Question

我正在尝试使用复合设计模式在JPanel上显示图标。我有一个扩展Icon的复合类，它有一个ArrayList，它包含一个实现Icon并扩展ImageIcon的自定义类。我想调用composites paintIcon（）方法并循环遍历ArrayList，并绘制所有包含的Icons。如果我只是调用ImageIcon并将其添加到我的面板，我可以在屏幕上绘制一个Icon。我不明白为什么从CompositeIcon调用的paintIcon（）不起作用。以下方法循环ArrayList，但似乎不从屏幕打印。当在GUI中调用setIcon（）时，不应该将它绘制到JPanel上吗？

@Override
public void paintIcon(Component c, Graphics g, int i, int i1) {
    for(int j = 0; j < icons.size(); j++){
        icons.get(j).paintIcon(c, g, listX.get(j), listY.get(j));
    }
}

到目前为止，我有一名测试员：

public class Display extends JFrame {


public CompositeIcons icons = new CompositeIcons();



public Display() throws MalformedURLException{
    super();

    this.setTitle("Composite Pattern");
    this.setSize(600, 600);
    this.setLocationRelativeTo(null);
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    //this.setResizable(false);
    this.setLayout(new FlowLayout());


    ImageIcon image = new ImageIcon("discover.png");
    IconOne iconOne = new IconOne("discover.png");    

    icons.addIcon(iconOne, 10, 10);

    JPanel panel = new JPanel();
    JLabel label = new JLabel();
    label.setIcon(icons);
    panel.add(label);
    panel.setBorder(BorderFactory.createLineBorder(Color.GRAY, 1, true));
    panel.setPreferredSize(new Dimension(100,100));
    this.add(panel);
    this.setVisible(true);
}

}

和复合类：

public class CompositeIcons implements Icon {

private ArrayList<Icon> icons = new ArrayList();
private ArrayList<Integer> listX = new ArrayList();
private ArrayList<Integer> listY = new ArrayList();



public void addIcon(Icon icon, int x, int y){
    icons.add(icon);
    listX.add(x);
    listY.add(y);
}




@Override
public void paintIcon(Component c, Graphics g, int i, int i1) {
    for(int j = 0; j < icons.size(); j++){
        icons.get(j).paintIcon(c, g, listX.get(j), listY.get(j));
    }
}

@Override
public int getIconWidth() {
    return 40;
}

@Override
public int getIconHeight() {
    return 40;
}

}

和示例自定义Icon类：

public class IconOne extends ImageIcon implements Icon {

ImageIcon image;
int x, y;



public IconOne(String icon){
    super(icon);

}





@Override
public void paintIcon(Component cmpnt, Graphics grphcs, int i, int i1) {

}

@Override
public int getIconWidth() {
    throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}

@Override
public int getIconHeight() {
    throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}

Answer 1

从IconOne中删除paintIcon方法。该类已经扩展了实现它的ImageIcon。

使用带有Icon界面的复合设计模式

1 个答案: