BetterDialog.kt

class BetterDialog<T> : DialogFragment() {
    companion object {
        val KEY_ARGS = "KEY_ARGS"
        val KEY_CALLED_FROM_FRAGMENT = "KEY_CALLED_FROM_FRAGMENT"
        val TAG = "DIALOG_TAG"
    }

    @Suppress("UNCHECKED_CAST")
    private val args: DialogBuilderImpl.DialogArgs<T> by lazy {
        checkNotNull(arguments?.getSerializable(KEY_ARGS) as DialogBuilderImpl.DialogArgs<T>) { "Args are null!" }
    }

    private val isCalledFromFragment by lazy {
        checkNotNull(arguments?.getBoolean(KEY_CALLED_FROM_FRAGMENT)) { "Args are null!" }
    }

    @Suppress("UNCHECKED_CAST")
    private fun getParent(): T {
        return if (isCalledFromFragment) {
            parentFragment as T
        } else {
            activity as T
        }
    }

    @NonNull
    @Suppress("UNCHECKED_CAST")
    override fun onCreateDialog(@Nullable savedInstanceState: Bundle?): Dialog {
        val context: Context =
            checkNotNull(activity) { "Unable to show dialog, activity is null!" }

        args.run {
            val b = AlertDialog.Builder(context)
            title?.let { b.setTitle(it) }
            message?.let { b.setMessage(it) }
            yesButtonAction?.let {
                b.setPositiveButton(yesButtonText) { _, _ ->
                    (it as DialogCallback<T>).invoke(
                        getParent()
                    )
                }
            }
            noButtonAction?.let {
                b.setNegativeButton(noButtonText) { _, _ ->
                    (it as DialogCallback<T>).invoke(
                        getParent()
                    )
                }
            }
            return b.create()
        }
    }
}