Swing 示例 - 添加垂直滚动条

以下示例展示了如何在 Java Swing 应用程序中的面板上始终显示带有垂直条的滚动窗格。

我们使用以下 API。

• JScrollPane(组件视图) − 在组件上创建滚动窗格。

• JScrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_​​ALWAYS) − 始终显示垂直条。

示例

import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
 
public class SwingTester {
   private JFrame mainFrame;
   private JLabel headerLabel;
   private JLabel statusLabel;
   private JPanel controlPanel;
   
   public SwingTester(){
      prepareGUI();
   }
   public static void main(String[] args){
      SwingTester  swingControlDemo = new SwingTester();      
      swingControlDemo.showScrollPaneDemo();
   }
   private void prepareGUI(){
      mainFrame = new JFrame("Java Swing Examples");
      mainFrame.setSize(400,400);
      mainFrame.setLayout(new GridLayout(3, 1));
      
      mainFrame.addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent windowEvent){
            System.exit(0);
         }        
      });    
      headerLabel = new JLabel("", JLabel.CENTER);        
      statusLabel = new JLabel("",JLabel.CENTER);    
      statusLabel.setSize(350,100);

      controlPanel = new JPanel();
      controlPanel.setLayout(new FlowLayout());

      mainFrame.add(headerLabel);
      mainFrame.add(controlPanel);
      mainFrame.add(statusLabel);
      mainFrame.setVisible(true);  
   }
   
   private JTextArea outputTextArea;
   
   private void showScrollPaneDemo(){
      headerLabel.setText("Control in action: ScrollPane");
      outputTextArea = new JTextArea("",5,20);
      JScrollPane scrollPane = new JScrollPane(outputTextArea);    
      scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
      controlPanel.add(scrollPane);
      mainFrame.setVisible(true);  
   }   
}

swingexamples_scroll_panes.html