ios - 是否有像数字键盘但允许负数的 UITextField 键盘类型？

Question

我在我的 UITextFields 上将 UIKeyboardType 设置为 UIKeyboardTypeNumberPad。但是，这只允许用户输入正整数。我需要用户能够输入负整数或正整数。是否有与 UIKeyboardTypeNumberPad 相同但还包含“-”(减号)符号的 UIKeyboardType，如果没有，我是否可以创建它？

谢谢。

Answer 1

这是一个 Swift 版本，它有一个 +/- 按钮，还有一个用于数字键盘的清除和完成按钮。

numeric keyboard screenshot

extension UITextField {

func addNumericAccessory(addPlusMinus: Bool) {
    let numberToolbar = UIToolbar()
    numberToolbar.barStyle = UIBarStyle.default

    var accessories : [UIBarButtonItem] = []

    if addPlusMinus {
        accessories.append(UIBarButtonItem(title: "+/-", style: UIBarButtonItem.Style.plain, target: self, action: #selector(plusMinusPressed)))
        accessories.append(UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: self, action: nil))   //add padding after
    }

    accessories.append(UIBarButtonItem(title: "Clear", style: UIBarButtonItem.Style.plain, target: self, action: #selector(numberPadClear)))
    accessories.append(UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: self, action: nil))   //add padding space
    accessories.append(UIBarButtonItem(title: "Done", style: UIBarButtonItem.Style.plain, target: self, action: #selector(numberPadDone)))

    numberToolbar.items = accessories
    numberToolbar.sizeToFit()

    inputAccessoryView = numberToolbar
}

@objc func numberPadDone() {
    self.resignFirstResponder()
}

@objc func numberPadClear() {
    self.text = ""
}

@objc func plusMinusPressed() {
    guard let currentText = self.text else {
        return
    }
    if currentText.hasPrefix("-") {
        let offsetIndex = currentText.index(currentText.startIndex, offsetBy: 1)
        let substring = currentText[offsetIndex...]  //remove first character
        self.text = String(substring)
    }
    else {
        self.text = "-" + currentText
    }
}

}