Android Question What is a "Weak Reference"?

[GuyBooth]

I am using a "pop-up" menu, using the InputMenu library over a CustomListView. Quite frequently - but not always - when I long-click on a menu selection the menu reacts visibly, but the code doesn't work. The app then crashes, and the logs show this message, with "weak reference" in the first line:

java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object java.lang.ref.WeakReference.get()' on a null object reference
    at anywheresoftware.b4a.Msgbox$DialogResponse.onClick(Msgbox.java:119)
    at com.android.internal.app.AlertController$AlertParams$3.onItemClick(AlertController.java:1149)
    at android.widget.AdapterView.performItemClick(AdapterView.java:339)
    at android.widget.AbsListView.performItemClick(AbsListView.java:1550)
    at android.widget.AbsListView$PerformClick.run(AbsListView.java:3721)
    at android.widget.AbsListView$3.run(AbsListView.java:5660)
    at android.os.Handler.handleCallback(Handler.java:739)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Looper.loop(Looper.java:145)
    at android.app.ActivityThread.main(ActivityThread.java:6873)
    at java.lang.reflect.Method.invoke(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:372)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1404)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)

None of the lines contain any recognisable reference to my own code.
This has been bugging me for (literally) years, and maybe it's time I found out what the problem is. Does anyone have similar experience, or better yet, know what the solution is?

 

[KMatle]

https://en.wikipedia.org/wiki/Weak_reference

Hm. Seems that an object has been removed (by Android) (by code) for some reason. Maybe it's a following error?

 

[Erel]

It looks like a problem in the library. There is another similar report in the library thread: https://www.b4x.com/android/forum/threads/inputmenu-library.29712/#post-215446

You will probably get better results with this library: https://www.b4x.com/android/forum/t...r-utilities-for-the-standard-actionbar.36898/ (there are other relevant libraries as well).