Question

我想对textfield进行限制。示例：最大字符数应为6，字符只能为数字。但我无法将这两个控件放在一个函数中。

文本计数的第一个函数：

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2018-04-30T15:15:30.216789+00:00 heroku[router]: at=error code=H12 desc="Request timeout" method=GET path="/?url=https://google.com/" host=url2screenshot-imm.herokuapp.com request_id=a2d17f7a-4988-4414-864b-f916d26f05e6 fwd="186.247.177.201" dyno=web.1 connect=1ms service=30000ms status=503 bytes=0 protocol=https

2018-04-30T15:15:30.283300+00:00 heroku[router]: at=error code=H12 desc="Request timeout" method=GET path="/?url=https://reddit.com/" host=url2screenshot-imm.herokuapp.com request_id=73b70dad-851f-4e8b-a06b-4c647b7aa02f fwd="186.247.177.201" dyno=web.1 connect=0ms service=30000ms status=503 bytes=0 protocol=https

2018-04-30T15:15:30.283055+00:00 heroku[router]: at=error code=H12 desc="Request timeout" method=GET path="/?url=https://twitter.com/" host=url2screenshot-imm.herokuapp.com request_id=786dc9a0-4048-4fce-b9a5-96c2caf63c8d fwd="186.247.177.201" dyno=web.1 connect=3ms service=30001ms status=503 bytes=0 protocol=https

2018-04-30T15:15:30.254133+00:00 heroku[router]: at=error code=H12 desc="Request timeout" method=GET path="/?url=https://yahoo.com/" host=url2screenshot-imm.herokuapp.com request_id=f5dc9005-f655-4ef9-9172-893d105480e4 fwd="186.247.177.201" dyno=web.1 connect=15ms service=30000ms status=503 bytes=0 protocol=https

2018-04-30T15:15:30.358536+00:00 heroku[router]: at=error code=H12 desc="Request timeout" method=GET path="/?url=https://youtube.com/" host=url2screenshot-imm.herokuapp.com request_id=926f7516-f270-4de1-9aa4-f2a9d63b36bc fwd="186.247.177.201" dyno=web.1 connect=0ms service=30000ms status=503 bytes=0 protocol=https

文本类型的第二个函数：

func textFieldCharacterCountLimit(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    let maxLength = 6
    let currentString: NSString = txt_phone_no_verification_code.text! as NSString
    let newString: NSString =
        currentString.replacingCharacters(in: range, with: string) as NSString
    return newString.length <= maxLength
}

除此之外，它也会出错。而textFieldCharacterCountLimit函数不起作用。我想我得到一个错误，因为两个函数影响相同的textfield返回。感谢

Answer 1

仅允许将特定字符集输入到具有特定范围的给定文本字段

   func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        if string.count == 0 {
            return true
        }
        let currentText = textField.text ?? ""
        let prospectiveText = (currentText as NSString).replacingCharacters(in: range, with: string)

        return prospectiveText.containsOnlyCharactersIn(matchCharacters: "0123456789") &&
            prospectiveText.count <= 6

    }

带条件的字符串扩展

extension String {

    // Returns true if the string contains only characters found in matchCharacters.
    func containsOnlyCharactersIn(matchCharacters: String) -> Bool {

        let disallowedCharacterSet = NSCharacterSet(charactersIn: matchCharacters).inverted
        return self.rangeOfCharacter(from: disallowedCharacterSet as CharacterSet) == nil
    }
}

如何编写仅包含最大长度
的数字输入的iOS文本字段

http://www.globalnerdy.com/2015/04/27/how-to-program-an-ios-text-field-that-takes-only-numeric-input-or-specific-characters-with-a-maximum-length/

Answer 2

您不能仅仅组成委托方法名称。您需要实现正确的方法，并在一种方法中进行所有需要的检查。

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    let newString = (textField.text! as NSString).replacingCharacters(in: range, with: string)
    if newString.count > 6 {
        return false
    }

    return newString.rangeOfCharacter(from: CharacterSet.decimalDigits.inverted) == nil
}

为textfield swift 4设置字符数和字符类型限制

2 个答案: