Java Swing：实现输入值的有效性检查 [英] Java Swing: Implementing a validity check of input values

问题描述

在我的Swing应用程序中，用户必须插入数字和值，然后才能切换到下一个窗口。现在作为一个干净的程序，我检查每个输入是否有效，如果没有，则显示错误消息，下一个窗口不打开。

In my Swing application, the user must insert numbers and values, before switching to the next window. Now as a clean program should, I check every input if its valid or not, and if not, an error message is displayed and the next window does not open.

此检查的结构如下（示例）：

The structure of this check is as following (example):

Button buttonToOpenNextWindow = new JButton("next");
button.addActionListener(new ActionListener(){

    public void actionPerformed(ActionEvent e){
        if(checkValidty){
            // (...)
            new WindowA();
            frame.dispose(); // (*)
        }
    }
});

（*）注意：我知道多个JFrame的原理是丑陋，我正在改变这一点，但对于这个问题它是无关紧要的。

(*) Note: I know that the principle of multiple JFrames is ugly, and I'm on to change that, but for this question it's irrelevant.

现在这个问题的重点是这个 checkValidity（） ，我的结构如下：

Now the focus of this question is this checkValidity(), which I structured like this:

private boolean checkValidity(){

    // check input 1
    try{
        Integer.parseInt(textField1.getText());
    }catch (NumberFormatException e){
        new ErrorDialog("input 1 is invalid!"); // own implemented dialog
        return false;
    }

    // check input 2
    try{
        Integer.parseInt(textField2.getText());
    }catch (NumberFormatException e){
        new ErrorDialog("input 2 is invalid!"); // own implemented dialog
        return false;
    }

    // (...)

    // check input n
    try{
        Integer.parseInt(textField_n.getText());
    }catch (NumberFormatException e){
        new ErrorDialog("input n is invalid!"); // own implemented dialog
        return false;
    }
    return true;
}

这完全符合我的要求，但代码本身非常难看，因为具有多个输入选项，该方法获得200,300或更多行（因为我不仅检查它是否是数字，而且如果数字在程序逻辑的上下文中有意义等等）。是否有Swing -own方法来检查这些东西？或者有没有人更好地了解如何使用拆分方法实现这一功能？

This works exactly as I want, BUT the code itself is very ugly, because having multiple input options the method gets 200, 300 or more lines long (as I do not only check if e.g. it's a number, but also if the number makes sense in context of the program logic and so on). Is there a Swing -own method to check such things? Or has anyone a better idea how to realize exactly this functionality with split methods?

推荐答案

一种解决方案是使用Swing的 InputVerifier 验证所使用的每个 JTextField 的输入。由于每个字段的验证功能相同，因此单个实​​例可用于所有组件：

One solution would be to use Swing's InputVerifier to validate input for every JTextField used. As the validation functionality is the same for each field, a single instance could be used for all components:

public class MyNumericVerifier extends InputVerifier {
    @Override
    public boolean verify(JComponent input) {
       String text = ((JTextField) input).getText();
       try {
          Integer.parseInt(text);
       } catch (NumberFormatException e) {
          return false;
       }

       return true;
    }
}

InputVerifier verifier = new MyNumericVerifier()
textField1.setInputVerifier(verifier);

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