Android app Crash when I click the Spinner with its spinnerMode "dialog" in Android 6 or 7

Question

The errors are follows:

java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Class android.view.View.getClass()' on a null object reference
        at com.android.internal.app.WindowDecorActionBar.getDecorToolbar(WindowDecorActionBar.java:246)
        at com.android.internal.app.WindowDecorActionBar.init(WindowDecorActionBar.java:198)
        at com.android.internal.app.WindowDecorActionBar.<init>(WindowDecorActionBar.java:180)
        at android.app.Dialog.show(Dialog.java:316)
        at androidx.appcompat.widget.AppCompatSpinner$DialogPopup.show(AppCompatSpinner.java:898)
        at androidx.appcompat.widget.AppCompatSpinner.showPopup(AppCompatSpinner.java:600)
        at androidx.appcompat.widget.AppCompatSpinner.performClick(AppCompatSpinner.java:444)
        at android.view.View$PerformClick.run(View.java:22433)
        at android.os.Handler.handleCallback(Handler.java:751)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        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)

I found it didn't crash in Android 10+,but the mode of the Spinner become "dropdown". It seems the dialog mode didn't work. I don't have any ideas for this problem.