Using setBounds or setLocation on JTextArea isn't working

Question

I am adding a JTextArea to my JPanel with this code:

commentTextArea.setLineWrap(true);
commentTextArea.setWrapStyleWord(true);
commentTextArea.setVisible(true);
this.add(commentTextArea);
commentTextArea.setBounds(0, 0, 100, 100);
//commentTextArea.setLocation(0, 0);

Whenever I use setLocation(0,0), the JTextArea never moves. It is always in the top middle of the screen, not at (0,0). The same goes for setBounds(0,0,100,100) BUT the height and width are set this way, just not the location. Why is this?

Full Code

import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;

import javax.swing.JFrame;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.JTextArea;

public class UMLEditor {

    public static void main(String[] args) {
        JFrame frame = new UMLWindow();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setBounds(30, 30, 1000, 700);
        frame.getContentPane().setBackground(Color.white);
        frame.setVisible(true);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }
}

class UMLWindow extends JFrame {
    Canvas canvas = new Canvas();

    private static final long serialVersionUID = 1L;

    public UMLWindow() {
        addMenus();
    }

    public void addMenus() {

        getContentPane().add(canvas);

        JMenuBar menubar = new JMenuBar();

        JMenuItem newTextBox = new JMenuItem("New Text Box");
        newTextBox.setMnemonic(KeyEvent.VK_E);
        newTextBox.setToolTipText("Exit application");
        newTextBox.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent event) {
                canvas.addTextBox();
            }
        });

        menubar.add(newTextBox);

        setJMenuBar(menubar);

        setSize(300, 200);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
    }
}

class Canvas extends JPanel {

    JTextArea commentTextArea = new JTextArea(10, 10);

    public Canvas() {
        this.setOpaque(true);

    }

    public void addTextBox() {

        commentTextArea.setLineWrap(true);
        commentTextArea.setWrapStyleWord(true);
        commentTextArea.setVisible(true);
        commentTextArea.setLocation(0, 0);
        this.add(commentTextArea);
        commentTextArea.setBounds(0, 0, 100, 100);

        revalidate();
        repaint();
    }
}

Avoid using `null` layouts, pixel perfect layouts are an illusion within modern ui design. There are too many factors which affect the individual size of components, none of which you can control. Swing was designed to work with layout managers at the core, discarding these will lead to no end of issues and problems that you will spend more and more time trying to rectify. Take a look at [Why is it frowned upon to use a null layout in SWING?](http://stackoverflow.com/questions/6592468/why-is-it-frowned-upon-to-use-a-null-layout-in-swing) — MadProgrammer, Oct 27 '14 at 23:44
Also take a look at [Laying Out Components Within a Container](http://docs.oracle.com/javase/tutorial/uiswing/layout/index.html) for more ideas — MadProgrammer, Oct 27 '14 at 23:46
`JTextArea commentTextArea = new JTextArea(10, 10);` .. `commentTextArea.setBounds(0, 0, 100, 100);` To change the size of a text area change the number of rows or columns, or the size of the font. To change the location, the easiest way is to add an `EmptyBorder`. See also: [Combinations of layout managers](http://stackoverflow.com/a/5630271/418556) and layout padding and borders for [white space](http://stackoverflow.com/a/17874718/418556). — Andrew Thompson, Oct 28 '14 at 00:12

score 7 · Accepted Answer · answered Oct 27 '14 at 23:43

Setting a component's position via setBounds(...) only works for null layouts, i.e.,

container.setLayout(null);`

but regardless of this, I'm going suggest that you not do this as this makes for very inflexible GUI's that while they might look good on one platform look terrible on most other platforms or screen resolutions and that are very difficult to update and maintain. Instead you will want to study and learn the layout managers and then nest JPanels, each using its own layout manager to create pleasing and complex GUI's that look good on all OS's.

Also there's a second hidden danger to setting the size of a JTextArea -- do this, and it will not work correctly in a JScrollPane, the usual place where JTextAreas reside, since it cannot expand correctly as lines of text are added. So it goes doubly so that you should never set the size of a JTextArea.

Ok, well actually I was more interested in setting the location and therefore won't need to resize it. But, I am planning on using this for click-and-dragging of the JTextArea around the JPanel so I will need to know where the JTextArea is and where it will have to move to — Harry, Oct 28 '14 at 00:32

Using setBounds or setLocation on JTextArea isn't working

1 Answers1