NullPointerException: Attempt to invoke virtual method ... on a null object reference

[mate-from-mattr]

One of my colleagues reported this crash to me. Sometimes the app will open, and show the splash screen for a split second, and then crash. When this happens, he tries a few more times. After a few attempts, the app opens up fine and he can use it.

11-10 13:30:47.203 E/AndroidRuntime(23581): java.lang.NullPointerException: Attempt to invoke virtual method 'boolean com.ninty.system.setting.SystemSetting$g.a()' on a null object reference
11-10 13:30:47.203 E/AndroidRuntime(23581): 	at com.ninty.system.setting.SystemSetting.registerVolumeReceiver(Unknown Source:2)
11-10 13:30:47.203 E/AndroidRuntime(23581): 	at com.ninty.system.setting.SystemSetting.onHostResume(Unknown Source:0)
11-10 13:30:47.203 E/AndroidRuntime(23581): 	at com.facebook.react.bridge.ReactContext$1.run(Unknown Source:17)
11-10 13:30:47.203 E/AndroidRuntime(23581): 	at android.os.Handler.handleCallback(Handler.java:959)
11-10 13:30:47.203 E/AndroidRuntime(23581): 	at android.os.Handler.dispatchMessage(Handler.java:100)
11-10 13:30:47.203 E/AndroidRuntime(23581): 	at com.facebook.react.bridge.queue.MessageQueueThreadHandler.dispatchMessage(Unknown Source:5)
11-10 13:30:47.203 E/AndroidRuntime(23581): 	at android.os.Looper.loopOnce(Looper.java:257)
11-10 13:30:47.203 E/AndroidRuntime(23581): 	at android.os.Looper.loop(Looper.java:342)
11-10 13:30:47.203 E/AndroidRuntime(23581): 	at android.app.ActivityThread.main(ActivityThread.java:9638)
11-10 13:30:47.203 E/AndroidRuntime(23581): 	at java.lang.reflect.Method.invoke(Native Method)
11-10 13:30:47.203 E/AndroidRuntime(23581): 	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:619)
11-10 13:30:47.203 E/AndroidRuntime(23581): 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:929)

Looking at the source for registerVolumeReceiver, I think volumeBR may be null? Looking at stack trace, it looks like it's calling a method that returns bool. I'm not absolutely sure. If it is null, I wondered also if it might be a race condition, where volumeBR is set to null at one point, and instantiated at another. Not sure!

Is this a problem with the way i'm using the library, or with the library itself?

Using react-native: 0.79.5, but don't have many more details at this time. May be able to get you more if you need.

[Anand9893]

Yes, I am also facing this issue with my application. For me, it is crashing all the time. Using react-native: 0.81.4. Not sure if there is a fix for this?

[kevinscud]

I had this issue with my application, so I created a fix here: https://github.com/kevinscud/react-native-system-setting