使用JComboBox Java Swing选择颜色(Pick Color with JComboBox Java Swing)

 我有一个JComboBox，我希望用户选择颜色。 JComboBox只显示颜色，没有任何文字。 我想出了这个解决方案。 请告诉我这是好还是应该避免，为什么。 我是Swing和Java的新手，所以请耐心等待:) 
 
public class ToolBar{
    private MainFrame mainFrame;

    public ToolBar (MainFrame mainFrame) {
        this.mainFrame = mainFrame;
    }

    public JPanel getToolBar(){

        JPanel toolbarPanel = new JPanel(new FlowLayout(FlowLayout.LEADING,2,2));
        toolbarPanel.setPreferredSize(new Dimension(mainFrame.getScreenWidth(),60));
        toolbarPanel.setBorder(BorderFactory.createLineBorder(Color.gray));

        JButton fillButton = new JButton("Fill: ");
        fillButton.setPreferredSize(new Dimension(60,20));
        //fillButton.setBackground(Color.red);
        toolbarPanel.add(fillButton);

        String[] test = {" ", " " , " " , " " , " " , " "};
        JComboBox colorBox = new JComboBox(test);
        colorBox.setMaximumRowCount(5);
        colorBox.setPreferredSize(new Dimension(50,20));
        colorBox.setRenderer(new MyCellRenderer());
        toolbarPanel.add(colorBox);

        return toolbarPanel;
    }
    class MyCellRenderer extends JLabel implements ListCellRenderer {  
         public MyCellRenderer() {  
             setOpaque(true);  
         }  
         public Component getListCellRendererComponent(  
             JList list,  
             Object value,  
             int index,  
             boolean isSelected,  
             boolean cellHasFocus)  
         {  
             setText(value.toString()); 
             switch (index) {
                case 0:  setBackground(Color.white);
                break;
                case 1:  setBackground(Color.red);
                break;
                case 2:  setBackground(Color.blue);
                break;
                case 3:  setBackground(Color.yellow);
                break;
                case 4:  setBackground(Color.green);
                break;
                case 5:  setBackground(Color.gray);
                break;
             }
             return this;  
         }  
    }
}
 
 这很好用。 它在JComboBox中显示不同颜色的空选择元素。 问题是当用户选择颜色时，JComboBox中的选择颜色不会改变。 我应该添加哪些代码行，以便当用户从列表中选择颜色时，JComboBox字段中会显示颜色？ 
 
 我尝试了一些解决方案，但结果是当用户选择JComboBox中的颜色​​选择时总是变为灰色... 
 
 我已经查看了几个类似的问题但我无法弄清楚当选择完成时哪部分代码正在处理JComboBox的颜色变化... 

I have a JComboBox where I want for user to select color. JComboBox is displaying just the colors, without any text. I've come up with this solution. Please advise me if this is good or it should be avoided and why. I am new to Swing and Java in general so please be patient :)
 
public class ToolBar{
    private MainFrame mainFrame;

    public ToolBar (MainFrame mainFrame) {
        this.mainFrame = mainFrame;
    }

    public JPanel getToolBar(){

        JPanel toolbarPanel = new JPanel(new FlowLayout(FlowLayout.LEADING,2,2));
        toolbarPanel.setPreferredSize(new Dimension(mainFrame.getScreenWidth(),60));
        toolbarPanel.setBorder(BorderFactory.createLineBorder(Color.gray));

        JButton fillButton = new JButton("Fill: ");
        fillButton.setPreferredSize(new Dimension(60,20));
        //fillButton.setBackground(Color.red);
        toolbarPanel.add(fillButton);

        String[] test = {" ", " " , " " , " " , " " , " "};
        JComboBox colorBox = new JComboBox(test);
        colorBox.setMaximumRowCount(5);
        colorBox.setPreferredSize(new Dimension(50,20));
        colorBox.setRenderer(new MyCellRenderer());
        toolbarPanel.add(colorBox);

        return toolbarPanel;
    }
    class MyCellRenderer extends JLabel implements ListCellRenderer {  
         public MyCellRenderer() {  
             setOpaque(true);  
         }  
         public Component getListCellRendererComponent(  
             JList list,  
             Object value,  
             int index,  
             boolean isSelected,  
             boolean cellHasFocus)  
         {  
             setText(value.toString()); 
             switch (index) {
                case 0:  setBackground(Color.white);
                break;
                case 1:  setBackground(Color.red);
                break;
                case 2:  setBackground(Color.blue);
                break;
                case 3:  setBackground(Color.yellow);
                break;
                case 4:  setBackground(Color.green);
                break;
                case 5:  setBackground(Color.gray);
                break;
             }
             return this;  
         }  
    }
}
 
This works ok. It is displaying empty selection elements in JComboBox with different colors. Problem is that when user selects color, color of selection in JComboBox does not change. Which lines of code should I add and where so that when user selects the color from a list that color is displayed in JComboBox field?
 
I tried some solutions but result was that when user picks color selection in JComboBox always changes to gray...
 
I've looked through several similar questions but I just can't figure out which part of code is dealing with changing of color of JComboBox when the selection has been done...

原文：https://stackoverflow.com/questions/18830098