如何在 Java 中自动调整 JTree 的大小
要在 Java 中自动调整 JTree 的大小,请使用 setVisibleRowCount() 方法。首先,在树中创建一个节点 -
DefaultMutableTreeNode node = new DefaultMutableTreeNode("Project");现在,向上面创建的节点添加节点 -
DefaultMutableTreeNode node1 = new DefaultMutableTreeNode("App");
DefaultMutableTreeNode node2 = new DefaultMutableTreeNode("Website");
DefaultMutableTreeNode node3 = new DefaultMutableTreeNode("WebApp");
node.add(node1);
node.add(node2);
node.add(node3);现在,创建更多节点,并将它们设置为我们上面创建的节点的子节点 -
DefaultMutableTreeNode one = new DefaultMutableTreeNode("Learning website");
DefaultMutableTreeNode two = new DefaultMutableTreeNode("Business website");
DefaultMutableTreeNode three = new DefaultMutableTreeNode("News publishing website");
DefaultMutableTreeNode four = new DefaultMutableTreeNode("Android app");
DefaultMutableTreeNode five = new DefaultMutableTreeNode("iOS app");
DefaultMutableTreeNode six = new DefaultMutableTreeNode("Editor WebApp");
node1.add(one);
node1.add(two);
node1.add(three);
node2.add(four);
node2.add(five);
node3.add(six);现在,创建一个 JTree 并设置其中的根节点 -
JTree tree = new JTree(node);
以下内容将显示滚动条,并且仅允许 8 行可见 -
tree.setVisibleRowCount(8); JOptionPane.showMessageDialog(null, new JScrollPane(tree));
以下是如何自动调整 JTree 大小的示例 -
示例
package my;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;
public class SwingDemo {
public static void main(String[] args) throws Exception {
JFrame frame = new JFrame("Demo");
DefaultMutableTreeNode node = new DefaultMutableTreeNode("Project");
DefaultMutableTreeNode node1 = new DefaultMutableTreeNode("App");
DefaultMutableTreeNode node2 = new DefaultMutableTreeNode("Website");
DefaultMutableTreeNode node3 = new DefaultMutableTreeNode("WebApp");
node.add(node1);
node.add(node2);
node.add(node3);
DefaultMutableTreeNode one = new DefaultMutableTreeNode("Learning website");
DefaultMutableTreeNode two = new DefaultMutableTreeNode("Business website");
DefaultMutableTreeNode three = new DefaultMutableTreeNode("News publishing website");
DefaultMutableTreeNode four = new DefaultMutableTreeNode("Android app");
DefaultMutableTreeNode five = new DefaultMutableTreeNode("iOS app");
DefaultMutableTreeNode six = new DefaultMutableTreeNode("Editor WebApp");
node1.add(one);
node1.add(two);
node1.add(three);
node2.add(four);
node2.add(five);
node3.add(six);
JTree tree = new JTree(node);
frame.add(tree);
tree.setVisibleRowCount(8);
JOptionPane.showMessageDialog(null, new JScrollPane(tree));
}
}输出

现在,如果单击每个节点,则会出现子节点。在扩展可见行数后,会出现一个滚动条来调整 TREE 的大小 -

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