Question

我有四个textField用于OTP，并且还在ViewDidLoad（）方法中将委托设置为我的viewcontroller

我还实现了委托方法：

    func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
            if string.characters.count > 1 {
                return false
            } else {
                var tag = textField.tag
                if string.characters.count == 0 {
                    tag -= 1
                } else {
                    tag += 1
                }
                textField.text = string
                // Try to find next responder
                let nextResponder = textField.superview?.viewWithTag(tag) as UIResponder!
                nextResponder?.becomeFirstResponder()
            }
            return false
        }



func textFieldShouldReturn(textField: UITextField) -> Bool {
        print("BACKSPACE PRESSED")
        return true
    }

但是当字段为空时，这两种方法都不会调用，实际上我想要明文。任何想法如何检测＆＃34;退格＆＃34;在textfield为空时按下

Answer 1

有检测退格的代码

Answer 2

直接识别退格是不正确的逻辑。根据您的要求，您的文本字段变为空白，然后您希望以前的文本字段成为第一响应者，然后您需要像这样编写代码

func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {

    var txtAfterUpdate:NSString = textField.text! as NSString
    txtAfterUpdate = txtAfterUpdate.replacingCharacters(in: range, with: string) as NSString
    let updatedString = txtAfterUpdate as String

    if updatedString.characters.count == 0 {
        var tag = textField.tag
        tag -= 1
        let nextResponder = textField.superview?.viewWithTag(tag) as UIResponder!
        nextResponder?.becomeFirstResponder()

        return true
    } else{

        // rest of your functionality
    }

    return true
}

我希望它会对你有所帮助。

Answer 3

我通过覆盖UITextField的Follow Method来获得解决方案。

class MYTextField: UITextField {
    override func deleteBackward() {
        super.deleteBackward()
        delegate?.textFieldShouldReturn!(self)
        print("_____________BACKSPACE_PRESSED_____________")
    }
}

退格按不调用uitextfield的方法

3 个答案: