CODEWITHSUNDEEP
javaswingjpanelpaintcomponent
Dipendra Kumar Mishra
Dipendra Kumar Mishra

Reputation: 311

Java swing draw objects over other components

I am trying to make a small paint program. I am drawing objects over a JPanel which is on top of JFrame (I am using Netbeans 6.9). I have some basic functionality like font, line and fillRectangle. I am using the standard method to draw which is to override paintComponent().

class .... extends JPanel
{
@Override
void paintComponents(Graphics g)
{
.......
}
}

The problem is that when I draw a text,line over a region then it is drawn behind it rather than on top of it. Basically I want to draw objects on top of all other objects that have previously been drawn on the JPanel. I really do not want to switch to other types of layered pane. One very naive method will be to undo every object and paint them in reverse order (last one first).

Upvotes: 4

Views: 6934

Answers (2)

Mahm00d
Mahm00d

Reputation: 3921

This is an old question, but I had the same problem and solved it by overriding paintChildren(Graphics g) instead of paintComponent.

As the Oracle documentation states, the order of execution for the three paint methods is:

protected void paintComponent(Graphics g) 
    protected void paintBorder(Graphics g)
      protected void paintChildren(Graphics g)

So, paintChildren(g) is run last, which means whatever we draw inside it is drawn on top of all previously drawn components.

Upvotes: 0

David Kroukamp
David Kroukamp

Reputation: 36423

You will need to override paintComponent(Graphics g) and do not forget to call super.paintComponent(Graphics g);

class .... extends JPanel
{
    @Override
    protected void paintComponent(Graphics g)
    {
        super.paintComponent(g);//honor paintComponent an call super to draw other components that were added to the JPanel
        .......
    }
}

You may also need to override getPreferredSize(..) of JPanel and return an appropriate size so the JPanel will be visible:

class .... extends JPanel
{
    @Override
    public Dimension getPreferredSize()
    {
        return new Dimension(300,300);
    }
}

EDIT:

Depending on what you are doing you may also want to have a look at the GlassPane which will allow you to set a transparent pane over the entire JFrame window and can be painted too, which will cause the graphics to be drawn above all others like so:

enter image description here

Upvotes: 4

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