Hey everyone, I've just started getting into Swing and have encountered a weird problem. I'm trying to get a grid which will expand when left-clicked and retract when right-clicked. This works fine, but the positioning seems strange to me. I want the grid to start from the top-left corner, but it seems like there is some kind of invisible border there. Has anyone else seen this before? I'm sure I'm just making some newbie mistake
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| public class GridScroller extends JPanel implements MouseListener{
public final static String PROG_NAME = "GridScroller";
public JPanel drawingPane;
public int clickCounter = 0;
public GridScroller(){
super(new BorderLayout());
System.out.println(PROG_NAME + ": constructor entered");
drawingPane = new DrawingPane();
drawingPane.setBackground(Color.CYAN);
drawingPane.addMouseListener(this);
JScrollPane scroller = new JScrollPane(drawingPane);
drawingPane.setLocation(0,0);
scroller.setPreferredSize(new Dimension(600, 450));
scroller.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_ALWAYS);
scroller.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
add(scroller);
}
public class DrawingPane extends JPanel{
protected void paintComponent(Graphics g){
super.paintComponent(g);
for(int i = 0; i < clickCounter; i++){
for(int j = 0; j < clickCounter; j++){
g.setColor(Color.BLACK);
g.drawRect(20, 20, i * 20 + 0, j * 20 + 0);
}
}
}
}
public void mouseReleased(MouseEvent e){
if(e.getButton() == MouseEvent.BUTTON1){
clickCounter++;
}
if(e.getButton() == MouseEvent.BUTTON3){
clickCounter--;
}
drawingPane.setPreferredSize(new Dimension((clickCounter + 2) * 20, (clickCounter + 2) * 20));
drawingPane.repaint();
drawingPane.revalidate();
System.out.println("Mouse event captured");
}
public void mouseClicked(MouseEvent e){}
public void mouseEntered(MouseEvent e){}
public void mouseExited(MouseEvent e){}
public void mousePressed(MouseEvent e){}
public static void createAndShowGUI(){
System.out.println(PROG_NAME + ": createAndShowGUI entered");
JFrame frame = new JFrame("GridScroller");
frame.setLayout(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JComponent newContentPane = new GridScroller();
newContentPane.setOpaque(true);
frame.setContentPane(newContentPane);
newContentPane.setLocation(0,0);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args){
System.out.println(PROG_NAME + ": main entered");
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run(){
createAndShowGUI();
}
});
}
} |
