java - 按下按钮添加新字段

Question

我正在 NetBeans 中创建一个程序，用户可以在其中创建自己的 CSV 文件。我做了一个GUI。当我按下按钮时，我希望一个新的 JLabel 和一个新的 JTextField 出现在现有的下方，与按下按钮的次数一样多。我怎么做？

Answer 1

我做了类似的事情，我正在使用带有GroupLayout的JPanel来解决这个问题，这就是我的代码：

编辑 - 你的问题引起了我的兴趣，我已经根据你的需要改变了我的代码（当然只是基本的，你必须改进它）

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全局变量

private GroupLayout m_layout;
private SequentialGroup m_verticalSg;
private ArrayList<Component> m_labelList;
private ArrayList<Component> m_textFieldList;
private ParallelGroup m_horizontalPgLabels;
private ParallelGroup m_horizontalPgTextfields;

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方法 createLayout()

为您的面板创建布局，其中应包含标签和文本字段组件

private void createLayout()
{
   m_layout = new GroupLayout(YOUR_PANEL);
   YOUR_PANEL.setLayout(m_layout);

   //This SequentialGroup is used for the VerticalGroup
   m_verticalSg = m_layout.createSequentialGroup();
   m_verticalSg.addContainerGap();

   //Two ParallelGroups are used. One for all labels and the other one for all textfields
   m_horizontalPgLabels = m_layout.createParallelGroup(GroupLayout.Alignment.LEADING);
   m_horizontalPgTextfields = m_layout.createParallelGroup(GroupLayout.Alignment.LEADING);

   //These component lists are used for linkSize() -> Equalize components width
   m_labelList = new ArrayList<>();
   m_textFieldList = new ArrayList<>();

   m_layout.setHorizontalGroup(m_layout.createParallelGroup()
                    .addGroup(m_layout.createSequentialGroup()
                    .addContainerGap()
                    .addGroup(m_horizontalPgLabels)
                    .addPreferredGap(LayoutStyle.ComponentPlacement.RELATED) //Create gap between horizontal groups
                    .addGroup(m_horizontalPgTextfields)
                    .addContainerGap()));

   m_layout.setVerticalGroup(m_layout.createParallelGroup().addGroup(m_verticalSg.addContainerGap()));
}

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方法 addNewRow()

从您的按钮单击事件中调用此方法

private void addNewRow()
{
   if(m_layout == null)
      createLayout();

   Dimension dimLabel = new Dimension(100, 15);
   Dimension dimTextfield = new Dimension(200, 20);

   //Create a new label
   JLabel lbl = new JLabel();
   lbl.setText("Your text");
   lbl.setIcon(null/*Your icon*/);
   lbl.setSize(dimLabel);
   lbl.setPreferredSize(dimLabel);

   //Create a new textfield
   JTextField txtField = new JTextField();
   txtField.setSize(dimTextfield);
   txtField.setPreferredSize(dimTextfield);

   //Add components to arrays and increase index
   m_labelList.add(lbl);
   m_textFieldList.add(txtField);

   //Create new ParallelGroup for the vertical SequentialGroup
   ParallelGroup newVerticalParallelGroup = m_layout.createParallelGroup(GroupLayout.Alignment.LEADING);
   newVerticalParallelGroup.addComponent(lbl);
   newVerticalParallelGroup.addComponent(txtField);
   m_verticalSg.addGroup(newVerticalParallelGroup);
        m_verticalSg.addPreferredGap(LayoutStyle.ComponentPlacement.RELATED);

   //Add the new label to the horizontal label group
   m_horizontalPgLabels.addComponent(lbl, GroupLayout.Alignment.CENTER);
   //Add the new textfield to the horizontal textfield group
   m_horizontalPgTextfields.addComponent(txtField);

   m_layout.linkSize(SwingConstants.HORIZONTAL, m_labelList.toArray(new Component[m_labelList.size()]));
   m_layout.linkSize(SwingConstants.HORIZONTAL, m_textFieldList.toArray(new Component[m_textFieldList.size()]));
}

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最后一步是将ActionListener添加到您的按钮以调用该方法addNewRow()。

jButton1.addActionListener(new ActionListener()
{
    @Override
    public void actionPerformed(ActionEvent e)
    {
       addNewRow();
    }
});

如果有不清楚的地方，请随时问我。