How to force a Jcomponent to appear in Java?

Question

If I have a listener that add JLabel dynamically, is there a way to force the component appear immediately?

I am working on a project that I have an ArrayList storing every dynamically added label. I have another method that involves drawing a line on the panel. It depends on the new JLabel location (x and y). Here is the code inside my listener:

panel.add(labelArrayList.get(index));
panel.repaint();
panel.revalidate();

drawLine();

where drawLine() is a method that simply draws a single line on the panel.

private void drawLine(){
    /*Draw from (x1,y1) to (x2,y2), where (x1,y1) is fixed at original and (x2,y2) is the location of the newly added JLabel*/
    graphics2d.drawLine(x1, y1, x2, y2);
}

When I was in debug mode, I saw the item is not added after repaint() and revalidate() is called. Therefore, I cannot get the location of the newly added Label. The new JLabel appears after the drawLines() method is called.

I want the new label added before the drawLine() is called. Is there any way to make it work?

Answer 1

调用doLayout() （而不是repaint()或revalidate() ）可以。