Modal support (dialogs)

[adam-arold]

Currently we use ComponentsLayerable:

class ComponentsLayerable(
        private val layerable: Layerable,
        private val components: DefaultContainer)
    : Layerable by layerable {

    override val layers: List<Layer>
        get() = components.toFlattenedLayers().plus(layerable.layers)
}

which composes a simple Layerable and a Container to manage both Components and simple Layers.

This should be improved by having a stack of Layerables:

• At the bottom there should be Components
• Above Components should be ModalComponents which have a size of the screen so the user can't interact with ordinary Components below a modal.
• At the top there are the "ordinary" Layers.

Things to do:

• Add addModal next to addComponent to ComponentContainer.
• Implement the layers stack in CompoentContainer instead of what we have now in TileGridScreen
• Factor out focus handling from DefaultComponentContainer into its own class

[coldwarrl]

Possible Feature List:

• obviously the possibility to position the modal dialog (and some defaults, like CENTER)
• title for dialog
• default submit button row (like Ok, Yes/No/Cancel etc.)
• the possibility to define a custom submit button row
• support for hotkeys (but I guess this should be more of a general feature ...shall we create a separate issue for that -> binding hotkeys to buttons and other UI elements ?)
• stacking of model dialogs (although from an ux perspective this is often an anti-pattern but there might be some usecases where stacking is helpful)

[adam-arold]

Good ideas! I think the dialog should work like a Panel (it can have shadow and a box around it with a title if using the latter option), but with the additional feature of having a button bar at the bottom (can be customized) and it blocks interaction with other components on the screen.

So the things you suggested are fine for a basic implementation but I think that stacking should be an enhancement later (if feasible). I was thinking about how the implementation should look like. Since a dialog should handle its own focus I think that behind the scenes a dialog should be a Screen with transparent background (because it has its own focus handling).

[coldwarrl]

That sounds good :) Yes, the stacking of dialogs is secondary...