Android Kotlin-如何设置DialogInterface.OnClickListener的默认值作为函数参数

Question

这是我的函数声明：

fun MyDialog(ctx: Context, msg: String, yestext: String = "", OnYes: DialogInterface.OnClickListener): AlertDialog

如何设置"OnYes：DialogInterface.OnClickListener"的默认值？

我尝试过OnYes:DialogInterface.OnClickListener=null，但它不起作用。

Answer 1

@mangkool 提供的答案

OnYes：DialogInterface.OnClickListener？=空

Answer 2

val builder = AlertDialog.Builder(this@MainActivity)
// Set the alert dialog title
builder.setTitle("App background color")
// Display a message on alert dialog
builder.setMessage("Are you want to set the app background color to RED?")
// Set a positive button and its click listener on alert dialog
builder.setPositiveButton("YES"){dialog, which ->
// Do something when user press the positive button
Toast.makeText(applicationContext,"Ok, we change the app background.",Toast.LENGTH_SHORT).show()
// Change the app background color
root_layout.setBackgroundColor(Color.RED)
}

// Display a negative button on alert dialog
builder.setNegativeButton("No"){dialog,which ->
Toast.makeText(applicationContext,"You are not agree.",Toast.LENGTH_SHORT).show()
}

// Display a neutral button on alert dialog
builder.setNeutralButton("Cancel"){_,_ ->
Toast.makeText(applicationContext,"You cancelled the dialog.",Toast.LENGTH_SHORT).show()
}
// Finally, make the alert dialog using builder
val dialog: AlertDialog = builder.create()
// Display the alert dialog on app interface
dialog.show()