在 jframe 中设置按钮的位置不起作用

Question

I have a method that is just adding a button to a JPanel. I have a problem however, where there are some properties of this button that I cannot modify.

setBackground and setLocation method don't affect the button at all. I'm trying to move the button to the bottom of the JPannel but nothing seems to happen when I try setting the horizontal alignment or location.

    public static void initButtons() {
        JButton purchaseButton = new JButton();
        purchaseButton.setText("Proceed to Checkout");
        purchaseButton.setPreferredSize(new Dimension(200,50));
        purchaseButton.setIcon(new ImageIcon("/Users/alecr/eclipse-workspace/MakingPurchases/src/shopping_cart_sprite.png"));
// set location method not working
        purchaseButton.setLocation(25, 600);

        JPanel firstPanel = new JPanel(); 
        firstPanel.setBounds(25, 40, 300, 700);
        firstPanel.setBackground(new java.awt.Color(90,90,100));
        firstPanel.setBorder(BorderFactory.createStrokeBorder(new BasicStroke(3.0f), new Color(70,70,80)));
        frame.add(firstPanel);

        firstPanel.add(purchaseButton);
    }

Answer 1

Instead of using setLocation and setBounds for each component, you should use a proper LayoutManager and let it do the work for you. Having hard coded sizes and locations will not allow your application be scalable for different screen sizes and your JFrame will not be able to be resizable, which is not so user-friendly.

However, if you insist of using absolute-hard coded values (coordinates and dimensions) you must remove the layout manager from the container (a JPanel uses FlowLayout by default), because like I mentioned, it takes care of such things. In order to do that:

JPanel panel = new JPanel(null); //null layout manager allows absolute values