ScreenManager | Flexible way to manage screens with transitions for Unity | Game Engine library

Since Main is just a class and not an instance, and since in python it is possible to have multiple instances, what you really need is a way to get the Main instance created by kivy. I have not tested but I think this will work:

If you define your application root in the kv file, then the ids are available everywhere in that root rule. And then you can define an ObjectProperty in the ExercisePage that refers to the TextInput text. Here is what such a kv file could look like:

To change the label with the id address in the CreateServer screen simply go the CreateServer class and do the following changes.

Look at the following line in your code for the MDRaisedButton on_release event handler.

I had the same problem and found the problem and a workaround, not the solution though:

The problem lies within the Drawable Object created in the file plyer/platforms/android/notification.py. If you print(dir(Drawable)), you will find no attibute icon (as the error message stated). I don't know why the icon attribute is missing, but you will find there is a presplash attribute instead (which is also a .png file and thus replaceable).

By changing line 100 in the notification.py from app_icon = Drawable.icon to app_icon = Drawable.presplash, I could dodge the error and my app worked perfectly well. You need to change the line in the correct file though, which is located at ProjectName/.buildozer/android/platform/build-armeabi-v7a/build/python-installs/projectname/plyer/platforms/android.

Your kv seems to be overly complicated. In your First Screen you have a MDBoxLayout containing a MDScreen, containing a MDBottomNavigation, containing a MDBottomNavigationItem, containing a MDScreen, containing a MDBoxLayout, containing a MDGridLayout. Unless there are reasons that are not apparent from your code, I would suggest simplifying that kv.

And when you use ScrollView, you need its child to use adaptive_height: True (for vertical scrolling). And when using adaptive_height: True, the children of that widget must have explicit height values (size_hint_y set to None for vertical scrolling).

So here is a simplified version of your kv with a ScrollView and explicit height values where needed:

You can use Animation to do that by animating the angle. Something like:

In your add() method, the code:

You are doing some strange things in that code. First, using size_hint values greater than 1 (as you do for your ScrollView) sets the size of the ScrollView greater than its container. That means that you will not be able to see the entire ScrollView.

Similarly, you are setting pos_hint values to numbers less than 0. That positions the Buttons outside of the FloatLayout, so they will not be visible.

I suggest eliminating the line: