Question

I would like to add a hint value to my javax.swing.JTextField. It should look like Firefox rendering of <input type="text" title="bla">. This creates an edit field with the text bla in the background. If the textbox has focus the title-text disappears and just reappears if the user leaves the editbox without text.

Is there a (free) swing component that does something like this?

Answer 1

Take a look at this one: http://code.google.com/p/xswingx/

It is not very difficult to implement it by yourself, btw. A couple of listeners and custom renderer and voila.

Answer 2

You could create your own:

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;
import javax.swing.*;

public class Main {

  public static void main(String[] args) {

    final JFrame frame = new JFrame();

    frame.setLayout(new BorderLayout());

    final JTextField textFieldA = new HintTextField("A hint here");
    final JTextField textFieldB = new HintTextField("Another hint here");

    frame.add(textFieldA, BorderLayout.NORTH);
    frame.add(textFieldB, BorderLayout.CENTER);
    JButton btnGetText = new JButton("Get text");

    btnGetText.addActionListener(new ActionListener() {
      @Override
      public void actionPerformed(ActionEvent e) {
        String message = String.format("textFieldA= %s , textFieldB= %s ",
            textFieldA.getText(), textFieldB.getText());
        JOptionPane.showMessageDialog(frame, message);
      }
    });

    frame.add(btnGetText, BorderLayout.SOUTH);
    frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    frame.setVisible(true);
    frame.pack();
  }
}

class HintTextField extends JTextField implements FocusListener {

  private final String hint;
  private boolean showingHint;

  public HintTextField(final String hint) {
    super(hint);
    this.hint = hint;
    this.showingHint = true;
    super.addFocusListener(this);
  }

  @Override
  public void focusGained(FocusEvent e) {
    if(this.getText().isEmpty()) {
      super.setText("");
      showingHint = false;
    }
  }
  @Override
  public void focusLost(FocusEvent e) {
    if(this.getText().isEmpty()) {
      super.setText(hint);
      showingHint = true;
    }
  }

  @Override
  public String getText() {
    return showingHint ? "" : super.getText();
  }
}

If you re still on Java 1.5, replace the this.getText().isEmpty() with this.getText().length() == 0.

Answer 3

Here is a simple way that looks good in any L&F:

public class HintTextField extends JTextField {
    public HintTextField(String hint) {
        _hint = hint;
    }
    @Override
    public void paint(Graphics g) {
        super.paint(g);
        if (getText().length() == 0) {
            int h = getHeight();
            ((Graphics2D)g).setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING,RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
            Insets ins = getInsets();
            FontMetrics fm = g.getFontMetrics();
            int c0 = getBackground().getRGB();
            int c1 = getForeground().getRGB();
            int m = 0xfefefefe;
            int c2 = ((c0 & m) >>> 1) + ((c1 & m) >>> 1);
            g.setColor(new Color(c2, true));
            g.drawString(_hint, ins.left, h / 2 + fm.getAscent() / 2 - 2);
        }
    }
    private final String _hint;
}

Answer 4

Here is a single class copy/paste solution:

import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;

import javax.swing.plaf.basic.BasicTextFieldUI;
import javax.swing.text.JTextComponent;


public class HintTextFieldUI extends BasicTextFieldUI implements FocusListener {

    private String hint;
    private boolean hideOnFocus;
    private Color color;

    public Color getColor() {
        return color;
    }

    public void setColor(Color color) {
        this.color = color;
        repaint();
    }

    private void repaint() {
        if(getComponent() != null) {
            getComponent().repaint();           
        }
    }

    public boolean isHideOnFocus() {
        return hideOnFocus;
    }

    public void setHideOnFocus(boolean hideOnFocus) {
        this.hideOnFocus = hideOnFocus;
        repaint();
    }

    public String getHint() {
        return hint;
    }

    public void setHint(String hint) {
        this.hint = hint;
        repaint();
    }
    public HintTextFieldUI(String hint) {
        this(hint,false);
    }

    public HintTextFieldUI(String hint, boolean hideOnFocus) {
        this(hint,hideOnFocus, null);
    }

    public HintTextFieldUI(String hint, boolean hideOnFocus, Color color) {
        this.hint = hint;
        this.hideOnFocus = hideOnFocus;
        this.color = color;
    }

