how to clear buttons created in a loop from a boxlayout

Question

i have a folderscreen that displays buttons from a loop, the buttons have title of the files saved, when i click the buttons, it opens a new page that shows the content of the file, but when i go back to the folder screen, 2 sets of the button in the loop are added to the existing buttons. what i want is everytime i leave the folderscreen, i want the buttons cleared, so that when i go back, it will run the loop code again and shows only the buttons from the loop without repetition. or may be there is a way i can stop the loop code from running if the boxlayout that house the buttons is not empty. here is my code:

    def on_enter(self, *args):
    objf = mm.Storenote()
    objf.tif(mm.DB.hod)
    for i in range(len(mm.Storenote.ht)):
        self.b = Button(text= (mm.Storenote.ht[i]), font_size = "25sp")
        #self.b.background_normal = ""
        self.b.background_color = 0,0,1,1
        self.b.ids =  {"id":mm.Storenote.nid[i]}
        self.b.size_hint=(1, None)
        self.b.size = (dp(370), dp(50))
        self.b.bind(on_press=self.build_clickk(self.b))
        self.ids.lpl.add_widget(self.b)

        #self.ids.lpl.add_widget(self.l[i])

def build_clickk(self, b):
    def clickk(*args):
        ci = b.ids.id
        print(ci)
        objff = mm.Show()
        objff.getter(ci)
        self.manager.current = "Readpage"
    return clickk
def on_leave(self, *args):
    self.ids.lpl.remove_widget(self.b)

the def on_leave function only remove one of the buttons and add 2 new sets of the button each time i go back to the folderscreen

Answer 1

You can use self.ids.lpl.clear_widgets() right before your for-loop. This way you ensure that the layout is empty before adding new widgets.

If you add many widgets, try using def on_pre_enter(). kivy will render the widgets before entering the screen and this may prevent "flickering" when building all widgets.