漏并且会继续执行Service的onUnbind——onDestroy方法，现象如下：
           03-03 14:16:49.427 17091-17091/com.winter.activitylife E/MainActivity: onCreate
           03-03 14:16:49.427 17091-17091/com.winter.activitylife E/MainActivity: onStart
           03-03 14:16:49.437 17091-17091/com.winter.activitylife E/MainActivity: onResume
           03-03 14:16:55.327 17091-17091/com.winter.activitylife E/MyService: onCreate
           03-03 14:16:55.327 17091-17091/com.winter.activitylife E/MyService: onBind
           03-03 14:17:00.247 17091-17091/com.winter.activitylife E/MainActivity: onPause
           03-03 14:17:00.507 17091-17091/com.winter.activitylife E/MainActivity: onStop
           03-03 14:17:00.507 17091-17091/com.winter.activitylife E/MainActivity: onDestroy
           03-03 14:17:00.537 17091-17091/com.winter.activitylife E/ActivityThread:
                                                                  Activity com.winter.activitylife.MainActivity has leaked ServiceConnection
                                                                  com.winter.activitylife.MainActivity$1@172b2663 that was originally bound here
           03-03 14:17:00.537 17091-17091/com.winter.activitylife E/ActivityThread:
                                                                  android.app.ServiceConnectionLeaked: Activity com.winter.activitylife.MainActivity has leaked ServiceConnection 
                                                                  com.winter.activitylife.MainActivity$1@172b2663 that was originally bound here
           03-03 14:17:00.537 17091-17091/com.winter.activitylife E/ActivityThread:     at android.app.LoadedApk$ServiceDispatcher.<init>(LoadedApk.java:1079)
           03-03 14:17:00.537 17091-17091/com.winter.activitylife E/ActivityThread:     at android.app.LoadedApk.getServiceDispatcher(LoadedApk.java:973)
           03-03 14:17:00.537 17091-17091/com.winter.activitylife E/ActivityThread:     at android.app.ContextImpl.bindServiceCommon(ContextImpl.java:1783)
           03-03 14:17:00.537 17091-17091/com.winter.activitylife E/ActivityThread:     at android.app.ContextImpl.bindService(ContextImpl.java:1766)
           03-03 14:17:00.537 17091-17091/com.winter.activitylife E/ActivityThread:     at android.content.ContextWrapper.bindService(ContextWrapper.java:539)
           03-03 14:17:00.537 17091-17091/com.winter.activitylife E/ActivityThread:     at com.winter.activitylife.MainActivity.onClick(MainActivity.java:99)
           03-03 14:17:00.537 17091-17091/com.winter.activitylife E/ActivityThread:     at android.view.View.performClick(View.java:4783)
           03-03 14:17:00.537 17091-17091/com.winter.activitylife E/ActivityThread:     at android.view.View$PerformClick.run(View.java:19887)
           03-03 14:17:00.537 17091-17091/com.winter.activitylife E/ActivityThread:     at android.os.Handler.handleCallback(Handler.java:739)
           03-03 14:17:00.537 17091-17091/com.winter.activitylife E/ActivityThread:     at android.os.Handler.dispatchMessage(Handler.java:95)
           03-03 14:17:00.537 17091-17091/com.winter.activitylife E/ActivityThread:     at android.os.Looper.loop(Looper.java:135)
           03-03 14:17:00.537 17091-17091/com.winter.activitylife E/ActivityThread:     at android.app.ActivityThread.main(ActivityThread.java:5283)
           03-03 14:17:00.537 17091-17091/com.winter.activitylife E/ActivityThread:     at java.lang.reflect.Method.invoke(Native Method)
           03-03 14:17:00.537 17091-17091/com.winter.activitylife E/ActivityThread:     at java.lang.reflect.Method.invoke(Method.java:372)
           03-03 14:17:00.537 17091-17091/com.winter.activitylife E/ActivityThread:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:908)
           03-03 14:17:00.537 17091-17091/com.winter.activitylife E/ActivityThread:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:703)
           03-03 14:17:00.537 17091-17091/com.winter.activitylife E/MyService: onUnbind
           03-03 14:17:00.537 17091-17091/com.winter.activitylife E/MyService: onDestroy

    打印调用堆栈显示，onUnbind方法是被ActivityThread调用的：

           03-03 14:27:05.857 13006-13006/com.winter.activitylife W/System.err: java.lang.Exception:
this is a log
           03-03 14:27:05.857 13006-13006/com.winter.activitylife W/System.err:     at com.winter.activitylife.MyService.onUnbind(MyService.java:51)
           03-03 14:27:05.857 13006-13006/com.winter.activitylife W/System.err:     at android.app.ActivityThread.handleUnbindService(ActivityThread.java:2834)
           03-03 14:27:05.857 13006-13006/com.winter.activitylife W/System.err:     at android.app.ActivityThread.access$2000(ActivityThread.java:154)
           03-03 14:27:05.857 13006-13006/com.winter.activitylife W/System.err:     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1408)
           03-03 14:27:05.857 13006-13006/com.winter.activitylife W/System.err:     at android.os.Handler.dispatchMessage(Handler.java:102)
           03-03 14:27:05.857 13006-13006/com.winter.activitylife W/System.err:     at android.os.Looper.loop(Looper.java:135)
           03-03 14:27:05.857 13006-13006/com.winter.activitylife W/System.err:     at android.app.ActivityThread.main(ActivityThread.java:5283)
           03-03 14:27:05.857 13006-13006/com.winter.activitylife W/System.err:     at java.lang.reflect.Method.invoke(Native
Method)
           03-03 14:27:05.857 13006-13006/com.winter.activitylife W/System.err:     at java.lang.reflect.Method.invoke(Method.java:372)
           03-03 14:27:05.857 13006-13006/com.winter.activitylife W/System.err:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:908)
           03-03 14:27:05.857 13006-13006/com.winter.activitylife W/System.err:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:703)

    当Activity再次被打开，并调用bindService方法时，Service会被重新创建并绑定：bindService——onCreate——onBind

五、Service的onRebind方法何时被调用？

    打开Service.java类，查看onRebind方法的注释：

    /**
     * Called when new clients have connected to the service, after it had

     * previously been notified that all had disconnected in its
     * {@link
#onUnbind}. This will only be called if the implementation

     * of {@link
#onUnbind} was overridden to return true.
     * 
     *
@param
intent
The Intent that was used to bind to this service,
     * as given to {@link
android.content.Context#bindService
     * Context.bindService}. Note that any extras that were included with
     * the Intent at that point will
<em>not</em>
be seen here.
     */
    public void
onRebind(Intent intent) {

    }
    两点：第一，Service被连接（connected），并且已经调用onUnbind解开了连接；第二onUnbind方法被重写，并且返回true。