TreeItem实现Hyperlink的效果

在swt中，Hyperlink可以实现 '点击跳转' 的效果。例如，在PDE的MANIFEST.MF的 Activator 点击该标签可以跳转到对应的Activator的类。

org.eclipse.pde.internal.ui.editor.plugin.rows.ReferenceAttributeRow.createLabel(Composite, FormToolkit)

 

	protected void createLabel(Composite parent, FormToolkit toolkit) {
		if (!part.isEditable()) {
			super.createLabel(parent, toolkit);
			return;
		}

		Hyperlink link = toolkit.createHyperlink(parent, getPropertyLabel(), SWT.NULL);
		link.addHyperlinkListener(new HyperlinkAdapter() {
			public void linkActivated(HyperlinkEvent e) {
				if (!isReferenceModel()) {
					openReference(); // !!!Action
				} else {
					Display.getCurrent().beep();
				}
			}
		});
		PDETextHover.addHoverListenerToControl(fIC, link, this);
	}

 

 

如果需要在TreeItem上实现这样的效果需要怎么做呢？需要实现下面的UI显示：

1、 TreeItem的显示的Label需要有下划线

2、 文字颜色

在印象中，swt有一个paint的事件：SWT.Paint可以在发生paint事件，对元素UI进行重绘：

org.eclipse.swt.widgets.Control.addPaintListener(PaintListener)

 

public void addPaintListener (PaintListener listener) {
	checkWidget ();
	if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
	TypedListener typedListener = new TypedListener (listener);
	addListener (SWT.Paint,typedListener); //!!!
}

 

 但是TreeItem不是继承自Control。同时也没有重绘的事件发生。

Object

---Widget

------Item

---------TreeItem

 

在google后，找到了 http://www.iteye.com/topic/1113343 的文章，TreeItem可以通过Tree的SWT.PaintItem时来重绘。实现代码如下：

 

 

		// 1> 修改字体颜色
		this.tree.setForeground(toolkit.getColors().getColor(IFormColors.TITLE));
		
		tree.addSelectionListener(new SelectionAdapter() {
			@Override
			public void widgetSelected(SelectionEvent e) {
				if (e.detail == SWT.CHECK) {
					TreeItem item = (TreeItem) e.item;
					handleChanged((EObject) item.getData(), item.getChecked());
				} else {
					// 3> 点击open
					openReference(e.item.getData());
				}
			}
		});
		
		/**
		 * 2> 加下划线
		 */
		tree.addListener(SWT.PaintItem, new Listener() {
			public void handleEvent(Event event) {
				TreeItem item = (TreeItem) event.item;

				Rectangle bounds = item.getBounds();
				int textHeight = bounds.height;
				int textWidth = bounds.width;
				
				// 默认paint已经绘制了Text
				//event.gc.drawText(item.getText(), bounds.x, bounds.y, true);

				int descent = event.gc.getFontMetrics().getDescent();
				int lineY = bounds.y + textHeight - descent + 1;
				event.gc.drawLine(bounds.x, lineY, bounds.x + textWidth, lineY);
			}
		});

  

http://www.iteye.com/topic/1113343 写道

import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Tree;
import org.eclipse.swt.widgets.TreeItem;

public class Snippet300 {
	private static int IMAGE_MARGIN = 2;
	private static Image xImage;
	private static Display display;

	public static void main(String[] args) {
		display = new Display();
		Shell shell = new Shell(display);
		shell.setBounds(10, 10, 350, 200);
		createImage();
		final Tree tree = new Tree(shell, SWT.CHECK);
		tree.setBounds(10, 10, 300, 150);
		TreeItem item = new TreeItem(tree, SWT.NONE);
		item.setImage(xImage);
		item.setText("root item");
		for (int i = 0; i < 4; i++) {
			TreeItem newItem = new TreeItem(item, SWT.NONE);
			newItem.setText("descendent " + i);
			// if (i % 2 == 0) {
			// newItem.setData(xImage);
			// }
			newItem.setImage(xImage);
			item.setExpanded(true);
			item = newItem;
		}
		treeAddListener(tree);

		shell.open();
		while (!shell.isDisposed()) {
			if (!display.readAndDispatch())
				display.sleep();
		}
		xImage.dispose();
		display.dispose();
	}

	private static void createImage() {
		xImage = new Image(display, 16, 16);
		GC gc = new GC(xImage);
		gc.setForeground(display.getSystemColor(SWT.COLOR_RED));
		gc.drawLine(1, 1, 14, 14);
		gc.drawLine(1, 14, 14, 1);
		gc.drawOval(2, 2, 11, 11);
		gc.dispose();
	}

	private static void treeAddListener(final Tree tree) {
		Listener listener = new Listener() {
			public void handleEvent(Event event) {
				TreeItem item = (TreeItem) event.item;
				Image image = (Image) item.getImage();
				switch (event.type) {
				case SWT.MeasureItem: {
					if (image == null)
						break;
					event.width += 2 * (image.getBounds().width + IMAGE_MARGIN);
					break;
				}
				case SWT.EraseItem: {
					event.detail &= ~SWT.FOREGROUND;
					break;
				}
				case SWT.PaintItem: {
					if (image == null)
						break;
					int x, y;
					int itemH = tree.getItemHeight();
					int imageH = image.getBounds().height;
					int imageW = image.getBounds().width;

					// draw the 1 image
					x = event.x;
					y = event.y + (itemH - imageH) / 2;
					event.gc.drawImage(image, x, y);

					// draw the 2 image
					x += IMAGE_MARGIN + imageW;
					event.gc.drawImage(image, x, y);

					// draw the string
					String text = item.getText();
					x += IMAGE_MARGIN + imageW;
					y = event.y + 2;
					event.gc.drawText(text, x, y);

					// draw the 3 image
					x += event.width - imageW;
					y = event.y + (itemH - imageH) / 2;
					event.gc.drawImage(image, x, y);
					break;
				}
				}
			}
		};

		tree.addListener(SWT.MeasureItem, listener);
		tree.addListener(SWT.EraseItem, listener);
		tree.addListener(SWT.PaintItem, listener);
	}
}

 

评论

1 楼 cutesunshineriver 2012-04-01