Kivy Popup Widget -already has a parent widget error

[bhavar kumavat]

Here is the Code I am on.

Popup works for the first time when the Button '1' is clicked but If I click again on the button I get an error

'kivy.uix.widget.WidgetException: Cannot add <__main__.ButtonOne object at 0x03B04AE8>, it already has a parent <kivy.uix.boxlayout.BoxLayout object at 0x068CD228>'

I don't know why is this happening anyone could explain me this,It would be appreciable.

from kivy.app import App
from kivy.uix.button import Button
from kivy.uix.gridlayout import GridLayout
from kivy.lang import Builder
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.scrollview import ScrollView
from kivy.uix.popup import Popup
Builder.load_string('''
<MyApp>:
    BoxLayout:
        orientation:'horizontal'
        GridLayout:
            cols:1
            padding:20
            spacing:20
            TextInput:
                id:search_key
                size_hint:1,None
                height:50
                multiline:False
                spacing:20
                on_text_validate:root.d()
            Button:

        BoxLayout:
            orientation:'vertical'
            ScrollView:
                size_hint:1,1
                GridLayout:
                    size_hint:1,None
                    height:self.minimum_height
                    cols:1
                    BoxLayout:
                        size_hint:1,None
                        height:500
                        orientation:'vertical'
                        Button:
                            size_hint:1,.7

			    text:'1'
                            on_press:app.get_image()
                        GridLayout:
                            size_hint:1,.3
                            cols:3
                            Button:
                            Button:
                            Button:
                    Button:
                        size_hint:1,None
                        height:500

                    Button:
                        size_hint:1,None
                        height:500
''')

class ButtonOne(Button):
    pass

class CustomPopup(Popup):
    from kivy.uix.button import Button
    b=ButtonOne()
    def __init__(self,**kwargs):
        super(CustomPopup,self).__init__(**kwargs)
        self.size_hint=[.5,.5]
        self.auto_dismiss=False
        self.title='That\'s the title'
        self.b.text="Just a button"
        self.b.bind(on_release=self.dism)
        self.content=self.b
    def dism(self,*args):
        self.dismiss()

class MyApp(BoxLayout):
    def d(self):
        print 'lost focus'
    pass

class Main(App):
    def build(self):
        return MyApp()

    def get_image(self):
        c=CustomPopup()
        c.open()

Main().run()

[OPQ]

Indedd, as the message says: the first time you click, you attached the class-linked ButtonOne to a first popup. 

The second time you click;, you attached the SAME buttonOne to a new popup.

A widget child can not be moved around. It has to be detached from its parent, before being added to a new parent.

As such, you can either:

- create a new buttonOne each time you click, which is probably the desired behavior (replace self.content = self.b by self.content = self.b = ButtonOne())

- or, if you really need to keep the same button around, you'll have to untach it from its parent: priori to self.content = self.b, add a new line with  self.b.parent.remove_widget(self.b)

--OPQ