Java swing GridBagLayout space left

Question

I am stuck in java GridBagLayout. There is only one problem left. I want the middle panel ("Test Label 2") to leave all the vertical spaces on the left.

How to do it?

Thanks.

package com; import java.awt.Color; import java.awt.GridBagConstraints; import java.awt.GridBagLayout; import java.awt.GridLayout; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; import javax.swing.border.LineBorder; import javax.swing.border.TitledBorder; public class Test1 { private void _panel1(JPanel panel){ panel.setBorder(new LineBorder(Color.RED)); panel.setLayout(new GridBagLayout()); JPanel panel1 = new JPanel(); panel1.add(new JLabel(" Testing Label 1 ")); panel1.setBorder(new TitledBorder("P1")); GridBagConstraints c = new GridBagConstraints(); c.fill = GridBagConstraints.HORIZONTAL; c.anchor = GridBagConstraints.NORTH; c.gridx = 0; c.gridy = 0; c.weightx = 1.0; c.weighty = 0.0; panel.add(panel1, c); JPanel panel2 = new JPanel(); panel2.add(new JLabel(" Testing Label 2")); panel2.setBorder(new TitledBorder("P2")); c = new GridBagConstraints(); c.fill = GridBagConstraints.HORIZONTAL; c.anchor = GridBagConstraints.NORTH; c.gridx = 0; c.gridy = 1; c.weightx = 1.0; c.weighty = 1.0; panel.add(panel2, c); JPanel panel3 = new JPanel(); panel3.setBorder(new TitledBorder("P3")); c = new GridBagConstraints(); c.fill = GridBagConstraints.HORIZONTAL; c.anchor = GridBagConstraints.NORTH; c.gridx = 0; c.gridy = 2; c.weightx = 1.0; c.weighty = 0.0; panel3.setLayout(new GridLayout(5,1)); for(int i=0; i<5; i++){ panel3.add(new JButton("button "+i)); } panel.add(panel3, c); } public Test1(){ JFrame frame = new JFrame(); frame.setTitle("test 1"); frame.getContentPane().setLayout(new GridLayout(1,3)); JPanel panel1 = new JPanel(); _panel1(panel1); JPanel panel2 = new JPanel(); JPanel panel3 = new JPanel(); frame.getContentPane().add(panel1); frame.getContentPane().add(panel2); frame.getContentPane().add(panel3); frame.setSize(800, 600); frame.setVisible(true); } public static void main(String[] args) { Test1 t = new Test1(); } } 

Answer 1

I just changed one line (27):

  final JPanel panel2 = new JPanel(); panel2.add(new JLabel(" Testing Label 2")); panel2.setBorder(new TitledBorder("P2")); c = new GridBagConstraints(); // You have to use BOTH for the panel to take // all vertical and horizontal space c.fill = GridBagConstraints.BOTH; 

You set the grid limit for panel2 to HORIZONTAL .

Hello,

Answer 2

Consider changing the GridBagConstraint fill field for BOTH for panel2:

  panel2.setBorder(new TitledBorder("P2")); c = new GridBagConstraints(); c.fill = GridBagConstraints.BOTH; // ***** c.anchor = GridBagConstraints.NORTH; 

Either this, or for a much simpler solution, just use BorderLayout instead:

  panel.setBorder(new LineBorder(Color.RED)); panel.setLayout(new BorderLayout()); JPanel panel1 = new JPanel(); panel1.add(new JLabel(" Testing Label 1 ")); panel1.setBorder(new TitledBorder("P1")); panel.add(panel1, BorderLayout.NORTH); JPanel panel2 = new JPanel(); panel2.add(new JLabel(" Testing Label 2")); panel2.setBorder(new TitledBorder("P2")); panel.add(panel2, BorderLayout.CENTER); JPanel panel3 = new JPanel(); panel3.setBorder(new TitledBorder("P3")); panel3.setLayout(new GridLayout(5, 1)); for (int i = 0; i < 5; i++) { panel3.add(new JButton("button " + i)); } panel.add(panel3, BorderLayout.SOUTH);