class BeautyDialog : DialogFragment() {

    private var iDialogTitle: IDialogTitle?     = null
    private var iDialogContent: IDialogContent? = null
    private var iDialogFooter: IDialogFooter?   = null

    // ...

    override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
        // ...
    }

    @BeautyDialogDSL class Builder {
        private var dialogTitle: IDialogTitle?      = null
        private var dialogContent: IDialogContent?  = null
        private var dialogFooter: IDialogFooter?    = null

        // ...

        /** 为对话框指定头部 */
        fun withTitle(iDialogTitle: IDialogTitle) {
            this.dialogTitle = iDialogTitle
        }

        /** 为对话框指定内容 */
        fun withContent(iDialogContent: IDialogContent) {
            this.dialogContent = iDialogContent
        }

        /** 为对话框指定底部 */
        fun withBottom(iDialogFooter: IDialogFooter) {
            this.dialogFooter = iDialogFooter
        }

        fun build(): BeautyDialog {
            val dialog = BeautyDialog()
            // ...
            return dialog
        }
    }
}

/** 提供了基于 kotlin DSL 风格的对话框构建器 */
inline fun createDialog(
    init: BeautyDialog.Builder.() -> Unit
): BeautyDialog = BeautyDialog.Builder().apply(init).build()

val theme = when(dialogStyle) {
    STYLE_WRAP      -> R.style.BeautyDialogWrap
    STYLE_HALF      -> R.style.BeautyDialogHalf
    STYLE_TWO_THIRD -> R.style.BeautyDialogTwoThird
    else            -> R.style.BeautyDialog
}
val dialog = if (bottomSheet) {
    BottomSheetDialog(requireContext(), theme)
} else {
    AlertDialog.Builder(requireContext(), theme).create()
}

val dialog = if (bottomSheet) {
    BottomSheetDialog(requireContext(), theme).apply {
        halfExpandedRatio?.let { this.behavior.halfExpandedRatio = it }
        isFitToContents  ?.let { this.behavior.isFitToContents   = it }
        peekHeight       ?.let { this.behavior.peekHeight        = it }
    }
} else {
    AlertDialog.Builder(requireContext(), theme).create()
}