Java 新手需要友好的帮助建议，在文本字段中阅读以使按钮出现/更改

Question

首先，我今晚才刚刚开始用 Java 编码，所以如果我看起来像个新手并且我的代码很糟糕，我深表歉意，我是一个新手。基本上，当在单独的 j 框架上的文本字段中输入特定数字时，我希望图像改变颜色。因此，汽车在装载时显示为蓝色，如果按下 1，汽车就会移动并改变颜色。我的问题是我似乎无法访问文本变量来操作它。任何帮助将不胜感激，谢谢 x

public class ImageBackground extends JFrame 
{

public static void main(String[] args) throws Exception
{
    JFrame F = new JFrame("CrossRoads Simulation");
    TextDemo textDemo = new TextDemo();  

    try
    {
        F.setContentPane(new JLabel(new ImageIcon(ImageIO.read(new       File("C:/Users/Stacy/workspace/Test/crossRoadsBackground.png")))));

}
    catch(IOException e)
    {
        System.out.println("Image doesnt exist");
    }

    F.setResizable(false);
    F.pack();
    F.setVisible(true);


    JButton button = new JButton(new ImageIcon("C:/Users/Stacy/workspace /Test/CarBlueOne.png"));
     button.setSize(new Dimension(50, 50));
     button.setLocation(130, 210);

button.setOpaque(false);
button.setContentAreaFilled(false);
button.setBorderPainted(false);


     F.add(button);
     textDemo.createAndShowGUI();

    //Make sure the new text is visible, even if there
    //was a selection in the text area.
     textDemo.textArea.setCaretPosition(textDemo.textArea.getDocument().getLength(    ));       
    }
 }

TextDemo.java

public class TextDemo extends JPanel implements ActionListener {
public JTextField textField;
public JTextArea textArea;
public final static String newline = "\n";    
JFrame F = new JFrame("CrossRoads Simulation");
ImageBackground imageBackground = new ImageBackground(); 
 public TextDemo() {    
    super(new GridBagLayout());
    textField = new JTextField(20);
    textField.addActionListener(this);    
    textArea = new JTextArea(5, 20);
    textArea.setEditable(false);
    JScrollPane scrollPane = new JScrollPane(textArea);

    //Add Components to this panel.
    GridBagConstraints c = new GridBagConstraints();
    c.gridwidth = GridBagConstraints.REMAINDER;

    c.fill = GridBagConstraints.HORIZONTAL;
    add(textField, c);

    c.fill = GridBagConstraints.BOTH;
    c.weightx = 1.0;
    c.weighty = 1.0;
    add(scrollPane, c); 
}

protected static void createAndShowGUI() {
    //Create and set up the window.
    JFrame frame = new JFrame("TextDemo");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    //Add contents to the window.
    frame.add(new TextDemo());

    //Display the window.
    frame.pack();
    frame.setVisible(true);          
}
public void actionPerformed(ActionEvent evt) {

    String text = textField.getText();
    int input = Integer.parseInt(text);

if (input == 1)
{

    JButton button = new JButton(new ImageIcon("C:/Users/Stacy/workspace /Test/CarRedOne.png"));
     button.setSize(new Dimension(50, 50));
     button.setLocation(170, 210);
}
textArea.append(text + newline);
textField.selectAll(); 

}     
}

Answer 1

您没有任何代码将 TextDemo 中的文本变量公开给其他类。您应该从 TextField 变量中读取/修改文本。它应该类似于:

公共(public)字符串 getText() { 返回textField.getText();}

公共(public)无效setText(字符串文本){ textField.setText(文本);}