KeyListener和keyPressed

Question

我在試圖構建屏幕鍵盤，我需要一點幫助。 這個想法：來自外部源的文本複製（複製和粘貼）將用於學習觸摸打字。
當您鍵入正確的字符，字符被突出顯示在JTextArea中，以綠色，而如果你不正確的字符按鈕的顏色會變爲綠色， ，所以按鈕將顏色更改爲紅色

當我按下我的電腦鍵盤時，屏幕鍵盤上的按鈕不會將其背景更改爲綠色。

public class Box extends JFrame { 
JFrame frame = new JFrame("Box Value & Area"); 
GridLayout Form_Grig = new GridLayout(3,0); 
GridLayout Panel_Grid = new GridLayout(1,18); 
JPanel ans = new JPanel(new GridLayout(1,2)); 
final JLabel label =new JLabel("Points : "); 
final JLabel label2 = new JLabel("answer "); 
final JLabel label3 = new JLabel("length : "); 
final JLabel label4 = new JLabel("Volume"); 
public int index=0; 
public int counter=0; 
public int press_count=-1; 
JPanel panel = new JPanel(); 
private JPanel parent = new JPanel(new GridLayout(0, 1)); 
final JTextArea text1 = new JTextArea();  
private JButton[][] button; 
private JPanel[] Panel = new JPanel[6]; 
public JButton start = new JButton("Start game"); 
private static final String[][] key = { 
     {"Esc", "F1", "F2", "F3", "F4", "F5", "F6", "F7", "F8", "F9", "F10", "F11", "F12", "Num", "Insert", "Delete", "Pause"}, 
     {"~\n`", "1", "2", "3", "4", "5","6", "7", "8", "9", "0", "-", "=", "Backspace "}, 
     {" Tab ", "Q", "W", "E", "R", "T", "Y", "U", "I", "O", "P", "{", "}", "|"}, 
     {"Caps Lock","A", "S", "D", "F", "G", "H", "J", "K", "L", ";", "'", " Enter  "}, 
     {"  Shift  ", "Z", "X", "C", "V", "B","N", "M", "<", ">", "?", "Shift"}, 
     {"Ctrl", "Fn", "Alt", "    Space         ", "Alt","Ctrl"}};  
public Box(){     
      frame.setLayout(Form_Grig);          
      frame.add(text1); 
      ans.add(label); 
      ans.add(label2); 
      button = new JButton[20][20]; 
      for (int row = 0; row < key.length; row++) {          
       Panel[row] = new JPanel();      
        for (int column = 0; column < key[row].length; column++) { 

         button[row][column] = new JButton(key[row][column]); 
         button[row][column].putClientProperty("column", column); 
         button[row][column].putClientProperty("row", row); 
         button[row][column].putClientProperty("key", key[row][column]); 
         button[row][column].addActionListener(new MyActionListener());                 
         Panel[row].add(button[row][column]); 
        } 
        parent.add(Panel[row]); 
      } 
      frame.add(ans);            
      frame.add(parent);           
      frame.pack(); 
      frame.setResizable(false); 
      frame.setVisible(true);           
      Font font = new Font("Verdana", Font.BOLD, 56); 
      label2.setFont(font); 
      label2.setForeground(Color.gray); 
      label.setFont(font); 
      label.setForeground(Color.gray); 
} 
public class MyActionListener implements ActionListener { 
    String te = text1.getText();   
    @Override 
    public void actionPerformed(ActionEvent e) {  
    final JButton btn =(JButton) e.getSource(); 
     text1.addKeyListener(new KeyListener(){ 
      @Override 
      public void keyPressed(KeyEvent e) { 
       if (!text1.getText().equals("")){ 

        text1.setEditable(false); 
       } 
       btn.setBackground(Color.green); 
       System.out.println("this :"+ btn.getName()); 
      } 
      @Override 
      public void keyReleased(KeyEvent e) { //dsd       
      } 
      @Override 
      public void keyTyped(KeyEvent e) {//sdsd 
       // TODO Auto-generated method stub    
      }    

     });          
     String te = text1.getText(); 
     String Size = null; 

      if(press_count >= te.length() ){ 
       JOptionPane.showMessageDialog(null, "from "+te.length() +" characters you guess "+index);    
      } 
      press_count++; 
      Size = Integer.toString(te.length());//adad 
      if (index==0) 
       counter=te.length();  
     label2.setText(Size); //setText  
     String bbb = (String) btn.getClientProperty("key") ; 


      if(bbb.equals(String.valueOf(te.charAt(index)))){ 

       btn.setBackground(Color.green);        
       label2.setText(Integer.toString(counter)); 
      } 
      else{ 

       btn.setBackground(Color.red);//setting background 
       counter--; 
       label2.setText(Integer.toString(counter)); 

      } 
      index++;// 
    } 

} 

爲什麼當我按下屏幕鍵盤不改變它的背景色在pc上的按鈕，按鈕？

Answer 1

「爲什麼當我按下PC按鈕，屏幕鍵盤上的按鈕不改變其背景色」

他們做出改變，而是看你的邏輯，：

只有在文本區域按下某個鍵時，它纔會改變顏色。這意味着您需要重新回到文本區域並鍵入內容。

您還將在文本區域添加多個KeyListener，每按一次按鈕。我不認爲這就是你想要做的。

其實。對於文本組件，您不應該使用全部爲的KeyListener。應通過DocumentListener收聽文本組件基礎文檔中的更改。 DocumentListener應只添加一次到文本區域，ActionListener之外。原因是一個組件可能有多個註冊的監聽器，即使它是同一個監聽器（就像你正在做的那樣）。會發生什麼是每個偵聽器回調都被放入一個隊列中。所以如果你按了10個按鈕，那麼文本區域將有10個監聽器回調，每次你按下一個鍵時，回調將被調用10次。

你應該多看一些關於How To Use DocumentListner

還在爲色彩到按鈕的變化的印刷機，你可能想看看this question。