斯威夫特 UITextView

Posted 2023-02-24

【中文标题】斯威夫特 UITextView

【英文标题】：Swift UITextView

【发布时间】：2014-12-03 15:15:47

【问题描述】：

我正在尝试创建一个 UiTextView，它只能输入 50 个字符，长度不应超过两行，当按下返回时关闭键盘。基于许多 stackover 尝试了各种方法，但似乎没有一个可以解决问题。不确定它必须如此难以做到。任何帮助将不胜感激

目前正在使用

    func textView(textView: UITextView!, shouldChangeTextInRange: NSRange, replacementText: NSString!)
if let range = text.rangeOfCharacterFromSet(NSCharacterSet.newlineCharacterSet()) 
        println("start index: \(range.startIndex), end index: \(range.endIndex)")
    
    else 
        println("no data")
    

【问题讨论】：

Limit number of characters in uitextview的可能重复

【参考方案1】：

我不确定您所说的“长度不应超过两行”是什么意思，但我可以向您展示如何实现该委托方法以将文本输入限制为 50 个或更少的字符。

func textView(textView: UITextView, shouldChangeTextInRange range: NSRange, replacementText text: String) -> Bool 
    // range contains the range of text that is currently selected, this will be overwritten after this method returned true. If length is 0 nothing will be overwritten
    // text contains the replacement text, might be the empty string "" which indicates deletion

    // current text content of textView must be converted from String to NSString 
    // because stringByReplacingCharactersInRange(...) is a method on NSString
    let currentText = textView.text as NSString

    // do the changes that would happen if this method would return true
    let proposedText = currentText.stringByReplacingCharactersInRange(range, withString: text)
    if countElements(proposedText) > 50 
        // text would be longer than 50 characters after the changes are applied
        // so ignore any input and don't change the content of the textView
        return false
    
    // go ahead and change text in the textView
    return true

内联 cmets 应该解释所有必要的内容。