Question

我正在尝试在JFrame内的MainPanel内的JPanel中绘制一个Rectangle。在Main Class中，我初始化一个RoomView：

roomView = new RoomView(newropc,"Default");

然后我执行：

private void init_panels() {
    mainPanel.setLayout(new BorderLayout());
    mainPanel.add(toolsPanel,BorderLayout.SOUTH);
    mainPanel.add(roomView,BorderLayout.EAST);
    mainPanel.add(libraryPanel,BorderLayout.WEST);
}

然后课堂视图执行：

public class RoomView extends JPanel{
    private RoomPController rpc;
    private double w, h;
    int qFactor;
    Vector v;
    String roomName;
    DrawingPanelVector dpv;


public RoomView(RoomPController newRpc, String newRoomName) {
setPreferredSize(new Dimension(600,350));
    rpc = newRpc;
w = 0;
h = 0;
qFactor = 1;
v = new Vector();
roomName = newRoomName;
    v.add(new GraphicRectangle(0, 0, (int)(w*qFactor), (int)(h*qFactor), Color.black));
    dpv = new DrawingPanelVector(v);
    add(dpv);
    setVisible(true);
    getPreferredSize();
}

public void RepaintRoom() {
    Scanner c = new Scanner(System.in);
    v = new Vector();
    w = rpc.getRoomW(roomName);
    h = rpc.getRoomL(roomName);
    System.out.println("Room w = " + w + " Room h = " + h);
    System.out.println("Height = " + getHeight() + " Width = " + getWidth());
    if ((double)getHeight()/h < (double)getWidth()/w) qFactor = (int)((double)getHeight()/h);
    else qFactor = (int)((double)getWidth()/w);
    System.out.println("qFactor = " + qFactor);
    v.add(new GraphicRectangle(0, 0, (int)(w*qFactor), (int)(h*qFactor), Color.black));
    dpv = new DrawingPanelVector(v);
    add(dpv);
    setVisible(true);
}
}

AND，最后，DrawingPanelVector是：

public class DrawingPanelVector extends JPanel {
    // variable miembro
    private Vector v;
    // constructor
    public DrawingPanelVector(Vector va) {
        super(new FlowLayout());
        setPreferredSize(new Dimension(600,350));
        v = va;
        getPreferredSize();
    }
    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        Drawable dib;
        Iterator it;
        it = v.iterator();
        while (it.hasNext()) {
        dib = (Drawable) it.next();
        dib.draw(g);
    }
}
}

它没有做任何事情，MainPanel上没有任何内容这让我很生气，我必须在7个小时内将这些代码交给老师。

Answer 1

最初的问题，我认为是......

你打电话......

roomView = new RoomView(newropc,"Default");

哪个电话......

public RoomView(RoomPController newRpc, String newRoomName) {
    setPreferredSize(new Dimension(600,350));
    rpc = newRpc;
    w = 0;
    h = 0;
    qFactor = 1;
    v = new Vector();
    roomName = newRoomName;
    getPreferredSize();
}

这对组件没有任何补充。您的DrawingPaneVector没有添加RoomView，这意味着什么都不会被绘制......

其他

你违反了油漆链。绘制过程是一个复杂的系统，涉及许多子方法和委托。通过覆盖paint方法并且无法调用super.paint，您已经规避了整个绘画过程。

相反，您应该覆盖paintComponent，并确保致电super.paintComponent以确保paintComponent需要完成的工作完成......

@Override protected void paintComponent(Graphics g) { super.paintComponent(g); Drawable dib; Iterator it; it = v.iterator(); while (it.hasNext()) { dib = (Drawable) it.next(); dib.draw(g); } }

请查看Performing Custom Painting和Painting in AWT and Swing了解详情。

不建议使用setPreferredSize，主要问题是程序的另一部分很容易改变。相反，您应该覆盖自定义组件的getPreferredSize。

更多附加

我建议停止使用Vector，而是使用List，实例化ArrayList的实现。 Vector的唯一好处是它是synchronized，但我看不出你为什么要这样做。

我还建议您阅读Generics。这将使你的生活变得更容易，因为你不需要施放物体。

使用DrawingPanelVector和泛型的<{1}}小组的可能实施方式......

List

基本绘画代码。它不起作用

1 个答案: