Android Question Close B4XPage with Back Button

[Sergey_New]

Press the Up button to close the current page:

Sub Up_Click
    B4XPages.ShowPageAndRemovePreviousPages("MainPage")
End Sub

How to do this by pressing the back button of the device?

 

[Geezer]

'Return True to close, False to cancel
Private Sub B4XPage_CloseRequest As ResumableSub
    B4XPages.ShowPageAndRemovePreviousPages( "MainPage" )
    Return False
End Sub

 

[Sergey_New]

Geezer, error:

Spoiler: Error

Error occurred on line: 504 (B4XPagesManager)
java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.keywords.Common.CallSubDebug(Common.java:1050)
at b4a.example.b4xpagesmanager$ResumableSub_HandleCloseRequest.resume(b4xpagesmanager.java:811)
at b4a.example.b4xpagesmanager._handlecloserequest(b4xpagesmanager.java:781)
at b4a.example.b4xpagesmanager._activity_keypress(b4xpagesmanager.java:539)
at b4a.example.b4xpagesdelegator._activity_keypress(b4xpagesdelegator.java:63)
at b4a.example.main._activity_keypress(main.java:424)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.shell.Shell.runMethod(Shell.java:732)
at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:351)
at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:255)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:144)
at b4a.example.main$HandleKeyDelayed.runDirectly(main.java:231)
at b4a.example.main$HandleKeyDelayed.run(main.java:228)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.RuntimeException: java.lang.Exception: Sub B4XPage_CloseRequest was not found.
at anywheresoftware.b4a.debug.Debug.CallSub4(Debug.java:336)
at anywheresoftware.b4a.debug.Debug.CallSubNew(Debug.java:282)
... 22 more
Caused by: java.lang.Exception: Sub B4XPage_CloseRequest was not found.
at anywheresoftware.b4a.debug.Debug.CallSub4(Debug.java:326)
... 23 more
** Activity (main) Pause event (activity is not paused). **

 

[Sergey_New]

Removed spaces in (" MainPage ") and it works! Thanks!