    @Override
    protected void paintSafely(Graphics g) {
        super.paintSafely(g);
        JTextComponent comp = getComponent();
        if(hint!=null && comp.getText().length() == 0 && (!(hideOnFocus && comp.hasFocus()))){
            if(color != null) {
                g.setColor(color);
            } else {
                g.setColor(comp.getForeground().brighter().brighter().brighter());              
            }
            int padding = (comp.getHeight() - comp.getFont().getSize())/2;
            g.drawString(hint, 2, comp.getHeight()-padding-1);          
        }
    }

    @Override
    public void focusGained(FocusEvent e) {
        if(hideOnFocus) repaint();

    }

    @Override
    public void focusLost(FocusEvent e) {
        if(hideOnFocus) repaint();
    }
    @Override
    protected void installListeners() {
        super.installListeners();
        getComponent().addFocusListener(this);
    }
    @Override
    protected void uninstallListeners() {
        super.uninstallListeners();
        getComponent().removeFocusListener(this);
    }
}

Use it like this:

TextField field = new JTextField();
field.setUI(new HintTextFieldUI("Search", true));

Note that it is happening in protected void paintSafely(Graphics g).

Answer 5

For any Swing component (that is, anything that extends JComponent), you can call the setToolTipText(String) method.

For more information, reference the following links:

Answer 6

Have look at WebLookAndFeel at https://github.com/mgarin/weblaf/

WebTextField txtName = new com.alee.laf.text.WebTextField();

txtName.setHideInputPromptOnFocus(false);

txtName.setInputPrompt("Name");

txtName.setInputPromptFont(new java.awt.Font("Ubuntu", 0, 18));

txtName.setInputPromptForeground(new java.awt.Color(102, 102, 102));

txtName.setInputPromptPosition(0);

Answer 7

If you still look for a solution, here s one that combined other answers (Bart Kiers and culmat) for your reference:

import javax.swing.*;
import javax.swing.text.JTextComponent;
import java.awt.*;
import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;


public class HintTextField extends JTextField implements FocusListener
{

    private String hint;

    public HintTextField ()
    {
        this("");
    }

    public HintTextField(final String hint)
    {
        setHint(hint);
        super.addFocusListener(this);
    }

    public void setHint(String hint)
    {
        this.hint = hint;
        setUI(new HintTextFieldUI(hint, true));
        //setText(this.hint);
    }


    public void focusGained(FocusEvent e)
    {
        if(this.getText().length() == 0)
        {
            super.setText("");
        }
    }

    public void focusLost(FocusEvent e)
    {
        if(this.getText().length() == 0)
        {
            setHint(hint);
        }
    }

    public String getText()
    {
        String typed = super.getText();
        return typed.equals(hint)?"":typed;
    }
}

class HintTextFieldUI extends javax.swing.plaf.basic.BasicTextFieldUI implements FocusListener
{

    private String hint;
    private boolean hideOnFocus;
    private Color color;

    public Color getColor()
    {
        return color;
    }

    public void setColor(Color color)
    {
        this.color = color;
        repaint();
    }

    private void repaint()
    {
        if(getComponent() != null)
        {
            getComponent().repaint();
        }
    }

    public boolean isHideOnFocus()
    {
        return hideOnFocus;
    }

    public void setHideOnFocus(boolean hideOnFocus)
    {
        this.hideOnFocus = hideOnFocus;
        repaint();
    }

    public String getHint()
    {
        return hint;
    }

    public void setHint(String hint)
    {
        this.hint = hint;
        repaint();
    }

