Allow to use enum class for SwapperViews

[levibostian]

According to the README doc, this project suggests that you use an enum to represent the Views to swap between. This is great, but it requires more work: swapTo(SwapperView.ViewName.name). It would be great if all you needed to do was swapTo(.ViewName) when you need to swap.

This can be done with a generic on SwapperView.

[levibostian]

The hard part is that I cannot use generics with the constructor if I want to use SwapperView in XML.

[levibostian]

// delete `SwapperViewId` typealias
typealias SwapperViewSwapAnimator = (oldView: View, newView: View, duration: Long, onComplete: () -> Unit) -> Unit

class SwapperView<SwapperViewId: Any>: FrameLayout {

Then the example app...

class MainActivity : AppCompatActivity() {

    enum class SwapperViews {
        FIRST_VIEW,
        SECOND_VIEW
    }

    @Suppress("UNCHECKED_CAST")
    private val swapperView: SwapperView<SwapperViews>
        get() = this.swapper_view as SwapperView<SwapperViews>

    private fun setupViews() {
        swapperView.apply {
            viewMap = mapOf(
                Pair(SwapperViews.FIRST_VIEW, first_view),
                Pair(SwapperViews.SECOND_VIEW, second_view)
            )
            swapTo(SwapperViews.FIRST_VIEW) {
                first_view_imageview.load("https://raw.githubusercontent.com/levibostian/Swapper-iOS/d494bc41894b5e5bc7eeacc162a96ddadca024cc/Example/Swapper/Images.xcassets/little_hill.imageset/little_hill.jpg")
            }
        }

        second_view_swap_button.setOnClickListener {
            swapperView.swapTo(SwapperViews.FIRST_VIEW) 
        }
    }
}

Pros:

• We accomplished it! Allowing any type.

Cons:

• You have to add this hacky code:

    @Suppress("UNCHECKED_CAST")
    private val swapperView: SwapperView<SwapperViews>
        get() = this.swapper_view as SwapperView<SwapperViews>

I am thinking there is a better way.

[levibostian]

My idea right now is that you add in XML SwapperViewContainer

In your Activity, you call:

swapper_view_container.init(...)

Where you pass in your ViewMap to init and the first view to swap to. It will (1) return back a strongly typed instance of SwapperView and will also populate the container with the swapperview instance.

This would allow you to have a strongly typed constructor.

[levibostian]

Ended up with a better idea overall. Remove the need for enum, period! No more viewMap = ...!