使用TreeMap填充組合框

Question

我正在研究一個項目，該項目需要我從文本文件中將顏色和十六進制代碼讀取到地圖中。我創建了一個TreeMap，並在屏幕上正確存儲和打印，但我無法弄清楚如何讓它將數據發送到組合框。這裏是我的代碼迄今...

public class Project extends JFrame{ 

    JComboBox CBColor = new JComboBox(new String[] 
    {"", "AQUA", "BLACK", "BLUE", "BROWN", "FUCHSIA", "GRAY", 
    "GREEN", "INDIGO", "LIME", "MAROON", "NAVY", "ORANGE", 
    "PINK", "PURPLE", "RED", "SIENNA", "TAN", "TEAL", "WHITE", "YELLOW"}); 
    JTextArea TAText = new JTextArea(5, 25); 
    JButton BApply = new JButton("Apply"); 
    JButton BExit = new JButton("Exit"); 

    public Project() { 
     JPanel SelectionPanel = new JPanel(new BorderLayout()); 
     SelectionPanel.add(CBColor, BorderLayout.NORTH); 
     SelectionPanel.add(TAText, BorderLayout.CENTER); 
     JPanel ApplyPanel = new JPanel(new FlowLayout(FlowLayout.CENTER, 10, 10)); 
     ApplyPanel.add(BApply); 
     ApplyPanel.add(BExit); 
     add(SelectionPanel, BorderLayout.NORTH); 
     add(ApplyPanel, BorderLayout.SOUTH); 
     BApply.addActionListener(new ButtonListener()); 
     BExit.addActionListener(new ExitButtonListener()); 
    } 

    private class ButtonListener implements ActionListener { 
      public void actionPerformed(ActionEvent e) { 
       String BGColor = ""; 
       if (CBColor.getSelectedItem() == "AQUA") 
        BGColor = "#00FFFF"; 
       else if (CBColor.getSelectedItem() == "BLACK") 
        BGColor = "#000000"; 
       else if (CBColor.getSelectedItem() == "BLUE") 
        BGColor = "#0000FF"; 
       else if (CBColor.getSelectedItem() == "BROWN") 
        BGColor = "#A52A2A"; 
       else if (CBColor.getSelectedItem() == "FUCHSIA") 
        BGColor = "#FF00FF"; 
       else if (CBColor.getSelectedItem() == "GRAY") 
        BGColor = "#BEBEBE"; 
       else if (CBColor.getSelectedItem() == "GREEN") 
        BGColor = "#008000"; 
       else if (CBColor.getSelectedItem() == "INDIGO") 
        BGColor = "#4B0082"; 
       else if (CBColor.getSelectedItem() == "LIME") 
        BGColor = "#00FF00"; 
       else if (CBColor.getSelectedItem() == "MAROON") 
        BGColor = "#800000"; 
       else if (CBColor.getSelectedItem() == "NAVY") 
        BGColor = "#000080"; 
       else if (CBColor.getSelectedItem() == "ORANGE") 
        BGColor = "#FFA500"; 
       else if (CBColor.getSelectedItem() == "PINK") 
        BGColor = "#FFC0CB"; 
       else if (CBColor.getSelectedItem() == "PURPLE") 
        BGColor = "#800080"; 
       else if (CBColor.getSelectedItem() == "RED") 
        BGColor = "#FF0000"; 
       else if (CBColor.getSelectedItem() == "SIENNA") 
        BGColor = "#A0522D"; 
       else if (CBColor.getSelectedItem() == "TAN") 
        BGColor = "#D2B48C"; 
       else if (CBColor.getSelectedItem() == "TEAL") 
        BGColor = "#008080"; 
       else if (CBColor.getSelectedItem() == "WHITE") 
        BGColor = "#FFFFFF"; 
       else if (CBColor.getSelectedItem() == "YELLOW") 
        BGColor = "#FFFF00"; 
       TAText.setBackground(Color.decode(BGColor)); 
      } 
    } 

    private class ExitButtonListener implements ActionListener { 
      public void actionPerformed(ActionEvent e) { 
      System.exit(0); 
      } 
    } 

    public static void main(String[] args) throws Exception { 

     Map<String, String> ColorsHex = new TreeMap<String, String>(); 

     BufferedReader input = new BufferedReader(new FileReader("colors.txt")); 
     String line = ""; 
     while ((line = input.readLine()) != null) { 
      String parts[] = line.split(", "); 
      ColorsHex.put(parts[0], parts[1]); 
     } 
     input.close();   
     System.out.println(ColorsHex); 
     System.out.print(ColorsHex.keySet()); 
     System.out.print(ColorsHex.get("RED")); 


     Project frame = new Project(); 
     frame.setTitle("Colors"); 
     frame.setLocationRelativeTo(null); 
     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     frame.pack(); 
     frame.setVisible(true); 



    } 


} 

這編譯和運行，但我試圖讓組合框讀進口而不是進入他們的價值觀，和聽衆讀取元素，而不是進入他們。

Answer 1

JComboBox沒有一個構造函數需要Set。您將不得不使用available constructors之一。

更新：

一種解決方案是使用默認的構造函數JComboBox()最初，調用load從文件加載的顏色，然後設置爲JComboBox型號：

protected void loadColors() throws IOException { 
    Map<String, String> colorsHexMap = new TreeMap<String, String>(); 
    BufferedReader input = new BufferedReader(new FileReader("colors.txt")); 
    ... 

    Set<String> keySet = colorsHexMap.keySet(); 
    String[] keyArray = keySet.toArray(new String[keySet.size()]); 
    ComboBoxModel<String> model = new DefaultComboBoxModel<>(keyArray); 
    CBColor.setModel(model); 
} 

此外，如果您將TreeMap設爲類成員變量，則可以將您的十六進制顏色選擇簡化爲2行：

String bgColor = colorsHexMap.get(CBColor.getSelectedItem()); 
TAText.setBackground(Color.decode(bgColor));