Question

I realise this code looks, pointless, I’ve just got rid of the irrelevent stuff to show the structure

class Drawer extends JComponent {
  public Drawer(int[] data) {

    System.out.println("drawer");

    for(int x = 0; x < data.length; x++){}
      //work out what to draw
    repaint();
  }

  public void paintComponent(Graphics g) {
    super.paintComponent(g);     
    System.out.println("drawerpC"); //check to see if it is called
    //draw stuff
  }  
}

In a separate file, a new instance of Drawer is called regularly. Every time it is called, data is different, and so every time Drawer is called, paintComponent needs to be called.

I have this code in that other file:

Drawer d = new Drawer(data);
myGUI.con.add(d); //myGUI.con is a previously set up container

repaint() is not causing paintComponent to be called (otherwise you’d see the stdout), so how can I force paintComponent to be called for every calling to Drawer?

Answer 1

Store the int[] as a class attribute. Move //work out what to draw into paintComponent(Graphics).