JPanel Graphics clearing and repainting?

Question

I have a JPanel with a paintComponent() function. I\'ll call it once, then when the user clicks a different JButton, I\'ll set some fl

Answer 1

When you change a property of the panel then you need to invoke:

panel.repaint();

to cause the component to be repainted.

Then the first statement in the paintComponent() method should be:

super.paintComponent(g);

This will paint the background so you can now do your custom painting.

If you need more help then post your SSCCE that demonstrates the problem.

Answer 2

I would suggest calling revalidate(); instead of repaint(). revalidate() needs to be called when changing the size / layout or when you add/remove objects onto your jpanel and will update all of it's children. From what I can tell, you're still using the same paint object tho but changing it's layout.

Answer 3

To clear all previously drawn graphics, invoke g.clearRect(0, 0, getWidth(), getHeight()).

Answer 4

First, why not use an enum instead of a boolean?

enum Enum { 
    RECTANGLE,
    LINE,
    CIRCLE
}

Enum choice = RECTANGLE; //default to RECTANGLE

switch(choice) { 
   // case RECTANGLE, LINE, CIRCLE
}

With regards to your issue, can you answer my comments in your question?