[Java Swing 大富翁] swing下使用JPanel 模擬 按鈕實現。

按鈕點擊須要讓jpanel實現鼠標點擊事件。跟隨着效果的切換，便可實現按鈕的效果。

舉個例子：

有一個"購買"按鈕，images以下

 

normal:  

mouseOver: 

disabled: 

pressed:

 

代碼以下：

public class ShopButton extends JPanel implements MouseListener {
    
    private Shop shopUI;
    
    private Image[] img;
    
    private Image normalImage;
    private Image rolloverImage;
    private Image pressedImage;
    private Image disabledImage;
    
    private Image currentImage;

    private boolean enabled = true;
    
    private String name = null;

    private Control control;
    
    public ShopButton(Shop shopUI,String name, int x, int y,Control control) {
        this.shopUI = shopUI;
        this.name = name;//設置名稱
        this.control = control;
        this.img = this.shopUI.createCardImg(name);//這裏就是使用工廠模式獲取img資源
        this.normalImage = this.img[0];
        this.rolloverImage = this.img[1];
        this.pressedImage =this.img[2];
        this.disabledImage = this.img[3];
        this.currentImage = normalImage;
        this.setBounds(x, y, this.img[0].getWidth(null), this.img[0].getHeight(null));
        this.addMouseListener(this);
    }

    
    public boolean isEnabled() {
        return enabled;
    }

    public void setEnabled(boolean enabled) {
        this.enabled = enabled;
    }

    public void paint(Graphics g) {
        this.setOpaque(false); // 背景透明
        if (enabled){
            g.drawImage(currentImage, this.getX(), this.getY(), this.getWidth(),
                    this.getHeight(), this);
        } else if (!(name.equals("buy") || name.equals("cancel"))){
            g.drawImage(disabledImage, this.getX(), this.getY(), this.getWidth(),
                    this.getHeight(), this);
        }
    }

    @Override
    public void mouseClicked(MouseEvent e) {

    }

    @Override
    public void mousePressed(MouseEvent e) {
            currentImage = pressedImage;
            if(enabled){
                if (this.name.equals("close")){//退出商店
                    this.shopUI.moveToBack();
                    this.control.exitShop();
                } else if (this.name.equals("cancel")){//取消當前選擇
                    this.shopUI.setChooseCard(null);
                } else if (this.name.equals("buy")){//購買當前選擇
                    this.control.buyCard(this.shopUI.getShop());
                } else {
                    this.shopUI.setChooseCard(this);
                }
            }
    }

    @Override
    public void mouseReleased(MouseEvent e) {
            currentImage = rolloverImage;
    }

    @Override
    public void mouseEntered(MouseEvent e) {
            currentImage = rolloverImage;
    }

    @Override
    public void mouseExited(MouseEvent e) {
            currentImage = normalImage;
    }
}

適當的擴展能夠作成通用類，可以模擬各種按鈕類。

如下是 mini大富翁內的商店界面：紅框內是擴展實現