如何在输入验证期间显示临时气球工具提示？

Question

我有点习惯 GUI 习惯用法，当我在文本输入字段中输入错误的内容时，该字段会弹出一个气球，其中包含有关我错误/预期输入的信息。它保持可见，直到我再次输入。 但现在我找不到任何例子可以指出。

给定一个 JTextfield，你知道有什么库/代码会在我的按键侦听器触发时显示这样的气球吗？

@参见http://www.javapractices.com/topic/TopicAction.do?Id=151

Answer 1

Balloon Tip（在 Maven Central 上可用）是一个可以实现此目的的库：

balloonTip = new BalloonTip(f, "Tooltip msg");

这就是所需要的！如果您坚持将其也作为工具提示：

tooltipBalloon = new BalloonTip(someComponent, "I'm a balloon tooltip!");
// Now convert this balloon tip to a tooltip, such that the tooltip shows up after 500 milliseconds and stays visible for 3000 milliseconds
ToolTipUtils.balloonToToolTip(tooltipBalloon, 500, 3000);

Answer 2

James Poulson 给出的链接可能提供了更好的解决方案，但我必须看看这是否可以通过使用 DocumentFilter 和 JWindow 的一些简单 Java 代码来实现。这是一种可能的方法：

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Point;
import java.awt.Window;
import javax.swing.*;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.DocumentFilter;
import javax.swing.text.PlainDocument;

public class InfoBalloon extends JPanel {
   private static final int PREF_WIDTH = 400;
   private static final int PREF_HEIGHT = 300;
   private static final String REGEX_TEST = "\\d*";
   private static final String ERROR_TEXT = "Please only add numbers to the text field";
   private JTextField textField = new JTextField(10);
   private JWindow errorWindow;


   public InfoBalloon() {
      add(new JLabel("Please Enter Number"));
      add(textField);

      ((PlainDocument)textField.getDocument()).setDocumentFilter(new MyNumberDocFilter());
   }

   @Override
   public Dimension getPreferredSize() {
      return new Dimension(PREF_WIDTH, PREF_HEIGHT);
   }

   private void showErrorWin() {     
      if (errorWindow == null) {
         JLabel errorLabel = new JLabel(ERROR_TEXT);
         Window topLevelWin = SwingUtilities.getWindowAncestor(this);
         errorWindow = new JWindow(topLevelWin);
         JPanel contentPane = (JPanel) errorWindow.getContentPane();
         contentPane.add(errorLabel);
         contentPane.setBackground(Color.white);
         contentPane.setBorder(BorderFactory.createLineBorder(Color.LIGHT_GRAY));
         errorWindow.pack();
      }

      Point loc = textField.getLocationOnScreen();
      errorWindow.setLocation(loc.x + 20, loc.y + 30);
      errorWindow.setVisible(true);
   }

   private boolean textOK(String text) {
      if (text.matches(REGEX_TEST)) {
         return true;
      }
      return false;
   }

   private class MyNumberDocFilter extends DocumentFilter {
      @Override
      public void insertString(FilterBypass fb, int offset, String string,
               AttributeSet attr) throws BadLocationException {
         if (textOK(string)) {
            super.insertString(fb, offset, string, attr);
            if (errorWindow != null && errorWindow.isVisible()) {
               errorWindow.setVisible(false);
            }
         } else {
            showErrorWin();
         }
      }

      @Override
      public void replace(FilterBypass fb, int offset, int length, String text,
               AttributeSet attrs) throws BadLocationException {
         if (textOK(text)) {
            super.replace(fb, offset, length, text, attrs);
            if (errorWindow != null && errorWindow.isVisible()) {
               errorWindow.setVisible(false);
            }
         } else {
            showErrorWin();
         }
      }

      @Override
      public void remove(FilterBypass fb, int offset, int length)
               throws BadLocationException {
         super.remove(fb, offset, length);
         if (errorWindow != null && errorWindow.isVisible()) {
            errorWindow.setVisible(false);
         }
      }
   }

   private static void createAndShowUI() {
      JFrame frame = new JFrame("Info Balloon");
      frame.getContentPane().add(new InfoBalloon());
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.pack();
      frame.setLocationRelativeTo(null);
      frame.setVisible(true);
   }

   public static void main(String[] args) {
      java.awt.EventQueue.invokeLater(new Runnable() {
         public void run() {
            createAndShowUI();
         }
      });
   }
}

欢迎建设性或破坏性的批评！