Swing新增垂直捲動條範例

2019-10-16 22:05:01

下面的範例展示了如何在Java Swing應用程式中的面板上始終顯示帶有垂直條的捲動窗格。

使用以下API -

  • JScrollPane(Component view) - 在元件上建立scrollPane
  • JScrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS)- 始終顯示垂直條。

範例

package com.yiibai.swingdemo;

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("Swing新增垂直捲動條範例");
      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);  
   }   
}

執行上面範例程式碼,得到以下結果: