UITextView .isEmpty 无法处理键盘发送 Swift

Question

有一个 UITextView 通过键盘上的 "Send" 按钮提交字符输入。我已经尝试了下面的所有这些，但它仍然没有字符地通过了。

func textView(_ textView: UITextView, shouldChangeTextIn  range: NSRange, replacementText text: String) -> Bool {
    if (text == "\n") {

        if(textView.text != "" || !textView.text.isEmpty){

          print("still printing")
         //**I dont want it to make it here but it does with no characters in textView after clicking send on keyBoard
        //It still makes it here when send button is pressed and textView is null.
            return false
        }

    }
    return true
}

这些我都试过了...

if(textView.text != "" || !textView.text.isEmpty || textView.text == nil)


if textView!.text.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines).isEmpty {
    [...]
}

if (self.textView.text.characters.count > 0) { }

1.) if (text == "\n") 表示 "Send" 按钮已被按下

2.) if(textView.text != "") 检查 textView 是否为 null

textView 为空，但仍然通过我在上面尝试过的 if 语句。

Answer 1

要获得新的文本长度，您需要使用如下范围和文本参数值：

func textView(_ textView: UITextView, shouldChangeTextIn  range: NSRange, replacementText text: String) -> Bool {
    let insertedText = text.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines)
    if insertedText.count == 1 {
        textView.text = insertedText
    }

    return false
}

Details: The shouldChangeTextIn is triggered before the text change on the UITextView. That makes sense because the decision for applying the change is taken in this function shouldChangeTextIn?.

UITextView .isEmpty 无法处理键盘发送 Swift

UITextView .isEmpty not working on keyboard send Swift

ios

swift

uitextview