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 -

更新于:2019 年 7 月 30 日

240 次浏览

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