FiskDialog.kt

import android.app.Activity
import android.app.Dialog
import android.content.DialogInterface
import android.graphics.Color
import android.graphics.Point
import android.graphics.drawable.ColorDrawable
import android.graphics.drawable.GradientDrawable
import android.os.Build
import android.support.design.widget.BottomSheetBehavior
import android.support.design.widget.CoordinatorLayout
import android.util.DisplayMetrics
import android.view.Gravity
import android.view.View
import android.view.ViewGroup
import android.view.WindowManager

class FiskDialog(context: Activity, layout: Int, theme: Int) {

    val dialog: Dialog
    val contentView: View
    private var cancelable = true

    val coordinatorLayout: CoordinatorLayout

    init {

        dialog = Dialog(context, theme)

        val window = dialog.window

        if (window != null) {
            window.setDimAmount(0f)
            window.setBackgroundDrawable(ColorDrawable(Color.TRANSPARENT))
            window.setLayout(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT)
        }

        contentView = context.layoutInflater.inflate(layout, null)

        //Curved top corners:
        val curvedBackground = GradientDrawable()
        curvedBackground.setColor(Color.WHITE)

        val cornerRadius = 8 * (context.resources.displayMetrics.densityDpi.toFloat() / DisplayMetrics.DENSITY_DEFAULT)

        curvedBackground.cornerRadii = floatArrayOf(cornerRadius, cornerRadius, cornerRadius, cornerRadius, 0f, 0f, 0f, 0f)
        contentView.background = curvedBackground

        //Full screen coordinator to hold the bottomsheet
        coordinatorLayout = CoordinatorLayout(context)

        val layoutParams = WindowManager.LayoutParams(WindowManager.LayoutParams.MATCH_PARENT, WindowManager.LayoutParams.MATCH_PARENT)
        layoutParams.gravity = Gravity.CENTER
        coordinatorLayout.layoutParams = layoutParams
        coordinatorLayout.setBackgroundColor(Color.parseColor("#00000000"))

        val bottomSheetBehavior = BottomSheetBehavior<View>()
        bottomSheetBehavior.skipCollapsed = true
        bottomSheetBehavior.isHideable = true
        bottomSheetBehavior.state = BottomSheetBehavior.STATE_HIDDEN

        val params = CoordinatorLayout.LayoutParams(CoordinatorLayout.LayoutParams.MATCH_PARENT, CoordinatorLayout.LayoutParams.WRAP_CONTENT)
        params.behavior = bottomSheetBehavior

        contentView.layoutParams = params

        coordinatorLayout.addView(contentView)

        //Any click on the dimmed coordinator in the background should dismiss the dialog (unless setCanceleable(false); has been called):
        coordinatorLayout.setOnClickListener { _view -> if (cancelable) BottomSheetBehavior.from(contentView).state = BottomSheetBehavior.STATE_HIDDEN }

        bottomSheetBehavior.setBottomSheetCallback(object : BottomSheetBehavior.BottomSheetCallback() {

            override fun onStateChanged(bottomSheet: View, newState: Int) {
                when (newState) {
                    BottomSheetBehavior.STATE_HIDDEN -> {
                        dialog.dismiss()
                        //todo - create dismiss listener interface
                    }
                }
            }

            //slideOffset is float in range 0 to 1 - remapped to 0 to 153 (0x99000000)
            override fun onSlide(bottomSheet: View, slideOffset: Float) {
                val alpha = map(slideOffset, 0f, 1f, 0f, 153f).toInt()
                val overlayColor = Color.argb(alpha, Color.red(Color.BLACK), Color.green(Color.BLACK), Color.blue(Color.BLACK))

                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP && window != null) {
                    window.statusBarColor = overlayColor
                }

                coordinatorLayout.setBackgroundColor(overlayColor)
            }
        })


        dialog.setContentView(coordinatorLayout)

        //Without this the bottom sheet doesn't animate, despite the default state being hidden
        BottomSheetBehavior.from(contentView).state = BottomSheetBehavior.STATE_HIDDEN

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) dialog.create()
    }

    fun show() {
        dialog.show()
        contentView.post { BottomSheetBehavior.from(contentView).setState(BottomSheetBehavior.STATE_EXPANDED) }
    }

    fun dismiss() {
        BottomSheetBehavior.from(contentView).state = BottomSheetBehavior.STATE_HIDDEN
    }

    fun setOnShowListener(onShowListener: DialogInterface.OnShowListener) {
        dialog.setOnShowListener(onShowListener)
    }

    fun setCancelable(cancelable: Boolean) {
        this.cancelable = cancelable
        dialog.setCancelable(cancelable)
    }

    private fun map(value: Float, start1: Float, stop1: Float, start2: Float, stop2: Float): Float {
        return start2 + (stop2 - start2) * ((value - start1) / (stop1 - start1))
    }

    fun setMaxWidth(dp: Float) {
        val maxWidth = Math.round(contentView.context.resources.displayMetrics.density * dp)

        val display = dialog.window!!.windowManager.defaultDisplay
        val size = Point()
        display.getSize(size)

        if (size.x > maxWidth) {
            contentView.layoutParams.width = maxWidth
            (contentView.layoutParams as CoordinatorLayout.LayoutParams).gravity = Gravity.CENTER_HORIZONTAL
        }
    }

    fun setMaxWidth(dimenRes: Int) {
        val dp = contentView.context.resources.getDimension(dimenRes)
        setMaxWidth(dp)
    }
}