CODEWITHSUNDEEP
javaswing
tssguy123
tssguy123

Reputation: 185

How to make this ActionListener completely re-draw JFrame?

private static final long serialVersionUID = 1L;
String[] options = {"1","2","4","8","16","20","40","100","400"} ;
int[] optionsNum = {1,2,4,8,16,20,40,100,400};
JComboBox<String> box = new JComboBox<>(options);
JLabel prompt = new JLabel("How complex do you want the circle to be?");
ImageIcon image;

Circle p = new Circle(1);
int boxindex = 0;

public CircleDrawer(){
    image = new ImageIcon(p.getImage());
    box.setSelectedIndex(boxindex);
    setLayout(new FlowLayout());
    add(new JLabel(image));
    add(prompt);
    add(box);
    pack();
    setSize(851, 950);
    setTitle("Circle Drawer");
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    box.addActionListener(this);

}

public void actionPerformed(ActionEvent e) {
    if (e.getSource() == box){
        boxindex = box.getSelectedIndex();
        p.setComplexity(optionsNum[boxindex]);
        image = new ImageIcon(p.getImage());
        add(new JLabel(image));
        validate();
    }
}

public static void main(String[] args) {
    CircleDrawer f = new CircleDrawer();
    f.setVisible(true);
}

Basically, I have this code. It references a class called Circle, which calculates some points on the outer edge of a circle and draws them using a paintComponent. In this class, there is a method called getImage, which takes what the paintComponent method drew and puts it into a BufferedImage. 

public BufferedImage getImage() {

    BufferedImage hello = new BufferedImage(805, 805, BufferedImage.TYPE_INT_ARGB);
    Graphics g = hello.getGraphics();
    paintComponent( g );

    return hello;
}

Like so.

The problem I'm running into is that I can't find a way for it to completely re-draw the JFrame. I've tried clearing the JFrame within the actionPerformed method using removeAll() and then COMPLETELY setting up the frame all over again (add all of the components, pack, setSize, setTitle, etc) and then repaint, revalidate, or just validate it.

If I simply have it add the image and then validate it, I can see the image being updated, but it's just getting tacked on at the end of the JFrame (just like I would expect it to using a FlowLayout) but that's not the behavior I need. It just shows that it is sort of working.

My question is this: How do I make it re-draw the JFrame when the user changes options inside of the JComboBox?

Upvotes: 0

Views: 90

Answers (1)

camickr
camickr

Reputation: 324118

Graphics g = hello.getGraphics();
paintComponent( g );

Don't use getGraphics() and never invoke paintComponent() directly. Swing will invoke the proper painting methods are required.

 add(new JLabel(image));
 validate();

When you add (remove) components from a visible GUI the general structure of the code is:

add(...);
revalidate(); // to invoke the layout manager
repaint(); to repaint the components

Upvotes: 2

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