如何在 Java 中自动调整 JTree 的大小
java 8object oriented programmingprogramming
要自动调整 JTree 的大小，请使用 Java 中的 setVisibleRowCount() 方法。首先，在树中创建一个节点 −
DefaultMutableTreeNode node = new DefaultMutableTreeNode("Project");
现在，将节点添加到上面创建的节点 −
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 并在其中设置根节点 −
JTree tree = new JTree(node);
以下将显示滚动条，并且只允许 8 行可见 −
tree.setVisibleRowCount(8); JOptionPane.showMessageDialog(null, new JScrollPane(tree));
以下是自动调整 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，当您单击每个节点时，子节点将显示出来。在扩展可见行数时，将出现一个 ScrollBar 来调整 TREE 的大小−
