java - 不显示对象的动态 JPanel

Question

有人可以看一下我的这部分代码并告诉我为什么它不返回 JPanel 中的对象吗？它肯定进入了循环，因为我尝试在里面打印语句。此 JPanel 对象也被放入 TabbedPane 中只是为了澄清。如果我需要更详细地解释或显示更多代码以找到解决方案，请告诉我。谢谢。

JPanel createTipTailoringPanel(TipCalcModel model)
{

    JPanel content = new JPanel();
    int size = model.getNumOfPeople();
    content.removeAll();
    content.updateUI();
    content.setLayout(new GridLayout(0,4));

    JTextField text[] = new JTextField[size];
    JSlider slider[] = new JSlider[size];
    JLabel label[] = new JLabel[size];
    JLabel cash[] = new JLabel[size];


    if(size == 0)
    {
        return content;
    }
    else
    {
        for(int i=0; i<size; i++)
        {
            text[i] = new JTextField();
            slider[i] = new JSlider();
            label[i] = new JLabel("$");
            cash[i] = new JLabel();
            content.add(text[i]);
            content.add(slider[i]);
            content.add(label[i]);
            content.add(cash[i]);
        }

        return content;
    }


}

这是我的调用方法和我用来传递人数的 actionlistener:

 TipCalcView(TipCalcModel model)
{
    setTitle("Tip Calculator");
    JTabbedPane tabbedPane = new JTabbedPane();
    getContentPane().add(tabbedPane);
    tabbedPane.addTab("Main Menu", createMainPanel());
    tabbedPane.setSelectedIndex(0);
    tabbedPane.addTab("Tip Tailoring", createTipTailoringPanel(model));
    tabbedPane.addTab("Config Panel", createConfigPanel());

}

class GuestsListener implements ActionListener
{
    public void actionPerformed(ActionEvent e)
    {
        int userInput = 0;
        try{
            userInput = m_view.getGuests();
            m_model.setNumOfPeople(userInput);
            m_view.createTipTailoringPanel(m_model);
        }
        catch(NumberFormatException nfex)
        {
            m_view.showError("Bad input: '" + userInput + "'");
        }
    }
}

Answer 1

我怀疑您的问题出在您列出的代码之外。这是一个简化的工作示例:

public static void main(String[] args) {
    JFrame frame = new JFrame();
    DynamicJPanel dynamic = new DynamicJPanel();
    frame.add(dynamic.createTipTailoringPanel(3));
    frame.pack();
    frame.setVisible(true);
}

JPanel createTipTailoringPanel(int size) {
    JPanel content = new JPanel();
    content.setLayout(new GridLayout(0, 4));

    for (int i = 0; i < size; i++) {
        content.add(new JTextField());
        content.add(new JSlider());
        content.add(new JLabel("$"));
        content.add(new JLabel());
    }

    return content;
}