java.lang.NullPointerException: Attempt to invoke interface method 'void android.app.DatePickerDialog$OnDateSetListener.onDateSet(android.widget.DatePicker, int, int, int)' on a null object reference
	at h4.x2$b.onClick(Unknown Source:20)
	at androidx.appcompat.app.AlertController$g.handleMessage(Unknown Source:37)
	at android.os.Handler.dispatchMessage(Handler.java:107)
	at android.os.Looper.loop(Looper.java:227)
	at android.app.ActivityThread.main(ActivityThread.java:7822)
	at java.lang.reflect.Method.invoke(Native Method)
	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1026)