GridBagLayout Java-weightY导致意外结果

Question

Trying to understand GridBagLayout and to fully work it. I'm trying some examples.

What my aim is to have three buttons directly below one another, and three buttons going across the screen.

Now I can get the first two rows working fine but the third row just goes straight to the middle of the screen.

import javax.swing.*;
import java.awt.*;

class test
{
    public static void main (String Args [])
    {
    //frame and jpanel stuff
    JFrame processDetail = new JFrame("Enter information for processes");
    JPanel panelDetail = new JPanel(new GridBagLayout());
    GridBagConstraints c = new GridBagConstraints();

    //label to add on top centre
    JButton label = new JButton("Proccess:");
    JButton label2 = new JButton("Arrival Time");
    JButton label3 = new JButton("Quanta Time");
    JButton label4 = new JButton("woooo");
    JButton label5 = new JButton("LdsdaE");
    JButton label6 = new JButton("affafa 666");

    //set size of frame and operation
    processDetail.setSize(500,500);
    processDetail.setDefaultCloseOperation(processDetail.EXIT_ON_CLOSE);

    //add the label to panel
    c.gridx = 0;
    c.gridy = 0;
    c.weightx = 0.5;
    //c.weighty = 0.5;
    c.fill = GridBagConstraints.NONE;
    c.anchor = GridBagConstraints.PAGE_START;
    panelDetail.add(label, c); //row 1 left

    c.gridx=1;
    panelDetail.add(label2, c); //row 1 middle

    c.gridx=2;
    panelDetail.add(label3, c); //row 1right

    c.weighty=0.1;
    c.gridx=0;
    c.gridy=1;
    panelDetail.add(label4, c); //row 2 left

    c.gridx=0;
    c.gridy=2;
    panelDetail.add(label5, c); //row 3 left

    processDetail.add(panelDetail);
    processDetail.setVisible(true);
    }
}

Edit

The button label 5, should be directly underneath the button label 4:

Like so:

[----LABEL 4 ---]
[----LABEL 5 ---]

at the moment its like:

[----LABEL 4 ---]


(dont want this gap between the two?)



[----LABEL 5 ---]

Answer 1

If you want the buttons all at the top with minimal gap between them, then either consider using a GridLayout and placing your JButtons into the GridLayout using JPanel, and then have your main JPanel use a BorderLayout add the button holding JPanel to your main JPanel BorderLayout.PAGE_START . Or the button holding JPanel could use a GridBagLayout, but I'd still nest it into a main JPanel and again at the BorderLayout.PAGE_START position. For example,

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.GridLayout;
import javax.swing.*;

public class Test4 extends JPanel {
   private static final long serialVersionUID = 1L;
   private static final int GAP = 3;

   public Test4() {
      JPanel buttonHoldingPanel = new JPanel(new GridLayout(3, 3, GAP, GAP));
      buttonHoldingPanel.add(new JButton("Process"));
      buttonHoldingPanel.add(new JButton("Arrival Time"));
      buttonHoldingPanel.add(new JButton("Quanta Time"));
      buttonHoldingPanel.add(new JButton("woooo"));
      buttonHoldingPanel.add(new JLabel());
      buttonHoldingPanel.add(new JLabel());
      buttonHoldingPanel.add(new JButton("LdsdaE"));
      buttonHoldingPanel.add(new JLabel());
      buttonHoldingPanel.add(new JLabel());

      setBorder(BorderFactory.createEmptyBorder(GAP, GAP, GAP, GAP));
      setLayout(new BorderLayout());
      add(buttonHoldingPanel, BorderLayout.PAGE_START);
      add(Box.createRigidArea(new Dimension(400, 300)), BorderLayout.CENTER);
   }

   private static void createAndShowGui() {
      Test4 mainPanel = new Test4();

      JFrame frame = new JFrame("Test4");
      frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
      frame.getContentPane().add(mainPanel);
      frame.pack();
      frame.setLocationByPlatform(true);
      frame.setVisible(true);
   }

   public static void main(String[] args) {
      SwingUtilities.invokeLater(new Runnable() {
         public void run() {
            createAndShowGui();
         }
      });
   }
}

Which creates this:

And as per my comment, if this image doesn't match the overall structure of the GUI you're trying to create, then please show us an image of just what it is you're trying to achieve.