Java GridBagLayout - 在不同容器中的列宽相等

Question

我一直在GridBagLayout出现问题几个小时，但我无法解决它。我在JFrame中有两个JPanel（包含JTextFields）。第一个（上部）JPanel有一个3行2列的网格。第二个（较低）的JPanel有一个3行3列的网格。我需要将它们对齐，如下图所示（上面的JPanel表示空白中的白色列;数字表示相对宽度），并且随着窗口大小的变化，比例要一致。

是我的代码是下一个：

import java.awt.EventQueue; 
    import java.awt.FlowLayout; 
    import java.awt.GridBagConstraints; 
    import java.awt.GridBagLayout; 
    import javax.swing.JFrame; 
    import javax.swing.JLabel; 
    import javax.swing.JPanel; 
    import javax.swing.JTextField; 
    import javax.swing.border.TitledBorder; 

    public class FrameWithTwoPanels { 

     private GridBagConstraints constraints; 
     private JFrame frame; 

     public static void main(String[] args) { 
      EventQueue.invokeLater(new Runnable() { 
       public void run() { 
        try { 
         FrameWithTwoPanels window = new FrameWithTwoPanels(); 
         window.frame.setVisible(true); 
        } catch (Exception e) { 
         e.printStackTrace(); 
        } 
       } 
      }); 
     } 

     public FrameWithTwoPanels() { 
      initialize(); 
     } 

     private void initialize() { 
      frame = new JFrame(); 
      frame.setBounds(100, 100, 800, 800); 
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 

      // Populate the frame with two Panels 
      frame.setLayout(new GridBagLayout()); 
      GridBagConstraints c = new GridBagConstraints(); 
      c.gridwidth = GridBagConstraints.REMAINDER; 
      c.weightx = 1; 
      c.fill = GridBagConstraints.HORIZONTAL; 
      c.gridy = 0; 
      // PANEL 1: 3 rows and 2 columns 
      frame.add(this.createPanel(3, 2), c); 
      // PANEL 2: 3 rows and 3 columns 
      c.gridy = 1; 
      frame.add(this.createPanel(3, 3), c); 

      frame.pack(); 
      frame.setLocationRelativeTo(null); 
     } 

     private JPanel createPanel(int numrows, int numcols){ 
      JPanel panel = new JPanel(); 
      panel.setLayout(new GridBagLayout()); 
      constraints = new GridBagConstraints(); 
      //constraints.fill = GridBagConstraints.BOTH; 
      for(int row=0; row<numrows; row++){ 

       for(int col =0; col<numcols; col++){ 

        JTextField component = new JTextField(row + "-" + col); 

        if(col == 0){ 
         constraints.weightx = 0.5; 
        }else if(col == 1){ 
         constraints.weightx = 0.4; 
        }else if(col == 2){ 
         constraints.weightx = 0.1; 
        }   
        constraints.gridy = row; 
        constraints.gridx = col; 
        panel.add(component, constraints); 

        if(numcols == 2 && col == 1){ 
         // Add auxiliar panel 
         constraints.weightx = 0.1; 
         constraints.gridx = col + 1; 
         panel.add(new JLabel()); 
        } 
       } 
      } 
      panel.setBorder(new TitledBorder("Number of columns: " + numcols)); 
      return panel;  
     } 
    } 

的代码给出了截图所示的形式：

Answer 1

这是你真正最好使用情况普通的GridLayout。我想下面的代码你想要做什么：

private JPanel createPanel(int numrows, int numcols) { 
    JPanel panel = new JPanel(); 
    panel.setLayout(new GridLayout(numrows, 3)); 
    for (int row = 0; row < numrows; row++) { 
     for (int col = 0; col < numcols; col++) { 
      JTextField component = new JTextField(row + "-" + col); 
      panel.add(component); 
      if (numcols == 2 && col == 1) { 
       JPanel spacer = new JPanel(); 
       panel.add(spacer); 
      } 
     } 
    } 
    panel.setBorder(new TitledBorder("Number of columns: " + numcols)); 
    return panel; 
}