• Android service几个问题

    Android service几个问题

    记录service二三事

    问题1

    在一些系统中使用**startService可以启动服务，bindService无法启动服务**

    进程A bindService 服务端的进程B。
    进程B没启动，进程A bindService无效
    进程B已启动，进程A bindService 成功

    原因：
    android7 新增了一个 关联启动（StartUp）权限，默认没有开启，所以Service进程B就没办法 被进程A启动。

    解决：
    打开设置----》应用列表—》选择服务端的应用—》权限----》开启 关联启动

    问题2

    同一个应用多次绑定Service，onServiceConnect会执行几次？Service的函数会执行哪些？

    • 同一个ServiceConnection 不会回调多次
    • 只有第一次bindService会执行Service的onCreate方法
    • 同一个进程bind服务，Service只执行一次onBind方法
    • 同一个ServiceConnection只会回调一次onServiceConnet，不同ServiceConnection会回调一次onServiceConnect
    07-12 17:38:06.443 14805 14805 D ServiceBinderStatusTest: onClick: bind_service 
07-12 17:38:06.560 14981 14981 D ServiceBinderStatusTest: onCreate: 
07-12 17:38:06.561 14981 14981 D ServiceBinderStatusTest: onBind: 1
07-12 17:38:06.561 14805 14805 D ServiceBinderStatusTest: onServiceConnected: 
07-12 17:38:08.312 14805 14805 D ServiceBinderStatusTest: onClick: bind_service2
07-12 17:38:08.313 14805 14805 D ServiceBinderStatusTest: onClick: bindService true
07-12 17:38:08.313 14805 14805 D ServiceBinderStatusTest: onServiceConnected 2: 
07-12 17:38:14.069 14805 14805 D ServiceBinderStatusTest: onClick: bind_service 
07-12 17:38:15.235 14805 14805 D ServiceBinderStatusTest: onClick: bind_service 
07-12 17:38:17.200 14805 14805 D ServiceBinderStatusTest: onClick: bind_service2
07-12 17:38:17.203 14805 14805 D ServiceBinderStatusTest: onClick: bindService true
07-12 17:38:17.203 14805 14805 D ServiceBinderStatusTest: onServiceConnected 2: 
07-12 17:38:26.685 14805 14805 D ServiceBinderStatusTest: onClick: bind_service2
07-12 17:38:26.689 14805 14805 D ServiceBinderStatusTest: onClick: bindService true
07-12 17:38:26.694 14805 14805 D ServiceBinderStatusTest: onServiceConnected 2: 
07-12 17:38:28.203 14805 14805 D ServiceBinderStatusTest: onClick: bind_service 
07-12 17:38:33.446 14805 14805 D ServiceBinderStatusTest: onClick: bind_service2
07-12 17:38:33.450 14805 14805 D ServiceBinderStatusTest: onClick: bindService true
07-12 17:38:33.452 14805 14805 D ServiceBinderStatusTest: onServiceConnected 2:

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    问题3

    生命周期

    • startService -> stopService

      07-12 17:56:27.928 26644 26644 D ServiceBinderStatusTest: onClick: start_service
07-12 17:56:27.935 14981 14981 D ServiceBinderStatusTest: onCreate: 
07-12 17:56:27.946 14981 14981 D ServiceBinderStatusTest: onStartCommand: 
07-12 17:56:27.946 14981 14981 D ServiceBinderStatusTest: onStart: 

07-12 17:56:37.871 26644 26644 D ServiceBinderStatusTest: onClick: stop_service
07-12 17:56:37.877 14981 14981 D ServiceBinderStatusTest: onDestroy

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    • bindService -> unbindService

      07-12 18:08:43.871  2672  2672 D ServiceBinderStatusTest: onClick: bind_service 
07-12 18:08:43.877 14981 14981 D ServiceBinderStatusTest: onCreate: 
07-12 18:08:43.878 14981 14981 D ServiceBinderStatusTest: onBind: 1
07-12 18:08:43.879  2672  2672 D ServiceBinderStatusTest: onServiceConnected: 
07-12 18:08:45.528  2672  2672 D ServiceBinderStatusTest: onClick: unbindService
07-12 18:08:45.531 14981 14981 D ServiceBinderStatusTest: onUnbind: 1
07-12 18:08:45.531 14981 14981 D ServiceBinderStatusTest: onDestroy: 


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    • bindService -> startService -> unbindService -> stopService

      07-12 18:09:56.550  3414  3414 D ServiceBinderStatusTest: onClick: bind_service 
07-12 18:09:56.554 14981 14981 D ServiceBinderStatusTest: onCreate: 
07-12 18:09:56.554 14981 14981 D ServiceBinderStatusTest: onBind: 1
07-12 18:09:56.559  3414  3414 D ServiceBinderStatusTest: onServiceConnected: 
07-12 18:09:59.734  3414  3414 D ServiceBinderStatusTest: onClick: start_service
07-12 18:09:59.740 14981 14981 D ServiceBinderStatusTest: onStartCommand: 
07-12 18:09:59.740 14981 14981 D ServiceBinderStatusTest: onStart: 
07-12 18:10:06.191  3414  3414 D ServiceBinderStatusTest: onClick: unbindService
07-12 18:10:06.199 14981 14981 D ServiceBinderStatusTest: onUnbind: 1
07-12 18:10:08.281  3414  3414 D ServiceBinderStatusTest: onClick: stop_service
07-12 18:10:08.287 14981 14981 D ServiceBinderStatusTest: onDestroy: 

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      unbindService 和 stopService都执行之后才会调用onDestroy

    • startService -> bindService -> unbindService -> stopService

      07-12 18:11:12.005  3414  3414 D ServiceBinderStatusTest: onClick: start_service
07-12 18:11:12.010 14981 14981 D ServiceBinderStatusTest: onCreate: 
07-12 18:11:12.010 14981 14981 D ServiceBinderStatusTest: onStartCommand: 
07-12 18:11:12.010 14981 14981 D ServiceBinderStatusTest: onStart: 
07-12 18:11:13.606  3414  3414 D ServiceBinderStatusTest: onClick: bind_service 
07-12 18:11:13.613 14981 14981 D ServiceBinderStatusTest: onBind: 1
07-12 18:11:13.618  3414  3414 D ServiceBinderStatusTest: onServiceConnected: 
07-12 18:11:16.191  3414  3414 D ServiceBinderStatusTest: onClick: unbindService
07-12 18:11:16.198 14981 14981 D ServiceBinderStatusTest: onUnbind: 1
07-12 18:11:19.122  3414  3414 D ServiceBinderStatusTest: onClick: stop_service
07-12 18:11:19.135 14981 14981 D ServiceBinderStatusTest: onDestroy: 

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    • bindService -> unbindService -> stopService

      07-12 18:12:14.835  3414  3414 D ServiceBinderStatusTest: onClick: bind_service 
07-12 18:12:14.853 14981 14981 D ServiceBinderStatusTest: onCreate: 
07-12 18:12:14.859 14981 14981 D ServiceBinderStatusTest: onBind: 1
07-12 18:12:14.864  3414  3414 D ServiceBinderStatusTest: onServiceConnected: 
07-12 18:12:15.792  3414  3414 D ServiceBinderStatusTest: onClick: stop_service
07-12 18:12:18.114  3414  3414 D ServiceBinderStatusTest: onClick: unbindService
07-12 18:12:18.119 14981 14981 D ServiceBinderStatusTest: onUnbind: 1
07-12 18:12:18.120 14981 14981 D ServiceBinderStatusTest: onDestroy: 

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    • startService -> unbindService -> stopService

