Question

我的这个嵌套类有问题。由于某些原因，我无法在构造函数中将我的JComponents添加到我的面板中。它给出了错误

The method of add(JComponent, String) is undefined for the HomePanel.inputFrame

HomePanel是外部类，而inputFrame是我的内部类。我的方法返回JComponents，我可以将它添加到我的外部类，但我的内部类只是不允许它所以我决定只使用add.(enterButton(), BorderLayout.SOUTH)没有给出任何错误但是当我尝试使用mainWindow类中的这个内部类，它说

The method add(JComponent) in the type container is not applicable for the arguments (HomePanel.inputFrame)

但问题是我可以使用mainWindow类的外部类，这使得它出了什么问题令人困惑。是因为它是内部阶级还是我的命令错了？

mainWindow类

public class mainWindow extends JFrame{
    CardLayout cl = new CardLayout();
    private JFrame mainPage = new JFrame("Food Expiry");
    private JPanel mainPanel = new JPanel(cl);
    private static final String homePage = "HomePage";
    private static final String expiryDateEntry = "Expiry Date Entry";
    private JPanel card1 = new JPanel();
    public JPanel card2 = new JPanel();
    HomePanel getGui = new HomePanel();
    HomePanel.inputFrame nextPane = getGui.new inputFrame();
    CardLayout cardLayout = (CardLayout) mainPanel.getLayout();
    public mainWindow(){
       mainPage.setSize(500, 300);
       mainPage.setLocationRelativeTo(null);
       mainPage.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
       mainPage.add(mainPanel);
       mainPage.setVisible(true);
    }
    protected void mainPanel(){
        card1.add(getGui);
    }
    protected void getInput(){
        card2.add(nextPane);
    }
}

HomePanel

public class HomePanel extends JPanel{
private JButton inputButton, storeButton;
private JLabel label, itemLabel;
private JPanel textAreaPanel, buttonPanel, labelPanel;
private JTextField itemField, itemCategory, expiryDate;


public HomePanel(){
    setLayout(new BorderLayout());
    this.add(getLabelPanel("Home"), BorderLayout.NORTH);
    this.add(getButtonPanel(), BorderLayout.CENTER);
}
protected JComponent getButtonPanel(){
    //add some buttons to a buttonPanel
    return buttonPanel;
}
protected JComponent getLabelPanel(String topText){
    //labelPanel
    return labelPanel;
}

class inputFrame {
    private JLabel categoryLabel, expiryLabel;
    private JButton enter, back;


    protected JComponent getInputFrame(){
        textAreaPanel = new JPanel();
        textAreaPanel.setLayout(new BoxLayout(textAreaPanel, 
        BoxLayout.Y_AXIS));
        itemLabel = new JLabel("Item Name: ");
        itemField = new JTextField(15);
        textAreaPanel.add(itemLabel);
        textAreaPanel.add(itemField);

        categoryLabel = new JLabel("Category Name: ");
        itemCategory = new JTextField(33);
        textAreaPanel.add(categoryLabel);
        textAreaPanel.add(itemCategory);

        expiryLabel = new JLabel("Expiry Date: ");
        expiryDate = new JTextField(33);
        textAreaPanel.add(expiryLabel);
        textAreaPanel.add(expiryDate);

        return textAreaPanel;
    }
    protected JComponent enterButton(){
        buttonPanel = new JPanel();
        enter = new JButton("Enter");
        back = new JButton("Back");
        enter.addActionListener(new getInput());
        back.addActionListener(new previousFrame());
        buttonPanel.add(back);
        buttonPanel.add(enter);
        return buttonPanel;
    }
    public inputFrame(){
        setLayout(new BorderLayout());
        add(getLabelPanel("Expiry Date Entry"),BorderLayout.NORTH);
        add(getInputFrame(), BorderLayout.CENTER);
        add(enterButton(), BorderLayout.SOUTH);
    }

    }

我无法在此问题上找到任何重复项，如果有人能够找到任何副本，请在评论中将其链接或回答。谢谢。

Answer 1

所以，基于......

public class HomePanel extends JPanel{
    //...
    class inputFrame {
        //...
  }
}

inputFrame从Object扩展（默认情况下），使其与Container#add兼容，Component期望某些类从inputFrame扩展。

根据当前的实现，HomePanel实际上正在修改实例化public class HomePanel extends JPanel{ //... class inputFrame extends JPanel { //... } }实例的状态，而不是向自身添加组件

像...一样的东西。

docker run -d -p 9001:8081 --name nexus -v /Users/user.name/dockerVolume/nexus:/nexus-data sonatype/nexus3

应该缓解最紧迫的问题

无法使用方法向构造函数

1 个答案: