建议在JavaFX文本字段中限制输入的方法 [英] Recommended way to restrict input in JavaFX textfield

问题描述

似乎问题是这个。但我的问题是我已经通过两种方式在JavaFX中开发了一个整数文本字段。代码如下：

It may seem the question is the duplicate of this. But my question is i have developed a integer textfield in JavaFX by two ways. The code is given below

public class FXNDigitsField extends TextField
{
private long m_digit;
public FXNDigitsField()
{
    super();
}
public FXNDigitsField(long number)
{
    super();
    this.m_digit = number;
    onInitialization();
}

private void onInitialization()
{
    setText(Long.toString(this.m_digit));
}

@Override
public void replaceText(int startIndex, int endIndex, String text)
{
    if (text.matches(Constants.DIGITS_PATTERN) || text.equals(Constants.EMPTY_STRING)) {
        super.replaceText(startIndex, endIndex, text);
    }
}

@Override
public void replaceSelection(String text)
{
    if (text.matches(Constants.DIGITS_PATTERN) || text.equals(Constants.EMPTY_STRING)) {
        super.replaceSelection(text);
    }
}
}

第二种方式是添加事件过滤器。

And the second way is by adding an event Filter.

给出了代码片段。

 // restrict key input to numerals.
this.addEventFilter(KeyEvent.KEY_TYPED, new EventHandler<KeyEvent>() {
  @Override public void handle(KeyEvent keyEvent) {
    if (!"0123456789".contains(keyEvent.getCharacter())) {
      keyEvent.consume();
    }
  }
});

我的问题是诽谤的方式是什么？任何人都可以帮我挑选合适的人吗？

My question is which is the slandered way to do this? Can anyone help me to pick up the right?

推荐答案

在TextField中添加验证的最佳方法是第三种方式。
此方法允许TextField完成所有处理（复制/粘贴/撤消安全）。
它不要求您扩展TextField类。
它允许您决定在每次更改
之后如何处理新文本（将其推送到逻辑，或者返回到先前的值，甚至修改它）。

The best way to add validation in TextField is a 3rd way. This method lets TextField finish all processing (copy/paste/undo safe). It does not require you to extend the TextField class. And it allows you to decide what to do with new text after every change (to push it to logic, or turn back to previous value, or even to modify it).

// fired by every text property changes
textField.textProperty().addListener(
  (observable, oldValue, newValue) -> {
    // Your validation rules, anything you like
    // (! note 1 !) make sure that empty string (newValue.equals("")) 
    //   or initial text is always valid
    //   to prevent inifinity cycle
    // do whatever you want with newValue

    // If newValue is not valid for your rules
    ((StringProperty)observable).setValue(oldValue);
    // (! note 2 !) do not bind textProperty (textProperty().bind(someProperty))
    //   to anything in your code.  TextProperty implementation
    //   of StringProperty in TextFieldControl
    //   will throw RuntimeException in this case on setValue(string) call.
    //   Or catch and handle this exception.

    // If you want to change something in text
    // When it is valid for you with some changes that can be automated.
    // For example change it to upper case
    ((StringProperty)observable).setValue(newValue.toUpperCase());
  }
);

这篇关于建议在JavaFX文本字段中限制输入的方法的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！