      07-12 18:13:25.745  5715  5715 D ServiceBinderStatusTest: onClick: start_service
07-12 18:13:25.752 14981 14981 D ServiceBinderStatusTest: onStartCommand: 
07-12 18:13:25.752 14981 14981 D ServiceBinderStatusTest: onStart: 
07-12 18:13:26.822  5715  5715 D ServiceBinderStatusTest: onClick: unbindService
07-12 18:13:26.822  5715  5715 D AndroidRuntime: Shutting down VM
07-12 18:13:26.822  5715  5715 E AndroidRuntime: FATAL EXCEPTION: main
07-12 18:13:26.822  5715  5715 E AndroidRuntime: Process: jun.servicebinderstatustest, PID: 5715
07-12 18:13:26.822  5715  5715 E AndroidRuntime: java.lang.IllegalArgumentException: Service not registered: jun.servicebinderstatustest.MainActivity$1@722cdb7
07-12 18:13:26.822  5715  5715 E AndroidRuntime: 	at android.app.LoadedApk.forgetServiceDispatcher(LoadedApk.java:1757)
07-12 18:13:26.822  5715  5715 E AndroidRuntime: 	at android.app.ContextImpl.unbindService(ContextImpl.java:1874)
07-12 18:13:26.822  5715  5715 E AndroidRuntime: 	at android.content.ContextWrapper.unbindService(ContextWrapper.java:792)
07-12 18:13:26.822  5715  5715 E AndroidRuntime: 	at android.content.ContextWrapper.unbindService(ContextWrapper.java:792)
07-12 18:13:26.822  5715  5715 E AndroidRuntime: 	at jun.servicebinderstatustest.MainActivity.onClick(MainActivity.java:120)
07-12 18:13:26.822  5715  5715 E AndroidRuntime: 	at android.view.View.performClick(View.java:7448)
07-12 18:13:26.822  5715  5715 E AndroidRuntime: 	at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:1194)
07-12 18:13:26.822  5715  5715 E AndroidRuntime: 	at android.view.View.performClickInternal(View.java:7425)
07-12 18:13:26.822  5715  5715 E AndroidRuntime: 	at android.view.View.access$3600(View.java:810)
07-12 18:13:26.822  5715  5715 E AndroidRuntime: 	at android.view.View$PerformClick.run(View.java:28305)
07-12 18:13:26.822  5715  5715 E AndroidRuntime: 	at android.os.Handler.handleCallback(Handler.java:938)
07-12 18:13:26.822  5715  5715 E AndroidRuntime: 	at android.os.Handler.dispatchMessage(Handler.java:99)
07-12 18:13:26.822  5715  5715 E AndroidRuntime: 	at android.os.Looper.loop(Looper.java:223)
07-12 18:13:26.822  5715  5715 E AndroidRuntime: 	at android.app.ActivityThread.main(ActivityThread.java:7656)
07-12 18:13:26.822  5715  5715 E AndroidRuntime: 	at java.lang.reflect.Method.invoke(Native Method)
07-12 18:13:26.822  5715  5715 E AndroidRuntime: 	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
07-12 18:13:26.822  5715  5715 E AndroidRuntime: 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
07-12 18:13:26.837  5715  5715 I Process : Sending signal. PID: 5715 SIG: 9
07-12 18:13:26.854   271   271 I Zygote  : Process 5715 exited due to signal 9 (Killed)


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    问题4

    Exception ：“Service not registered”

    在调用unbindService时，如果connection没有注册或者已经被unbind了，系统会抛出异常java.lang.IllegalArgumentException: Service not registered

    问题5

    bindService返回true，Service也正常启动，但是没有onServiceConnect回调事件

    onBind返回结果为null时没有回调。

    在OnBind方法中需返回一个IBinder实例，不然onServiceConnected方法不会调用。

    问题6

    生命周期中startService 不会执行onBind,bindService 不会执行 onStartCommand和onStart

    • startService

      07-12 18:18:19.884  8816  8816 D ServiceBinderStatusTest: onClick: start_service
07-12 18:18:19.889 14981 14981 D ServiceBinderStatusTest: onCreate: 
07-12 18:18:19.890 14981 14981 D ServiceBinderStatusTest: onStartCommand: 
07-12 18:18:19.890 14981 14981 D ServiceBinderStatusTest: onStart: 

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    • bindService

      07-12 18:19:33.882  9760  9760 D ServiceBinderStatusTest: onClick: bind_service 
07-12 18:19:33.999  9903  9903 D ServiceBinderStatusTest: onCreate: 
07-12 18:19:33.999  9903  9903 D ServiceBinderStatusTest: onBind: 1
07-12 18:19:34.000  9760  9760 D ServiceBinderStatusTest: onServiceConnected: 

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    问题7

    bindService的返回值

    • bindService（）的返回值只是表明服务是否存在；

    • 真正能代表是否成功绑定服务的是触发onServiceConnected回调。

    bindService为异步操作，执行完bindService，并 不会马上回调onServiceConnected，当然也不会等待它；而是按照程序的顺序继续执行。这时由于服务还未成功获取到，调用服务中的方法就会出错。

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  • 原文地址：https://blog.csdn.net/Jun_P/article/details/126819312