How to implement hover help feedback using the MouseTrackListener : Mouse Key « SWT JFace Eclipse « Java






How to implement hover help feedback using the MouseTrackListener

How to implement hover help feedback using the MouseTrackListener


import java.io.IOException;
import java.io.InputStream;
import java.text.MessageFormat;
import java.util.MissingResourceException;
import java.util.ResourceBundle;

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.DisposeEvent;
import org.eclipse.swt.events.DisposeListener;
import org.eclipse.swt.events.HelpEvent;
import org.eclipse.swt.events.HelpListener;
import org.eclipse.swt.events.MouseAdapter;
import org.eclipse.swt.events.MouseEvent;
import org.eclipse.swt.events.MouseTrackAdapter;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.ImageData;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Item;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Table;
import org.eclipse.swt.widgets.TableItem;
import org.eclipse.swt.widgets.ToolBar;
import org.eclipse.swt.widgets.ToolItem;
import org.eclipse.swt.widgets.Tree;
import org.eclipse.swt.widgets.TreeItem;
import org.eclipse.swt.widgets.Widget;

/**
 * This example demonstrates how to implement hover help feedback using the
 * MouseTrackListener.
 */
public class HoverHelp {
  static final int hhiInformation = 0, hhiWarning = 1;

  static final String[] imageLocations = { "information.gif", "warning.gif" };

  Image images[];

  /**
   * Runs main program.
   */
  public static void main(String[] args) {
    Display display = new Display();
    Shell shell = new HoverHelp().open(display);
    // Event loop
    while (shell != null && !shell.isDisposed()) {
      if (!display.readAndDispatch())
        display.sleep();
    }
    // Cleanup
    display.dispose();

  }

  /**
   * Opens the main program.
   */
  public Shell open(Display display) {
    // Load the images
    Class clazz = HoverHelp.class;
    try {
      if (images == null) {
        images = new Image[imageLocations.length];

        for (int i = 0; i < imageLocations.length; ++i) {
          InputStream stream = clazz
              .getResourceAsStream(imageLocations[i]);
          ImageData source = new ImageData(stream);
          ImageData mask = source.getTransparencyMask();
          images[i] = new Image(display, source, mask);
          try {
            stream.close();
          } catch (IOException e) {
            e.printStackTrace();
          }
        }
      }
    } catch (Exception ex) {
      System.err.println(getResourceString("error.CouldNotLoadResources",
          new Object[] { ex.getMessage() }));
      return null;
    }

    // Create the window
    Shell shell = new Shell();
    createPartControl(shell);
    shell.addDisposeListener(new DisposeListener() {
      public void widgetDisposed(DisposeEvent e) {
        /* Free resources */
        if (images != null) {
          for (int i = 0; i < images.length; i++) {
            final Image image = images[i];
            if (image != null)
              image.dispose();
          }
          images = null;
        }
      }
    });
    shell.pack();
    shell.open();
    return shell;
  }

  /**
   * Gets a string from the resource bundle. We don't want to crash because of
   * a missing String. Returns the key if not found.
   */
  public String getResourceString(String key) {
      return key;
  }

  /**
   * Gets a string from the resource bundle and binds it with the given
   * arguments. If the key is not found, return the key.
   */
  public String getResourceString(String key, Object[] args) {
    try {
      return MessageFormat.format(getResourceString(key), args);
    } catch (MissingResourceException e) {
      return key;
    } catch (NullPointerException e) {
      return "!" + key + "!";
    }
  }

  /**
   * Creates the example
   */
  public void createPartControl(Composite frame) {
    final ToolTipHandler tooltip = new ToolTipHandler(frame.getShell());

    GridLayout layout = new GridLayout();
    layout.numColumns = 3;
    frame.setLayout(layout);

