如何在 Java 中實現 JTree 的各個節點的滑鼠右鍵點選?\n
JTree 是JComponent 類的子類,可用於透過向節點新增節點 並保留父節點和子節點的概念來顯示具有層次結構屬性的資料。樹中的每個元素都成為一個節點。這些節點是可展開和可摺疊的。我們可以使用MouseAdapter 類的mouseReleased()方法實現 JTree 中每個節點的滑鼠右鍵單擊,並且需要呼叫JPopupMenu 類的show()方法以在樹節點上顯示彈出選單。
示例
import java.awt.*; import java.awt.event.*; import javax.swing.*; import javax.swing.tree.*; public class JTreeRightClickTest extends JFrame { public JTreeRightClickTest() { DefaultMutableTreeNode root = createNodes(); JTree tree = new JTree(root); final TreePopup treePopup = new TreePopup(tree); tree.addMouseListener(new MouseAdapter() { public void mouseReleased(MouseEvent e) { if(e.isPopupTrigger()) { treePopup.show(e.getComponent(), e.getX(), e.getY()); } } }); add(new JScrollPane(tree), BorderLayout.NORTH); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setSize(400, 300); setLocationRelativeTo(null); setVisible(true); } public static DefaultMutableTreeNode createNodes() { DefaultMutableTreeNode root = new DefaultMutableTreeNode("Technology"); DefaultMutableTreeNode node1 = new DefaultMutableTreeNode("Java"); DefaultMutableTreeNode node2 = new DefaultMutableTreeNode("Python"); DefaultMutableTreeNode node3 = new DefaultMutableTreeNode("Selenium"); node1.add(new DefaultMutableTreeNode("Programming Language")); node2.add(new DefaultMutableTreeNode("Programming Language")); node3.add(new DefaultMutableTreeNode("Testing Framework")); root.add(node1); root.add(node2); root.add(node3); return root; } public static void main(String args[]) { new JTreeRightClickTest(); } } class TreePopup extends JPopupMenu { public TreePopup(JTree tree) { JMenuItem delete = new JMenuItem("Delete"); JMenuItem add = new JMenuItem("Add"); delete.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent ae) { System.out.println("Delete child"); } }); add.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent ae) { System.out.println("Add child"); } }); add(delete); add(new JSeparator()); add(add); } }
輸出
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