How do I left and right align components in Swing?

Question

I have what appears to be a simple issue. I have some labels that I'd like to align to the left but when I resize, they start to drift towards the middle. This is going to throw off the alignment of other components I plan on adding. What do I do to keep them to the left?

It's short, easy code, not sure what my problem is here:

package com.protocase.notes.views;

import com.protocase.notes.model.Note;
import com.protocase.notes.model.User;
import java.awt.Component;
import java.util.Date;
import javax.swing.BoxLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.border.BevelBorder;

/**
 * @author dah01
 */
public class NotesPanel extends JPanel{

    public NotesPanel(Note note){
        this.setLayout(new BoxLayout(this,BoxLayout.Y_AXIS));
        JLabel creatorLabel = new JLabel("Note by "+note.getCreator()+ " @ "+note.getDateCreated());
        creatorLabel.setAlignmentX(JLabel.LEFT_ALIGNMENT);
        creatorLabel.setHorizontalAlignment(JLabel.LEFT);


        JTextArea notesContentsArea = new JTextArea(note.getContents());
        notesContentsArea.setEditable(false);
        JScrollPane scrollPane = new JScrollPane(notesContentsArea);

        JLabel editorLabel = new JLabel(" -- Last edited by "+note.getLastEdited() +" at "+note.getDateModified());
        editorLabel.setAlignmentX(Component.LEFT_ALIGNMENT);
        editorLabel.setHorizontalAlignment(JLabel.LEFT);

        this.add(creatorLabel);
        this.add(scrollPane);
        this.add(editorLabel);
        this.setBorder(new BevelBorder(BevelBorder.RAISED));
    }


    public static void main(String[] args) {
        JFrame frame = new JFrame("Notes Panel");
        Note note = new Note();
        User user = new User();
        user.setFirstName("d");
        user.setLastName("h");
        user.setUserID("dah01");
        note.setCreator(user);
        note.setLastEdited(user);
        note.setDateCreated(new Date());
        note.setDateModified(new Date());
        note.setContents("A TEST CONTENTS");
        NotesPanel np = new NotesPanel(note);

        JScrollPane scroll = new JScrollPane(np);
        frame.setContentPane(scroll);
        np.setVisible(true);
        frame.setVisible(true);
        frame.pack();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
}

Answer 1

If you want to align things in your panel, you have to align everything. You forgot to align your JScrollPane. If you add this line to your code, the alignment should be fixed for you:

    scrollPane.setAlignmentX(JScrollPane.LEFT_ALIGNMENT);

And what your new constructor would look like:

public NotesPanel(Note note){
    this.setLayout(new BoxLayout(this,BoxLayout.Y_AXIS));
    JLabel creatorLabel = new JLabel("Note by "+note.getCreator()+ " @ "+note.getDateCreated());
    creatorLabel.setAlignmentX(JLabel.LEFT_ALIGNMENT);
    creatorLabel.setHorizontalAlignment(JLabel.LEFT);


    JTextArea notesContentsArea = new JTextArea(note.getContents());
    notesContentsArea.setEditable(false);
    JScrollPane scrollPane = new JScrollPane(notesContentsArea);
    scrollPane.setAlignmentX(JScrollPane.LEFT_ALIGNMENT);

    JLabel editorLabel = new JLabel(" -- Last edited by "+note.getLastEdited() +" at "+note.getDateModified());
    editorLabel.setAlignmentX(Component.LEFT_ALIGNMENT);
    editorLabel.setHorizontalAlignment(JLabel.LEFT);

    this.add(creatorLabel);
    this.add(scrollPane);
    this.add(editorLabel);
    this.setBorder(new BevelBorder(BevelBorder.RAISED));
}

Answer 2

As per your comments, I would recommend you to go with some other layout, I would recommend MigLayout

Here you go with MigLayout:

import java.awt.EventQueue;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import net.miginfocom.swing.MigLayout;
import javax.swing.JLabel;
import javax.swing.JTextArea;


public class MigLayoutDemo {

    private JPanel contentPane;

    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    new MigLayoutDemo();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the frame.
     */
    public MigLayoutDemo() {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setBounds(100, 100, 450, 300);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        frame.setContentPane(contentPane);
        contentPane.setLayout(new MigLayout("", "[grow]", "[][grow][]"));

        JLabel lblLabel = new JLabel("Label 1");
            lblLabel.setBorder(BorderFactory.createLineBorder(Color.red));
        contentPane.add(lblLabel, "cell 0 0,alignx left");

        JTextArea textArea = new JTextArea();
        contentPane.add(textArea, "cell 0 1,grow");

        JLabel lblLabel_1 = new JLabel("Label 2");
            lblLabel_1.setBorder(BorderFactory.createLineBorder(Color.red));
        contentPane.add(lblLabel_1, "cell 0 2,alignx left");
        frame.setVisible(true);
    }

}

OUTPUT :

As you can see labels marked with red border are not stretched to the middle, they are left aligned .