以下内容适用于

UITextField

UITextView

有用的信息

文本字段文本的最开始：

let startPosition: UITextPosition = textField.beginningOfdocument

文本字段文本的末尾：

let endPosition: UITextPosition = textField.endOfdocument

当前选择的范围：

let selectedRange: UITextRange? = textField.selectedTextRange

获取光标位置

if let selectedRange = textField.selectedTextRange {    let cursorPosition = textField.offset(from: textField.beginningOfdocument, to: selectedRange.start)    print("(cursorPosition)")}

设定光标位置

为了设置位置，所有这些方法实际上都是使用相同的开始值和结束值来设置范围。

从头开始

let newPosition = textField.beginningOfdocumenttextField.selectedTextRange = textField.textRange(from: newPosition, to: newPosition)

到最后

let newPosition = textField.endOfdocumenttextField.selectedTextRange = textField.textRange(from: newPosition, to: newPosition)

在当前光标位置左侧的一个位置

// only if there is a currently selected rangeif let selectedRange = textField.selectedTextRange {    // and only if the new position is valid    if let newPosition = textField.position(from: selectedRange.start, offset: -1) {        // set the new position        textField.selectedTextRange = textField.textRange(from: newPosition, to: newPosition)    }}

到任意位置

从头开始，向右移动5个字符。

let arbitraryValue: Int = 5if let newPosition = textField.position(from: textField.beginningOfdocument, offset: arbitraryValue) {    textField.selectedTextRange = textField.textRange(from: newPosition, to: newPosition)}

有关

选择所有文字

textField.selectedTextRange = textField.textRange(from: textField.beginningOfdocument, to: textField.endOfdocument)

选择文字范围

// Range: 3 to 7let startPosition = textField.position(from: textField.beginningOfdocument, offset: 3)let endPosition = textField.position(from: textField.beginningOfdocument, offset: 7)if startPosition != nil && endPosition != nil {    textField.selectedTextRange = textField.textRange(from: startPosition!, to: endPosition!)}

在当前光标位置插入文本

textField.insertText("Hello")

笔记

• 使用

  textField.becomeFirstResponder()

  给予重点的文本字段，使键盘出现。