    public HintTextFieldUI(String hint)
    {
        this(hint, false);
    }

    public HintTextFieldUI(String hint, boolean hideOnFocus)
    {
        this(hint, hideOnFocus, null);
    }

    public HintTextFieldUI(String hint, boolean hideOnFocus, Color color)
    {
        this.hint = hint;
        this.hideOnFocus = hideOnFocus;
        this.color = color;
    }


    protected void paintSafely(Graphics g)
    {
        super.paintSafely(g);
        JTextComponent comp = getComponent();
        if(hint != null && comp.getText().length() == 0 && (!(hideOnFocus && comp.hasFocus())))
        {
            if(color != null)
            {
                g.setColor(color);
            }
            else
            {
                g.setColor(Color.gray);
            }
            int padding = (comp.getHeight() - comp.getFont().getSize()) / 2;
            g.drawString(hint, 5, comp.getHeight() - padding - 1);
        }
    }


    public void focusGained(FocusEvent e)
    {
        if(hideOnFocus) repaint();

    }


    public void focusLost(FocusEvent e)
    {
        if(hideOnFocus) repaint();
    }

    protected void installListeners()
    {
        super.installListeners();
        getComponent().addFocusListener(this);
    }

    protected void uninstallListeners()
    {
        super.uninstallListeners();
        getComponent().removeFocusListener(this);
    }
}



Usage:
HintTextField field = new HintTextField();
field.setHint("Here s a hint");

Answer 8

This can be achieved by using a focus listener to update the text field content.

Make the class implement the focus listener interface:

class YourClass implements FocusListener

Add a method to catch when focus is gained that blanks the field:

public void focusGained(FocusEvent e) {
    if(JTextField1.getText().equals("Username")) {
        JTextField1.setText("");
    }
}

Add a method to catch when focus is lost to redisplay the default entry if the field was blank:

public void focusLost(FocusEvent e) {
    if(JTextField1.getText().equals("")) {
        JTextField1.setText("Username");
        // you should prevent the form from being processed in this state
        // as it will literally contain "Username" for the username
    }
}

Register your class as the focus listener for text field:

textField.addFocusListener(this);

Learn more at How to Write a Focus Listener in the Java Tutorials.

Answer 9

Here is a fully working example based on Adam Gawne-Cain s earlier Posting. His solution is simple and actually works exceptionally well.

I ve used the following text in a Grid of multiple Fields:

H__|__WWW__+__XXXX__+__WWW__|__H

this makes it possible to easily verify the x/y alignment of the hinted text.

A couple of observations:
- there are any number of solutions out there, but many only work superficially and/or are buggy
- sun.tools.jconsole.ThreadTab.PromptingTextField is a simple solution, but it only shows the prompting text when the Field doesn t have the focus & it s private, but nothing a little cut-and-paste won t fix.

The following works on JDK 8 and upwards:

import java.awt.*;
import java.util.stream.*;
import javax.swing.*;
/**
 * @author DaveTheDane, based on a suggestion from Adam Gawne-Cain
 */
public final class JTextFieldPromptExample extends JFrame {

    private static JTextField newPromptedJTextField (final String text, final String prompt) {

        final String promptPossiblyNullButNeverWhitespace = prompt == null || prompt.trim().isEmpty()  ?  null  :  prompt;

        return new JTextField(text) {
            @Override
            public void paintComponent(final Graphics    USE_g2d_INSTEAD) {
                final Graphics2D     g2d =  (Graphics2D) USE_g2d_INSTEAD;

                super.paintComponent(g2d);

