Question

我正在使用LostFocus事件验证两个文本字段，如下所示：

textRegNo.addFocusListener(new FocusListener() {            
        @Override
        public void focusLost(FocusEvent arg0) {
            // TODO Auto-generated method stub
            regNo1=textRegNo.getText();
            Pattern pattern1 = Pattern.compile("^[A-Z]{2}[ -][0-9]{1,2}(?: [A-Z])?(?: [A-Z]*)? [0-9]{4}$");
            Matcher matcher1 = pattern1.matcher(regNo1);

            if (!matcher1.find()){
                JOptionPane.showMessageDialog(null, "Invalid Vehicle No!!!\n Vehicle no should be of the form MH 03 KS 2131!!");
            }                           
        }
        @Override
        public void focusGained(FocusEvent arg0) {
            // TODO Auto-generated method stub

        };
    }); 


textMobNo.addFocusListener(new FocusListener() {            
        @Override
        public void focusLost(FocusEvent arg0) {
            // TODO Auto-generated method stub
            mobNo1=textMobNo.getText();
            Pattern pattern2 = Pattern.compile("^[789]\\d{9}$");
            Matcher matcher2 = pattern2.matcher(mobNo1);

            System.out.println("'"+mobNo1+"'");
            if (!matcher2.find()){
                JOptionPane.showMessageDialog(null, "Phone no must be a 10 digit number!!");
            }                           
        }

        @Override
        public void focusGained(FocusEvent arg0) {
            // TODO Auto-generated method stub

        };
    });

我的问题是，当我失去对第一个文本字段的关注并将焦点移动到第二个文本字段时，将为两个字段打印错误消息（两个lostfocus事件下的IF块内的MESSAGE）。当我向第一个文本字段输入错误的输入并将焦点移动到第二个字段时，它应该只打印第一个文本字段的错误消息。但它的打印错误。

第一个文本字段是textRegNo 第二个文本字段是textMobNo

Answer 1

问题的症状围绕着这个过程。

textMobNo获得关注......
会导致textRegNo失去焦点......
textRegNo已经过验证且发现无效，textRegNo现在显示错误消息...
焦点转移到对话框并......
textMobNo失去焦点（因为对话获得了焦点）

如果可以，您应该避免使用焦点作为验证字段的方法，而是使用InputVerifier

简单示例

import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.swing.InputVerifier;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.text.JTextComponent;

public class TestInputVerifier {

    public static void main(String[] args) {
        new TestInputVerifier();
    }

    public TestInputVerifier() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        public TestPane() {
            GridBagConstraints gbc = new GridBagConstraints();
            gbc.gridwidth = GridBagConstraints.REMAINDER;
            JTextField field = new JTextField(20);
            field.setInputVerifier(new RegExpInputVerifier("^[A-Z]{2}[ -][0-9]{1,2}(?: [A-Z])?(?: [A-Z]*)? [0-9]{4}$"));
            add(field, gbc);

            field = new JTextField(20);
            field.setInputVerifier(new RegExpInputVerifier("^[789]\\d{9}$"));
            add(field, gbc);
        }

    }

    public class RegExpInputVerifier extends InputVerifier {

        private String expression;

        public RegExpInputVerifier(String expression) {
            this.expression = expression;
        }

        public String getExpression() {
            return expression;
        }

        @Override
        public boolean verify(JComponent input) {
            boolean verified = false;
            if (input instanceof JTextComponent) {
                JTextComponent field = (JTextComponent) input;
                String regNo1 = field.getText();
                Pattern pattern1 = Pattern.compile(expression);
                Matcher matcher1 = pattern1.matcher(regNo1);
            }
            return verified;
        }
    }
}

使用LostFocus事件在Java中进行文本字段验证

1 个答案: