[英]Change mouse cursor on hover over node in JTree
我正在創建一個JTree並添加一些節點做這樣的事情：
DefaultMutableTreeNode top = new DefaultMutableTreeNode("The Java Series");
tree = new JTree(top);
...
DefaultMutableTreeNode node = new DefaultMutableTreeNode("<html><a href=\" \">"+code+"</a> "+description+"</html>");
top.add(node);
...
現在我向節點添加了一個“addMouseMotionListener”，這是好的。 我的問題是，只要我將鼠標懸停在節點的任何部分上，鼠標光標就會改變。 我真正想要的是僅當鼠標懸停在節點的HTML超鏈接文本部分上時才更改鼠標光標
"<a href=\"\">"+code+"</a>"
而不是描述。
那么有沒有辦法讓鼠標光標只在懸停在節點的某些部分時改變？
提前致謝。
好吧，我花了一段時間，但我在評論中描述的內容似乎有效。 可能有其他/更好的方式，我很樂意閱讀它，但到目前為止，這是我發現的全部。
這個想法是：
這是代碼，作為獎勵，您還可以獲得工作超鏈接！
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Cursor;
import java.awt.Desktop;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import javax.swing.JEditorPane;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.text.AttributeSet;
import javax.swing.text.Element;
import javax.swing.text.html.HTML;
import javax.swing.text.html.HTMLDocument;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeCellRenderer;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.TreeCellRenderer;
import javax.swing.tree.TreeModel;
import javax.swing.tree.TreeNode;
import javax.swing.tree.TreePath;
public class TestTreeHyperlinks {
private final class HyperlinkMouseListener extends MouseAdapter {
private final JTree tree;
private HyperlinkMouseListener(JTree tree) {
this.tree = tree;
}
@Override
public void mouseExited(MouseEvent e) {
tree.setCursor(Cursor.getDefaultCursor());
}
@Override
public void mouseClicked(MouseEvent e) {
Element h = getHyperlinkElement(e);
if (h != null) {
Object attribute = h.getAttributes().getAttribute(HTML.Tag.A);
if (attribute instanceof AttributeSet) {
AttributeSet set = (AttributeSet) attribute;
String href = (String) set.getAttribute(HTML.Attribute.HREF);
if (href != null) {
try {
Desktop.getDesktop().browse(new URI(href));
} catch (IOException e1) {
e1.printStackTrace();
} catch (URISyntaxException e1) {
e1.printStackTrace();
}
}
}
}
}
@Override
public void mouseMoved(MouseEvent event) {
boolean isHyperlink = isHyperlink(event);
if (isHyperlink) {
tree.setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
} else {
tree.setCursor(Cursor.getDefaultCursor());
}
}
private boolean isHyperlink(MouseEvent event) {
return getHyperlinkElement(event) != null;
}
private Element getHyperlinkElement(MouseEvent event) {
Point p = event.getPoint();
int selRow = tree.getRowForLocation(p.x, p.y);
TreeCellRenderer r = tree.getCellRenderer();
if (selRow != -1 && r != null) {
TreePath path = tree.getPathForRow(selRow);
Object lastPath = path.getLastPathComponent();
Component rComponent = r.getTreeCellRendererComponent(tree, lastPath, tree.isRowSelected(selRow), tree.isExpanded(selRow),
tree.getModel().isLeaf(lastPath), selRow, true);
if (rComponent instanceof JEditorPane) {
Rectangle pathBounds = tree.getPathBounds(path);
JEditorPane editor = (JEditorPane) rComponent;
editor.setBounds(tree.getRowBounds(selRow));
p.translate(-pathBounds.x, -pathBounds.y);
int pos = editor.getUI().viewToModel(editor, p);
if (pos >= 0 && editor.getDocument() instanceof HTMLDocument) {
HTMLDocument hdoc = (HTMLDocument) editor.getDocument();
Element elem = hdoc.getCharacterElement(pos);
if (elem.getAttributes().getAttribute(HTML.Tag.A) != null) {
return elem;
}
}
}
}
return null;
}
}
@SuppressWarnings("serial")
public class MyTreeCellRenderer extends DefaultTreeCellRenderer implements TreeCellRenderer {
private JEditorPane editorPane;
public MyTreeCellRenderer() {
editorPane = new JEditorPane("text/html", null);
}
@Override
public Component getTreeCellRendererComponent(JTree tree, Object value, boolean selected, boolean expanded, boolean leaf, int row,
boolean hasFocus) {
Component c = super.getTreeCellRendererComponent(tree, value, selected, expanded, leaf, row, hasFocus);
if (c instanceof JLabel) {
JLabel label = (JLabel) c;
editorPane.setText(label.getText());
editorPane.setToolTipText(label.getToolTipText());
editorPane.setOpaque(label.isOpaque());
editorPane.setBackground(label.getBackground());
editorPane.setBorder(label.getBorder());
}
return editorPane;
}
}
protected void initUI() {
final JTree tree = new JTree(getTreeModel());
tree.setCellRenderer(new MyTreeCellRenderer());
HyperlinkMouseListener listener = new HyperlinkMouseListener(tree);
tree.addMouseListener(listener);
tree.addMouseMotionListener(listener);
JFrame f = new JFrame(TestTreeHyperlinks.class.getSimpleName());
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(new JScrollPane(tree), BorderLayout.CENTER);
f.pack();
f.setSize(f.getWidth() + 100, f.getHeight() + 100);
f.setVisible(true);
}
private TreeModel getTreeModel() {
return new DefaultTreeModel(
getNodes(new DefaultMutableTreeNode("<html>Root <a href=\"http://www.google.be\">Google</a></html>"), 5));
}
private TreeNode getNodes(DefaultMutableTreeNode parent, int i) {
if (i > 0) {
for (int j = 0; j < 5; j++) {
DefaultMutableTreeNode newChild = new DefaultMutableTreeNode(
"<html>Node "
+ (j + 1)
+ " <a href=\"http://www.stackoverflow.com\">a link to stackoverflow</a></html> and some more text not in an hyperlink");
getNodes(newChild, i - 1);
parent.add(newChild);
}
}
return parent;
}
public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException,
UnsupportedLookAndFeelException {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
new TestTreeHyperlinks().initUI();
}
});
}
}
此代碼有效：
tree_object.addMouseMotionListener(new MouseMotionListener() {
@Override
public void mouseDragged(MouseEvent e) {
}
@Override
public void mouseMoved(MouseEvent e) {
TreePath tp = ((JTree)e.getSource()).getPathForLocation(e.getX(), e.getY());
if(tp != null)
{
((JTree)e.getSource()).setCursor(new Cursor(Cursor.HAND_CURSOR));
}
else
{
((JTree)e.getSource()).setCursor(new Cursor(Cursor.DEFAULT_CURSOR));
}
}
});
如何將鼠標監聽器添加到JTree，以便在將鼠標懸停在節點上時可以更改光標（到手形光標）？
[英]How to add a mouse listener to a JTree so that I can change the cursor (to a hand cursor) when hovering over a node?
我們如何使用 select 和 hover 事件動態更改 jtree 的葉節點的文本？
[英]How can we change the text of leaf node of jtree dynamically withour select and hover event?
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