Created to help me, and maybe you, to navigate between Screens, load Screen Prefabs, update list of available Screens in Editor etc.

• in Unity go to Windows > Package Manager
• press + and select Add package from git URL...

https://github.com/gbviktor/ui-manager-for-unity.git

• Import from Samples a UILoadResources sample
• create a Folder UIScreens in Resources folder
• now you can create a ScriptableObject from Asset Menu in created UIScreens folder
  • Montana Games/DB/Screens List
    • this Scriptable Object looking for Prefabs inside this Folder (Root only) of type UIScreen and update list of available Screens
    • just put your Prefab in this Folder to make it visible for UI Manager
• after, you can create your first Screen inherited from/extends UIScreen class
  • see UITestScreen as a sample
• before UI Manager can work, initialize it with followed code (do it once, this script use static fields)

[SerializeField] ScreensList screensList;

void Awake(){
	//setup a Loader and
	new UI(new UILoaderResources(screensList))
}

• now, you can call UI.OpenScreen<UITestScreen>() or UI.OpenNested<UITestScreen>()
  • OpenNested open Screens with save previous Screen in Stack, to open it back again, if you close current. (also save history)

• UI.Open<UIYourScreenType>()
  • open new Screen and close automatically Previous (disabled/removed)
• UI.OpenNested<UIYourNextScreen>()
  • open new Screen, and save previous in History (stack) open it, if you close current
• UI.OpenAndCloseAllPrevious<UIMyScreen>()
  • close all Screen (clear history/stack), and open requested Screen
• UI.OnBackButtonPressed() - use it to handle users inputs,
  • this method will be close current Screen and open previous if History is not empty.
• UI.ForceCloseAll() - force close all opened Screens or saved in History (Stack)
  • use this, for Scenes transitions, to clear history of opened screens.
• UI.CloseCurrentFocusPrevious() - close current screen, focus previous
• UI.Get<UIMyScreen>() - instantiate a Screen, but not Open it (don't call OnOpen event)
  • you can manipulate or execute with this Screen before open
    • but i will be not recommend this method, smell like a bad practice
• UI.DestroyScreen<UIMyScreen>() - remove/destroy this screen from Scene
  • use it careful, only if you manually want close screen and can't use UI.CloseCurrentFocusPrevious()

• create a new Canvas in Scene
• add you script/component inherited from UIScreen to this Canvas
• rename it, i recommend to name it like UI(some your name)Screen
• save this Canvas as Prefab in root of folder where a ScriptableObject of type ScreensList already exist, or create it inside
  • this SO help you, it's make a updatable list of available Screens inside folder where SO persistent
• after this steps, you can call in your code UI.OpenNested<UISomeMyNewScreen>()
  • if you got error, check this step again.

• under development...