錯誤：java.lang.IllegalArgumentException: Receiver not registered

 Caused by: java.lang.IllegalArgumentException: Receiver not registered: com.multak.cookaraclient.MainActivi$NetState@3f3a124
 at android.app.LoadedApk.forgetReceiverDispatcher(LoadedApk.java:861)
 at android.app.ContextImpl.unregisterReceiver(ContextImpl.java:1352)
 at android.content.ContextWrapper.unregisterReceiver(ContextWrapper.java:576)
 at .MainActivity.onStop(MainActivity.java:493)
 at android.app.Instrumentation.callActivityOnStop(Instrumentation.java:1288)
 at android.app.Activity.performStop(Activity.java:6534)
 at android.app.ActivityThread.performStopActivityInner(ActivityThread.java:35
 at android.app.ActivityThread.handleStopActivity(ActivityThread.java:3588) 
 at android.app.ActivityThread.access$1200(ActivityThread.java:165) 
 at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1404) 
 at android.os.Handler.dispatchMessage(Handler.java:102) 
 at android.os.Looper.loop(Looper.java:150) 

修改：在OnCreate注冊時，就在 OnDeatory 反注冊。保證(register， unregister)成對出現