EditText() 的奇怪问题 - Android Kotlin

Question

我遇到了这个奇怪的问题：

    // definition
    var myEditText: EditText? = null

    .
    .
    .

    // instantiation
    myEditText = EditText(this)
    myEditText?.setSingleLine(true)
    myEditText?.setTextColor(Color.YELLOW)
    myEditText?.setBackgroundColor(Color.RED)
    myEditText?.setPadding(10, 0, 10, 0)
    myEditText?.gravity = Gravity.CENTER_VERTICAL
    myEditText?.inputType = InputType.TYPE_TEXT_FLAG_CAP_CHARACTERS
    myEditText?.setOnFocusChangeListener { view, hasFocus -> ...

    rootView.addView(myEditText)

    .
    .
    .

    if (myEditText?.text == null || myEditText?.text.trim() == "") {

        println("it's blank!")   // doesn't execute

    } else {

        println(">>>" + myEditText?.text.trim() + "<<<")

    }

    // output: >>><<<

EditText() 控件已正确实例化并正确显示在屏幕上。我可以输入文本，它会 return 正确输入条目。

但是为什么不能识别文本框是空的？

Answer 1

myEditText?.text.toString()

你应该使用toString()

Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.

EditText() 的奇怪问题 - Android Kotlin

Strange Problem with EditText() - Android Kotlin

android

trim

android-edittext

kotlin