Kotlin 接口回调示例

1. 只有一个方法时：

//接口定义：
private var onDeleteListener: ((String) -> Unit)? = null

    fun setOnDeleteListener(onDeleteListener: ((String) -> Unit)) {
        this.onDeleteListener = onDeleteListener
    }
    
// 使用
onDeleteListener?.invoke("delete")


//外部使用：
deleteDialog.setOnDeleteListener {
               Log.e("1111", "setOnDeleteListener：$it")
            }

2. 多于一个方法时：

==================================================
//仿java写法
interface DialogListener {
        fun dismiss()
        fun confirm()
    }

private var dialogListener : DialogListener ? = null

    fun setDialogListener(dialogListener: DialogListener){
        this.dialogListener = dialogListener 
    }    
//使用
dialogListener ?.confirm()
dialogListener ?.dismiss()

//外部调用
 dialog.setDialogListener(object : UnplacedDialog.DialogListener {
            override fun dismiss() {
            }

            override fun confirm() {
            }

        })
==================================================

//Kotlin写法（DSL）
inner class ListenerBuilder {
        internal var dismissAction: (() -> Unit)? = null
        internal var confirmAction: (() -> Unit)? = null

        fun dismiss(action: () -> Unit) {
            dismissAction = action
        }

        fun confirm(action: () -> Unit) {
            confirmAction = action
        }
    }
    
private var mListener: ListenerBuilder? = null

    fun addUDialogListener(listenerBuilder: ListenerBuilder.() -> Unit) {
        mListener = ListenerBuilder().also(listenerBuilder)
    }

//使用
mListener?.confirmAction?.invoke()
mListener?.dismissAction?.invoke()

//外部调用
dialog.addDialogListener {
            dismiss {
              
            }
            confirm {
            
        }
}

本文地址：https://blog.csdn.net/ssq236811/article/details/108724138