Java中,以编程方式选择和扩展JTree中的多个节点的过程可以通过以下步骤实现:
下面是一个示例代码,它遍历JTree树并选择节点:
import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.TreeCellRenderer;
import javax.swing.tree.TreeModel;
import java.awt.Component;
import java.util.Objects;
public class TreeSelection {
public static void main(String[] args) {
JTree tree = new JTree();
tree.setModel(createModel());
TreeCellRenderer renderer = new MyRenderer();
tree.setCellRenderer(renderer);
// Select the second node in the tree
int node = 1;
tree.getSelectionModel().setSelectionPath(new TreePath(tree.getModel().getRoot(), node));
// Get the selected node
Object selectedNode = tree.getSelectionModel().getSelectedItem();
// Print the selected node
System.out.println("Selected node: " + selectedNode);
}
public static DefaultTreeModel createModel() {
DefaultMutableTreeNode root = new DefaultMutableTreeNode("root");
root.add(new DefaultMutableTreeNode("node1"));
root.add(new DefaultMutableTreeNode("node2"));
root.add(new DefaultMutableTreeNode("node3"));
DefaultTreeModel model = new DefaultTreeModel(root);
return model;
}
public static class MyRenderer implements TreeCellRenderer {
public Component getTreeCellRendererComponent(
JTree tree,
Object value,
boolean selected,
boolean expanded,
boolean leaf,
int row,
boolean hasFocus
) {
String stringValue = Objects.toString(value, "");
setText(stringValue);
if (selected) {
setBackground(new java.awt.Color(255, 255, 255));
setBackground(tree.getSelectionBackground());
} else {
setBackground(tree.getBackground());
}
return this;
}
}
}
该示例代码定义了一个MyRenderer
类,它实现了TreeCellRenderer
接口,并使用getTreeCellRendererComponent()
方法来返回一个自定义的树单元格。在getTreeCellRendererComponent()
方法中,我们可以设置各种属性,例如单元格文本、单元格背景色和选中状态等。
在该示例代码中,我们使用MyRenderer
类来渲染树单元格,并在树单元格中选择时显示背景色。
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