This is for a shot I am writing for Edpresso|Educative.io called "How to Disable a button in Kivy?".

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How to Disable and Enable a button in Kivy

It is time to learn how to disable and enable a button in Kivy. This is necessary for many scenarios depending on the project you are working on or will be working on. If you wonder why, think about a user accidentally hitting the submit button on one of your apps, and there's nothing in the text input box. Disabling the submit button will come in handy because it will allow for those little moments that the user might accidentally hit the submit button when they are not ready to. Time to move on to learning how to code disabling a button!

First, we need to import the libraries and add the classes into our .py file, then load the .kv file into our .py file.

main.py

   import kivy
   from kivy.app import App
   from kivy.uix.widget import Widget
   from kivy.lang import Builder
   
   # load in the .kv file
   Builder.load_file('main.kv')
   
   class Shot(Wiget):
       pass
   
   class ShotApp(App):
       def build(self):
           return Shot()
           
   if __name__ == '__main__':
       ShotApp().run()

main.kv

<Shot>

Now, we have the function of our app. It is time to start adding the buttons in the design file (main.kv).

Let's add two buttons called "Button 1" and "Button 2", and disable "Button 2". To do this we will use a boolean statement from Kivy, disabled: True.

main.kv

<Shot>
    BoxLayout:
        orientation: "horizontal"
        size: root.width, root.height
    
        Button:
            text: "Button 1"
            size_hint: (1,1)
            disabled: False
            
        Button:
            text: "Button 2"
            size_hint: (1,1)
            disabled: True

Every button you add into Kivy will read as disabled: False automatically, so there is no need to add the disabled method on each button. In our case though we will add it to both of our buttons.

You now know how to disable a button. However, this does not do you justice unless you know how to enable "Button 2" and disable "Button 1". For the remainder of this shot we will go over how to do this. It is fairly simple.

We need to add a few more things to our buttons before we move back into the logic in the .py file. Each button needs to have an id: method and a on_press: method added.

main.kv

BoxLayout:
    orientation: "horizontal"
    size: root.width, root.height
    
    Button:
        # BELOW IS THE ID TAG
        id: but_one
        text: "Button 1"
        size_hint: (1,1)
        disabled: False
        # BELOW IS THE ON_PRESS TAG
        on_press: root.disabled_other()
        
    Button:
        # BELOW IS THE ID TAG
        id: but_two
        text: "Button 2"
        size_hint: (1,1)
        disabled: True
        # BELOW IS THE ON_PRESS TAG
        on_press: root.disable_other()

Finally, we can move back into our .py file! All we need to do is add our disable_other() method to our class Shot(). Then we add an if statement to disable_other() for our app to determine when our enabled button is pressed it will disable itself and enable the other button.

It should look something like this:

main.py

    import kivy
    from kivy.app import App
    from kivy.uix.widget import Widget
    from kivy.lang import Builder
    
    Builder.load_file('main.kv')
    
    class Shot(Widget):
    
        # Method to diable one button and activate the other
        def disable_other(self):
            if self.ids.but_two.disabled == False:
                self.ids.but_two.disabled = True
                self.ids.but_one.disabled = False
                print('Button 1 is now disabled. Button 2 is now enabled.')
            else:
                self.ids.but_one.disabled = True
                self.ids.but_two.disabled = False
                print('Button 1 is now enabled. Button 2 is now disabled.')
                
    class ShotApp(App):
        def build(self):
            return Shot()
            
    if __name__ == '__main__':
        ShotApp().run()

You now have the knowledge to disable and enable your buttons with Kivy on demand! Have fun coding!