Find a crash

[LvZW1895]

APK Version : 2.0.20
AndroidOS Version: 7.1.2
Description information：
This crash happened by accident when I was testing in different devices. I tried to reproduce them and found that they can't be reproduced, but they are real. I hope they can help you to debug.

crash:
CRASH: io.pslab (pid 15648) (dump time: 2021-03-22 15:05:08
Version: 2.0.20Version:
Long Msg: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.view.View.setVisibility(int)' on a null object reference
at io.pslab.fragment.HomeFragment$1$1.onPageFinished(HomeFragment.java:125)
at u44.b(chromium-Monochrome.aab-stable-438909023:2)
at Ct.handleMessage(chromium-Monochrome.aab-stable-438909023:65)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6121)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:889)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:779)
crashend

[Abhinavtdk]

I'll try working on this

[faisalkhandholpur]

I can handle this issue

[kartikeysaran]

I am not able to reproduce this as i can see it can be either due to the visibility of the webview or the visibility of progress bar but both are initialized if you are able to reproduce this please ping me. Thanks !

[marcnause]

I managed to trigger a crash in the same class:

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.webkit.WebView.loadUrl(java.lang.String)' on a null object reference
   at io.pslab.fragment.HomeFragment$1.onClick(HomeFragment.java:111)
   at android.view.View.performClick(View.java:7259)
   at android.view.View.performClickInternal(View.java:7236)
   at android.view.View.access$3600(View.java:801)
   at android.view.View$PerformClick.run(View.java:27900)
   at android.os.Handler.handleCallback(Handler.java:883)
   at android.os.Handler.dispatchMessage(Handler.java:100)
   at android.os.Looper.loop(Looper.java:214)
   at android.app.ActivityThread.main(ActivityThread.java:7559)
   at java.lang.reflect.Method.invoke(Native Method)
   at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:935)

The crash does not happen in exactly the same location as the crash reported by @LvZW1895, but it happens just a few lines away. webviewshould also be not null here, but under certain conditions it is.

I was able to trigger the crash on my tablet (Lenovo Yoga Smart Tab, Android 10):

1. open app
2. tap "connect device' in the menu on the left
3. hover one finger over 'connect device'
4. hover another finger over 'What is PSLab Device'
5. tap with both fingers without changing the positions of the fingers on the screen rapidly and repeatedly

I propose adding null-checks in the methods onClick, onPageStarted and onPageFinished.

If nobody else wants to work on this I can fix the issue and create a pull request.