//              System.out.println("Paint.: " + g2d);

                if (getText().isEmpty()
                &&  promptPossiblyNullButNeverWhitespace != null) {
                    g2d.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);

                    final Insets      ins = getInsets();
                    final FontMetrics fm  = g2d.getFontMetrics();

                    final int cB = getBackground().getRGB();
                    final int cF = getForeground().getRGB();
                    final int m  = 0xfefefefe;
                    final int c2 = ((cB & m) >>> 1) + ((cF & m) >>> 1); // "for X in (A, R, G, B) {Xnew = (Xb + Xf) / 2}"
                    /*
                     * The hint text color should be halfway between the foreground and background colors so it is always gently visible.
                     * The variables c0,c1,m,c2 calculate the halfway color s ARGB fields simultaneously without overflowing 8 bits.
                     * Swing sets the Graphics  font to match the JTextField s font property before calling the "paint" method,
                     * so the hint font will match the JTextField s font.
                     * Don t think there are any side effects because Swing discards the Graphics after painting.
                     * Adam Gawne-Cain, Aug 6 2019 at 15:55
                     */
                    g2d.setColor(new Color(c2, true));
                    g2d.drawString(promptPossiblyNullButNeverWhitespace, ins.left, getHeight() - fm.getDescent() - ins.bottom);
                    /*
                     * y Coordinate based on Descent & Bottom-inset seems to align Text spot-on.
                     * DaveTheDane, Apr 10 2020
                     */
                }
            }
        };
    }

    private static final GridBagConstraints GBC_LEFT  = new GridBagConstraints();
    private static final GridBagConstraints GBC_RIGHT = new GridBagConstraints();
    /**/    static {
        GBC_LEFT .anchor    = GridBagConstraints.LINE_START;
        GBC_LEFT .fill      = GridBagConstraints.HORIZONTAL;
        GBC_LEFT .insets    = new Insets(8, 8, 0, 0);

        GBC_RIGHT.gridwidth = GridBagConstraints.REMAINDER;
        GBC_RIGHT.fill      = GridBagConstraints.HORIZONTAL;
        GBC_RIGHT.insets    = new Insets(8, 8, 0, 8);
    }

    private <C extends Component> C addLeft (final C component) {
        this    .add           (component);
        this.gbl.setConstraints(component, GBC_LEFT);
        return                  component;
    }
    private <C extends Component> C addRight(final C component) {
        this    .add           (component);
        this.gbl.setConstraints(component, GBC_RIGHT);
        return                  component;
    }

    private static final String ALIGN = "H__|__WWW__+__XXXX__+__WWW__|__H";

    private final GridBagLayout gbl = new GridBagLayout();

    public JTextFieldPromptExample(final String title) {
        super(title);
        this.setLayout(gbl);

        final java.util.List<JTextField> texts = Stream.of(
                addLeft (newPromptedJTextField(ALIGN +     + "Top-Left"    , ALIGN)),
                addRight(newPromptedJTextField(ALIGN +     + "Top-Right"   , ALIGN)),

                addLeft (newPromptedJTextField(ALIGN +     + "Middle-Left" , ALIGN)),
                addRight(newPromptedJTextField(                       null , ALIGN)),

                addLeft (new        JTextField("x"        )),
                addRight(newPromptedJTextField("x",   ""  )),

                addLeft (new        JTextField(null       )),
                addRight(newPromptedJTextField(null,  null)),

                addLeft (newPromptedJTextField(ALIGN +     + "Bottom-Left" , ALIGN)),
                addRight(newPromptedJTextField(ALIGN +     + "Bottom-Right", ALIGN)) ).collect(Collectors.toList());

        final JButton button = addRight(new JButton("Get texts"));
        /**/                   addRight(Box.createVerticalStrut(0)); // 1 last time forces bottom inset

        this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        this.setPreferredSize(new Dimension(740, 260));
        this.pack();
        this.setResizable(false);
        this.setVisible(true);

        button.addActionListener(e -> {
            texts.forEach(text -> System.out.println("Text..: " + text.getText()));
        });
    }

    public static void main(final String[] args) {
        SwingUtilities.invokeLater(() -> new JTextFieldPromptExample("JTextField with Prompt"));
    }
}

友情链接