Question

我们如何用明确读取的值替换下面突出显示的值？

String msg ="BGM+EFD:20:109:GBP+aa:bb:cc+5+dd'CST++KindOfDeclaration+0'";
String bgm=msg.split("\\'") [0];

String tempMessage=bgm;

String messageFunction="56";

System.out.println(bgm);

if(StringUtils.isNotEmpty(messageFunction)){

    bgm=bgm.replace(bgm.split("\\+")[3],messageFunction);
}
else{
    bgm=bgm.replace(bgm.split("\\+")[3],"9");
}
msg=msg.replace(tempMessage, bgm);

即我需要从服务器读取值。它正确读取它，但它也取代了之前的值109.

例如，如果它正在读取的值是56，它将109替换为1056，这是我不需要的。我已经给出了如下代码

BGM+EFD:20:109:GBP+aa:bb:cc+56+dd'CST++KindOfDeclaration+0'";

必需的输出是

BGM+EFD:20:1056:GBP+aa:bb:cc+56+dd'CST++KindOfDeclaration+0'";

但我得到输出为

   @IBOutlet weak var bottomLayoutConstraint: NSLayoutConstraint!


    override func viewDidLoad() {
        super.viewDidLoad()

        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShowNotification(notification:)), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHideNotification(notification:)), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}


    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)

        // remove the observers so the code won't be called all the time
        NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillShow, object: nil)
        NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillHide, object: nil)
    }

    func keyboardWillShowNotification(notification: NSNotification) {
        updateBottomLayoutConstraintWithNotification(notification:notification)
    }

    func keyboardWillHideNotification(notification: NSNotification) {
        updateBottomLayoutConstraintWithNotification(notification:notification)
    }


    func updateBottomLayoutConstraintWithNotification(notification: NSNotification) {
        let userInfo = notification.userInfo!

        // get data from the userInfo
        let animationDuration = (userInfo[UIKeyboardAnimationDurationUserInfoKey] as! NSNumber).doubleValue
        let keyboardEndFrame = (userInfo[UIKeyboardFrameEndUserInfoKey] as! NSValue).cgRectValue
        let convertedKeyboardEndFrame = view.convert(keyboardEndFrame, from: view.window)
        let rawAnimationCurve = (notification.userInfo![UIKeyboardAnimationCurveUserInfoKey] as! NSNumber).uint32Value << 16
        let animationCurve = UIViewAnimationOptions(rawValue: UInt(rawAnimationCurve))

        bottomLayoutConstraint.constant = (view.bounds).maxY - (convertedKeyboardEndFrame).minY

        // animate the changes
        UIView.animate(withDuration: animationDuration, delay: 0.0, options: [.beginFromCurrentState, animationCurve], animations: {
            self.view.layoutIfNeeded()
        }, completion: nil)
    }

Answer 1

由于您的实际代码正在运行（我得到的输出不是您发布的错误的代码），这里是另一个使用正则表达式的解决方案：

这是一个简单的正则表达式，可以进行几乎相同的转换

msg = msg.replaceAll(
     "(.*\\+)(\\d+)(\\+.*'.*)", 
     "$1"
          + (StringUtils.isNotEmpty(messageFunction) ? messageFunction : "9" ) 
          + "$3"
)

这个正则表达式"(.*\\+)(\\d+)(\\+.*'.*)"只是让我在特定组中的'之前得到“+ +”之间的最后一个值。我想这可以改进。但结果是正确的。

group 1 : (.*\\+)
group 2 : (\\d+) the value you seek
group 3 : (\\+.*'.*)

我不是正则表达式的高手，所以它可能不是100％安全但是仍然可以改进。

需要使用明确读取的值替换字符串中的值

1 个答案: