Java Swing編程之仿js樹狀摺疊菜單

標籤：

最近要完成一個需求：用swing做個樹狀菜單，含二級菜單，點擊一級菜單展開二級菜單，且二級菜單數目超過預覽視圖會出現捲軸。由於swing研究的少，花了不少精力！

先看下測試：

收合圖：

展開圖：

完整源碼：

  1 package com.xuwei.test2;  2   3 import java.awt.BorderLayout;  4 import java.awt.Color;  5 import java.awt.GridLayout;  6 import java.awt.event.ActionEvent;  7 import java.awt.event.ActionListener;  8   9 import javax.swing.JButton; 10 import javax.swing.JFrame; 11 import javax.swing.JPanel; 12 import javax.swing.JScrollPane; 13  14  15 public class TestFrm4 extends JFrame{ 16     private JButton btn1,btn2,btn3,btn4,btn5; 17     private JPanel pNorth,pSouth,subMenuContainer; 18     private JScrollPane pCenter; 19     private JButton[] btn = null; 20     private static boolean expand=false; 21      22     public TestFrm4(){ 23         btn1=new JButton("Grade1 menu1"); 24         btn1.setBackground(Color.CYAN); 25         btn2=new JButton("Grade1 menu2"); 26         btn2.setBackground(Color.CYAN); 27         btn3=new JButton("Grade1 menu3"); 28         btn3.setBackground(Color.CYAN); 29         btn3.addActionListener(new ActionHandler()); 30          31         btn4=new JButton("Grade1 menu4"); 32         btn4.setBackground(Color.CYAN); 33         btn5=new JButton("Grade1 menu5"); 34         btn5.setBackground(Color.CYAN); 35         pNorth=new JPanel(); 36         pNorth.setLayout(new GridLayout(3,1)); 37         pSouth=new JPanel(); 38         pSouth.setLayout(new GridLayout(2,1)); 39         subMenuContainer=new JPanel(); 40         subMenuContainer.setLayout(new GridLayout(25,1)); 41       42         btn=new JButton[25];         43         for(int i=0;i<btn.length;i++){ 44             btn[i]=new JButton("[菜單"+i+"]"); 45             btn[i].setBackground(Color.WHITE); 46         } 47          48         this.setLayout(new BorderLayout()); 49          50         pNorth.add(btn1); pNorth.add(btn2); pNorth.add(btn3);  51         for(int i=0;i<btn.length;i++){ 52             subMenuContainer.add(btn[i]); 53         } 54         pCenter=new JScrollPane(subMenuContainer); 55          56         pSouth.add(btn4);pSouth.add(btn5); 57         this.add(pNorth,"North"); 58         this.add(pCenter,"Center"); 59         this.add(pSouth,"South"); 60         61         this.setVisible(true); 62         this.setSize(500,600); 63         this.setResizable(false); 64         this.setLocationRelativeTo(null); 65         this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 66          67     } 68      69      70      71     private class ActionHandler implements ActionListener{ 72  73         @Override 74         public void actionPerformed(ActionEvent e) { 75             if(btn3==e.getSource()){ 76                 if(expand){//摺疊 77                    pNorth.setLayout(new GridLayout(3,1)); 78                    pNorth.remove(btn4);pNorth.remove(btn5); 79                    pSouth.add(btn4);pSouth.add(btn5); 80                    for(int i=0;i<btn.length;i++){ 81                        subMenuContainer.add(btn[i]); 82                    }      83                    validate(); 84                    getContentPane().repaint(); 85                    expand=false; 86                 }else{//展開 87                     for(int i=0;i<btn.length;i++){ 88                         subMenuContainer.remove(btn[i]); 89                     } 90                     pSouth.removeAll(); 91                     pNorth.setLayout(new GridLayout(5,1)); 92                     pNorth.add(btn4); 93                     pNorth.add(btn5); 94                     pNorth.repaint(); 95                     pCenter.repaint(); 96                     pSouth.repaint(); 97                     validate(); 98                     getContentPane().repaint(); 99                     expand=true;100                 }101             }102         }103         104     }105     106     public static void main(String[] args) {107        108         new TestFrm4();109     }110 111 }

這裡頻繁添加刪除群組件需要及時重新整理介面，swing有幾個方法要反覆調用：

repaint(),validate(),invalidate(),doLayout().

之前我由於沒調用validate()導致介面重新整理出現很多問題！

swing要仔細研究發現東西也不少！

 

Java Swing編程之仿js樹狀摺疊菜單