    ToolBar bar = new ToolBar(frame, SWT.BORDER);
    for (int i = 0; i < 5; i++) {
      ToolItem item = new ToolItem(bar, SWT.PUSH);
      item.setText(getResourceString("ToolItem.text",
          new Object[] { new Integer(i) }));
      item.setData("TIP_TEXT", getResourceString("ToolItem.tooltip",
          new Object[] { item.getText() }));
      item.setData("TIP_HELPTEXTHANDLER", new ToolTipHelpTextHandler() {
        public String getHelpText(Widget widget) {
          Item item = (Item) widget;
          return getResourceString("ToolItem.help",
              new Object[] { item.getText() });
        }
      });
    }
    GridData gridData = new GridData();
    gridData.horizontalSpan = 3;
    bar.setLayoutData(gridData);
    tooltip.activateHoverHelp(bar);

    Table table = new Table(frame, SWT.BORDER);
    for (int i = 0; i < 4; i++) {
      TableItem item = new TableItem(table, SWT.PUSH);
      item.setText(getResourceString("Item",
          new Object[] { new Integer(i) }));
      item.setData("TIP_IMAGE", images[hhiInformation]);
      item.setText(getResourceString("TableItem.text",
          new Object[] { new Integer(i) }));
      item.setData("TIP_TEXT", getResourceString("TableItem.tooltip",
          new Object[] { item.getText() }));
      item.setData("TIP_HELPTEXTHANDLER", new ToolTipHelpTextHandler() {
        public String getHelpText(Widget widget) {
          Item item = (Item) widget;
          return getResourceString("TableItem.help",
              new Object[] { item.getText() });
        }
      });
    }
    table.setLayoutData(new GridData(GridData.VERTICAL_ALIGN_FILL));
    tooltip.activateHoverHelp(table);

    Tree tree = new Tree(frame, SWT.BORDER);
    for (int i = 0; i < 4; i++) {
      TreeItem item = new TreeItem(tree, SWT.PUSH);
      item.setText(getResourceString("Item",
          new Object[] { new Integer(i) }));
      item.setData("TIP_IMAGE", images[hhiWarning]);
      item.setText(getResourceString("TreeItem.text",
          new Object[] { new Integer(i) }));
      item.setData("TIP_TEXT", getResourceString("TreeItem.tooltip",
          new Object[] { item.getText() }));
      item.setData("TIP_HELPTEXTHANDLER", new ToolTipHelpTextHandler() {
        public String getHelpText(Widget widget) {
          Item item = (Item) widget;
          return getResourceString("TreeItem.help",
              new Object[] { item.getText() });
        }
      });
    }
    tree.setLayoutData(new GridData(GridData.VERTICAL_ALIGN_FILL));
    tooltip.activateHoverHelp(tree);

    Button button = new Button(frame, SWT.PUSH);
    button.setText(getResourceString("Hello.text"));
    button.setData("TIP_TEXT", getResourceString("Hello.tooltip"));
    tooltip.activateHoverHelp(button);
  }

  /**
   * Emulated tooltip handler Notice that we could display anything in a
   * tooltip besides text and images. For instance, it might make sense to
   * embed large tables of data or buttons linking data under inspection to
   * material elsewhere, or perform dynamic lookup for creating tooltip text
   * on the fly.
   */
  protected static class ToolTipHandler {
    private Shell parentShell;

    private Shell tipShell;

    private Label tipLabelImage, tipLabelText;

    private Widget tipWidget; // widget this tooltip is hovering over

    private Point tipPosition; // the position being hovered over

    /**
     * Creates a new tooltip handler
     * 
     * @param parent
     *            the parent Shell
     */
    public ToolTipHandler(Shell parent) {
      final Display display = parent.getDisplay();
      this.parentShell = parent;

      tipShell = new Shell(parent, SWT.ON_TOP | SWT.TOOL);
      GridLayout gridLayout = new GridLayout();
      gridLayout.numColumns = 2;
      gridLayout.marginWidth = 2;
      gridLayout.marginHeight = 2;
      tipShell.setLayout(gridLayout);

      tipShell.setBackground(display
          .getSystemColor(SWT.COLOR_INFO_BACKGROUND));

      tipLabelImage = new Label(tipShell, SWT.NONE);
      tipLabelImage.setForeground(display
          .getSystemColor(SWT.COLOR_INFO_FOREGROUND));
      tipLabelImage.setBackground(display
          .getSystemColor(SWT.COLOR_INFO_BACKGROUND));
      tipLabelImage.setLayoutData(new GridData(GridData.FILL_HORIZONTAL
          | GridData.VERTICAL_ALIGN_CENTER));

      tipLabelText = new Label(tipShell, SWT.NONE);
      tipLabelText.setForeground(display
          .getSystemColor(SWT.COLOR_INFO_FOREGROUND));
      tipLabelText.setBackground(display
          .getSystemColor(SWT.COLOR_INFO_BACKGROUND));
      tipLabelText.setLayoutData(new GridData(GridData.FILL_HORIZONTAL
          | GridData.VERTICAL_ALIGN_CENTER));
    }

    /**
     * Enables customized hover help for a specified control
     * 
     * @control the control on which to enable hoverhelp
     */
    public void activateHoverHelp(final Control control) {
      /*
       * Get out of the way if we attempt to activate the control
       * underneath the tooltip
       */
      control.addMouseListener(new MouseAdapter() {
        public void mouseDown(MouseEvent e) {
          if (tipShell.isVisible())
            tipShell.setVisible(false);
        }
      });

      /*
       * Trap hover events to pop-up tooltip
       */
      control.addMouseTrackListener(new MouseTrackAdapter() {
        public void mouseExit(MouseEvent e) {
          if (tipShell.isVisible())
            tipShell.setVisible(false);
          tipWidget = null;
        }

        public void mouseHover(MouseEvent event) {
          Point pt = new Point(event.x, event.y);
          Widget widget = event.widget;
          if (widget instanceof ToolBar) {
            ToolBar w = (ToolBar) widget;
            widget = w.getItem(pt);
          }
          if (widget instanceof Table) {
            Table w = (Table) widget;
            widget = w.getItem(pt);
          }
          if (widget instanceof Tree) {
            Tree w = (Tree) widget;
            widget = w.getItem(pt);
          }
          if (widget == null) {
            tipShell.setVisible(false);
            tipWidget = null;
            return;
          }
          if (widget == tipWidget)
            return;
          tipWidget = widget;
          tipPosition = control.toDisplay(pt);
          String text = (String) widget.getData("TIP_TEXT");
          Image image = (Image) widget.getData("TIP_IMAGE");
          tipLabelText.setText(text != null ? text : "");
          tipLabelImage.setImage(image); // accepts null
          tipShell.pack();
          setHoverLocation(tipShell, tipPosition);
          tipShell.setVisible(true);
        }
      });

      /*
       * Trap F1 Help to pop up a custom help box
       */
      control.addHelpListener(new HelpListener() {
        public void helpRequested(HelpEvent event) {
          if (tipWidget == null)
            return;
          ToolTipHelpTextHandler handler = (ToolTipHelpTextHandler) tipWidget
              .getData("TIP_HELPTEXTHANDLER");
          if (handler == null)
            return;
          String text = handler.getHelpText(tipWidget);
          if (text == null)
            return;

          if (tipShell.isVisible()) {
            tipShell.setVisible(false);
            Shell helpShell = new Shell(parentShell, SWT.SHELL_TRIM);
            helpShell.setLayout(new FillLayout());
            Label label = new Label(helpShell, SWT.NONE);
            label.setText(text);
            helpShell.pack();
            setHoverLocation(helpShell, tipPosition);
            helpShell.open();
          }
        }
      });
    }

    /**
     * Sets the location for a hovering shell
     * 
     * @param shell
     *            the object that is to hover
     * @param position
     *            the position of a widget to hover over
     * @return the top-left location for a hovering box
     */
    private void setHoverLocation(Shell shell, Point position) {
      Rectangle displayBounds = shell.getDisplay().getBounds();
      Rectangle shellBounds = shell.getBounds();
      shellBounds.x = Math.max(Math.min(position.x, displayBounds.width
          - shellBounds.width), 0);
      shellBounds.y = Math.max(Math.min(position.y + 16,
          displayBounds.height - shellBounds.height), 0);
      shell.setBounds(shellBounds);
    }
  }

  /**
   * ToolTip help handler
   */
  protected interface ToolTipHelpTextHandler {
    /**
     * Get help text
     * 
     * @param widget
     *            the widget that is under help
     * @return a help text string
     */
    public String getHelpText(Widget widget);
  }
}


           
       








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