GridBagLayout无法正确布局

1 回答

• 4

  那么你可以通过使用 GridBagLayout 轻松完成此任务 .

  考虑 contentPane 并将 GridBagLayout 作为其布局，您现在可以将 JPanel 分为三个部分 . 单个左侧 JPanel （带有GridBagLayout，其中包含 RED ， BLACK 和 BLUE JPanel s），右侧包含两个 JPanel ，即 GREEN 和 MAGENTA .

  ------------------------
  |  left   | green JPanel |
  | JPanel  |______________|
  |  with   |magenta Jpanel|
  |3 JPanel |              |
  |________________________|
  

  现在左边 JPanel 将 RED ， BLACK 和 BLUE JPanel 放在其自身上， GridBagLayout 为 Layout Manager ， RED and BLUE 为 weighty = 0.1 ， BLACK 为 weighty = 0.8

  请参阅此示例代码：

  import java.awt.*;
  import javax.swing.*;
  
  public class GridBagExample {
      private JPanel leftPanel;
      private JPanel redPanel;
      private JPanel blackPanel;
      private JPanel bluePanel;
      private JPanel greenPanel;
      private JPanel magentaPanel;
  
      private GridBagConstraints gbc;
  
      public GridBagExample() {
          gbc = new GridBagConstraints();
          gbc.anchor = GridBagConstraints.FIRST_LINE_START;
      }
  
      private void displayGUI() {
          JFrame frame = new JFrame("GridBagLayout Example");
          frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
  
          JPanel contentPane = new JPanel(new GridBagLayout());
  
          leftPanel = getPanel(Color.WHITE);
          leftPanel.setLayout(new GridBagLayout());
          redPanel = getPanel(Color.RED.darker());
          blackPanel = getPanel(Color.BLACK);
          bluePanel = getPanel(Color.CYAN.darker().darker());
          greenPanel = getPanel(Color.GREEN.darker().darker());
          magentaPanel = getPanel(Color.MAGENTA);
          /**
            * @param : 
            * leftPanel : JPanel (with GridBagLayout), on which
            *               all other components will be placed.
            * redPanel : JPanel, which will be added to the leftPanel
            * 0 : specifies the grid X, which in this case is 0
            * 0 : specifies the grid Y, which in this case is 0
            * 1 : specifies the width for this grid (cell), we keeping 
            *     this default as 1
            * 1 : specifies the height for this grid (cell), we keeping
            *     this default as 1
            * GridBagConstraints.BOTH : allows JPanel to expand in both
            *     directions as the containing container expands (in 
            *     this case redPanel will expand both HORIZONTALLY and
            *     VERTICALLY, as leftPanel will expand)
            * weightx : This is the actual width the redPanel will occupy
            *           relative to all other components on the leftPanel
            * weighty : This is the actual height the redPanel will occupy
            *           relative to all other components on the leftPanel
            */
          addComp(leftPanel, redPanel, 0, 0, 1, 1,
                          GridBagConstraints.BOTH, 1.0, 0.1);
          addComp(leftPanel, blackPanel, 0, 1, 1, 1,
                          GridBagConstraints.BOTH, 1.0, 0.8);
          addComp(leftPanel, bluePanel, 0, 2, 1, 1,
                          GridBagConstraints.BOTH, 1.0, 0.1);
          addComp(contentPane, leftPanel, 0, 0, 1, 2,
                          GridBagConstraints.BOTH, 0.5, 1.0);
          addComp(contentPane, greenPanel, 1, 0, 1, 1,
                          GridBagConstraints.BOTH, 0.5, 0.3);
          addComp(contentPane, magentaPanel, 1, 1, 1, 1,
                          GridBagConstraints.BOTH, 0.5, 0.7);
  
          frame.setContentPane(contentPane);
          /*
           * Once you will add components to these
           * JPanels, then use pack(), instead of
           * setSize(). The use of the latter is 
           * just for illustration purpose only
           */
          //frame.pack();
          frame.setSize(300, 300);
          frame.setLocationByPlatform(true);
          frame.setVisible(true);
      }
  
      private void addComp(JPanel panel, JComponent comp,
                              int x, int y, int width, int height,
                              int fill, double weightx, double weighty) {
          gbc.gridx = x;
          gbc.gridy = y;
          gbc.gridwidth = width;
          gbc.gridheight = height;
          gbc.fill = fill;
          gbc.weightx = weightx;
          gbc.weighty = weighty;
  
          panel.add(comp, gbc);
      }
  
      private JPanel getPanel(Color backColor) {
          JPanel panel = new JPanel();
          panel.setOpaque(true);
          panel.setBackground(backColor);
  
          return panel;
      }
  
      public static void main(String[] args) {
          Runnable runnable = new Runnable() {
              @Override
              public void run() {
                  new GridBagExample().displayGUI();
              }
          };
          EventQueue.invokeLater(runnable);
      }
  }
  

  这是相同的输出：

  

  回复于 2024-05-05T11:22:48+08:00