JTextField flashing white when typing

Question

I am actively rendering using a BufferStrategy in my own render loop. Here is the method that takes care of the repainting.

public void handleRepaint() {
    try {
        Graphics g = buffer.getDrawGraphics();
        render(g);
        g.dispose();
        if (!buffer.contentsLost()) {
            buffer.show();
        }
    } catch (IllegalStateException e) {
    }
}

The details of the render(Graphics g) method are a bit unnecessary to display. Basically I am doing my custom repainting, and then calling contentPane.paintComponents(Graphics g) , with the contentPane being the content pane of my JFrame , cast into a JComponent .

This works perfectly when the components are opaque. However, when any component is transparent, weird things start to happen. For example, if I create a JButton and add it to the JPanel , the background of the button occasionally flashes white when the mouse enters/exists it. When I add a JTextField , typing will occasionally cause the entire text field to flash white.

I can't figure out what is going on. It obviously has something to do with the active rendering, but I can't figure out what it is. Even with the tutorial I used , the same thing happens when I set any of their JButtons to be transparent.

I'm at a loss as to how to fix this problem. With the buttons, disabling the rollover works, but I don't want the rollover to be disabled. And with JTextFields and other components, there is no rollover to be disabled, and I can't just disable typing.

So if anyone has a solution to this, please help.

PS: The repaint code for the swing components are all run on the EDT.

Answer 1

However, when any component is transparent, weird things start to happen.

Whenever I see a comment like that I suggest you check out Backgrounds With Transparency for potential problems and a couple of solutions.

Basically, because the background is transparent you need to make the component non-opaque so its parents background is painted first, then you need to do custom painting to paint your components background.