Assistance with Java's grid bag layout?

Question

Well I'm trying to set it up to where the "enter your name" JLabel is displayed right next along the left hand side of the JTextField, sadly it's displayed at the center. What I'm talking about is the first JLabel and the first JTextArea, please disregard the rest of the code.

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

public class practice extends JFrame  {

    public static void main(String[] args){
        new practice();
    }

    public practice(){
        JPanel jp = new JPanel();

        jp.setLayout(new GridBagLayout());
        GridBagConstraints gbc = new GridBagConstraints();

        jp.add(new JLabel(""),gbc);

        gbc.gridx=0;
        gbc.gridy=1;
        jp.add(new JLabel("Enter your name\n"),gbc);

        gbc.gridx=0;
        gbc.gridy=0;
        jp.add(new JLabel(" "),gbc);

        gbc.gridx=0;
        gbc.gridy=0;
        jp.add(new JLabel(" "),gbc);

        gbc.insets = new Insets(30,0,0,0);
        gbc.gridx=0;
        gbc.gridy=1;
        jp.add(new JTextArea(3,30),gbc);

        gbc.insets = new Insets(10,0,0,0);
        gbc.gridx=0;
        gbc.gridy=2;
        jp.add(new JTextArea(3,10),gbc);

        gbc.insets = new Insets(10,0,0,0);
        gbc.gridx=0;
        gbc.gridy=3;
        jp.add(new JTextArea(3,10),gbc);

        gbc.gridx=0;
        gbc.gridy=0;
        jp.add(new JRadioButton(""),gbc);

        gbc.gridx=0;
        gbc.gridy=0;
        jp.add(new JRadioButton (""),gbc);

        gbc.gridx=0;
        gbc.gridy=0;
        jp.add(new JRadioButton(""),gbc);

        this.add(jp);
        setTitle("Card");
        setSize(700,500);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setVisible(true);
    }
}

Answer 1

I recommend creating a GridBagConstraints for each Swing component you want to put in the GUI. That way, you don't have to remember any defaults and you specify each of the parameters for every component.

Here's a JDialog where I used the GridBagLayout.

And here's the code for the JDialog.

package com.ggl.sudoku.solver.view;

import java.awt.Component;
import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class SolutionDialog {

    protected static final Insets   buttonInsets    = new Insets(10, 10, 0, 10);

    private int                     singleCount;
    private int                     guessCount;

    private long                    elapsedTime;

    private JDialog                 dialog;

    private SudokuFrame             frame;

    public SolutionDialog(SudokuFrame frame, int singleCount, int guessCount,
            long elapsedTime) {
        this.frame = frame;
        this.singleCount = singleCount;
        this.guessCount = guessCount;
        this.elapsedTime = elapsedTime;
        createPartControl();
    }

    private void createPartControl() {
        dialog = new JDialog(frame.getFrame(), "Statistics");
        dialog.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);

        JPanel mainPanel = new JPanel();
        mainPanel.setLayout(new BoxLayout(mainPanel, BoxLayout.Y_AXIS));

        JPanel resultsPanel = new JPanel();
        resultsPanel.setLayout(new GridBagLayout());

        int gridy = 0;

        JLabel singleCountLabel = new JLabel("Cells with one possible number:");
        addComponent(resultsPanel, singleCountLabel, 0, gridy, 1, 1,
                buttonInsets, GridBagConstraints.LINE_START,
                GridBagConstraints.HORIZONTAL);

        String s = singleCount + " cells";
        JLabel singleCountString = new JLabel(s);
        addComponent(resultsPanel, singleCountString, 1, gridy++, 1, 1,
                buttonInsets, GridBagConstraints.LINE_START,
                GridBagConstraints.HORIZONTAL);

        JLabel guessCountLabel = new JLabel("Cells where the solver guessed:");
        addComponent(resultsPanel, guessCountLabel, 0, gridy, 1, 1,
                buttonInsets, GridBagConstraints.LINE_START,
                GridBagConstraints.HORIZONTAL);

        s = guessCount + " cells";
        JLabel guessCountString = new JLabel(s);
        addComponent(resultsPanel, guessCountString, 1, gridy++, 1, 1,
                buttonInsets, GridBagConstraints.LINE_START,
                GridBagConstraints.HORIZONTAL);

        JLabel elapsedTimeLabel = new JLabel("Elapsed Time:");
        addComponent(resultsPanel, elapsedTimeLabel, 0, gridy, 1, 1,
                buttonInsets, GridBagConstraints.LINE_START,
                GridBagConstraints.HORIZONTAL);

        s = elapsedTime + " milliseconds";
        JLabel elapsedTimeString = new JLabel(s);
        addComponent(resultsPanel, elapsedTimeString, 1, gridy++, 1, 1,
                buttonInsets, GridBagConstraints.LINE_START,
                GridBagConstraints.HORIZONTAL);

        mainPanel.add(resultsPanel);

        JPanel buttonPanel = new JPanel();
        buttonPanel.setLayout(new FlowLayout());

        JButton okButton = new JButton("OK");
        okButton.setAlignmentX(JButton.RIGHT_ALIGNMENT);
        okButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent event) {
                dialog.setVisible(false);
                dialog.dispose();
            }
        });
        buttonPanel.add(okButton);

        mainPanel.add(buttonPanel);

        dialog.add(mainPanel);
        dialog.pack();
        dialog.setBounds(getBounds());
        dialog.setVisible(true);
    }

    private void addComponent(Container container, Component component,
            int gridx, int gridy, int gridwidth, int gridheight, Insets insets,
            int anchor, int fill) {
        GridBagConstraints gbc = new GridBagConstraints(gridx, gridy,
                gridwidth, gridheight, 1.0D, 1.0D, anchor, fill, insets, 0, 0);
        container.add(component, gbc);
    }

    protected Rectangle getBounds() {
        Rectangle f = frame.getBounds();
        Rectangle d = dialog.getBounds();
        d.x = f.x + (f.width - d.width) / 2;
        d.y = f.y + (f.height - d.height) / 2;
        return d;
    }

}