java - 分割paintComponent方法

Question

我是 GUI 新手，正在编写一个程序来在图表上显示 NameRecord 的多个条目。当我只需要放入一个条目时，我在paintComponent中启动了整个框架。

但是，现在我需要修改它，以便可以存储多个NameRecords条目，我决定使用ArrayList来存储。然后我希望能够搜索、清除这些条目。但我在paintComponent 中的内容太困惑了。

如何修改此方法，以便拥有单独的类来存储条目并执行其他方法？因为我无法在此类之外引用 g。

@Override
public void paintComponent(Graphics g) {

    super.paintComponent(g);

    w = getWidth();
    h = getHeight();

    //draw horizontal lines
    g.drawLine(0, 20, w, 20);
    g.drawLine(0, h - 20, w, h - 20);

    //draw vertical lines
    for (int i = 1; i < 12; i++) {
        g.drawLine((w / 12) * i, 0, (w / 12) * i, h);
    }
    //draw lable of years
    g.drawString("   1900", 0, 13);
    g.drawString("   1900", 0, h - 7);

    int year = 1900;
    for (int i = 1; i < 12; i++) {
        g.drawString("   " + Integer.toString(year + (i * 10)), (w / 12 * i), 13);
        g.drawString("   " + Integer.toString(year + (i * 10)), (w / 12 * i), h - 7);
    }

    // draw line of rank
    if (nameData != null) {
        nameList.add(nameData);
        for (int i = 0; i < 11; i++) {
            g.drawLine((w / 12 * i), convertValue(nameData.getRank(i)),
                    (w / 12) * (i + 1), convertValue(nameData.getRank(i + 1)));
        }

        for (int i = 0; i < 12; i++) {
            String label = " ";
            label = (nameData.getName() + " " + nameData.getRank(i));
            g.drawString(label, (w / 12 * i), convertValue(nameData.getRank(i)));
        }
    }
}

我还使用了另一个类来完成所有 GUI 显示(我不确定这是否是这样说的，但它调用了 actionPerformed 方法)。他们的联系让我有点困惑。我只是把它放在这里作为引用。

 @Override
public void actionPerformed(ActionEvent e) {
    String s = e.getActionCommand();

    if (s.equalsIgnoreCase("graph")) {
        doGraph();
    } else if (s.equalsIgnoreCase("search")) {
        findName(inputField.getText());
    } else if (s.equalsIgnoreCase("clear all")) {
        clear();
        //– remove all names from the NameGraph

    } else if (s.equalsIgnoreCase("clear one")) {

        //remove the name that was added to the NameGraph earliest.
    } else if (s.equalsIgnoreCase("quit")) {
        setVisible(false);
        dispose();
        System.exit(0);
    } else {
        // This is the response to the Enter Key pressed in inputField.
        doGraph();
    }
}

Answer 1

How can I modify this method so that I have separate classes to store entries and perform other methods? Since I cannot refer to g outside of this class.

您将能够访问Graphics object g通过将其传递给方法或另一个类的方法:

//for example
class MyGraph{
    public void draw(Graphics g){
        //implements how the graph is drawn, for e.g:
        //g.drawLine(x, y);
    }
}

在显示绘图的面板类中:

class DisplayPanel extends JPanel{

    private MyGraph;

    public DisplayPanel(){
        MyGraph graph = new MyGraph();
    }

    @Override
    public void paintComponent(Graphics g){
        super.paintComponent(g);
        graph.draw(g);            //let the objects draw themselves
    }
}