在背景颜色的jpanel上绘制一个2D图形形状

Question

我有8个背景颜色的jpanels，我试图在它上面绘制一个矩形，但它显示在它下面，我不能把它放在顶部

以下是初始化JPanel

的代码

tempPanel = new JPanel();
        tempPanel.setBackground(Color.black);
        tempPanel.setOpaque(true);
        tempPanel.setLayout(null);
        panel.add(tempPanel);
        tempPanel.setBounds(195 + insets.left, 155 + insets.top,
                main.getLanes().get(5).getDistance()*5, 20);
        if (!added)
            lanes.add(tempPanel);

和绘制矩形的代码;它位于一个扩展Jpanel和inisde paintComponents的类中：

super.paintComponent(g);
        Graphics2D g2d = (Graphics2D) g;
        drawLanes();
        int i, j;
        ArrayList<Lane> lanes2= new ArrayList<Lane>();
        ArrayList<Car> cars= new ArrayList<Car>();
        for(int counter = 0; counter < 10; counter ++) {
            lanes2 = main.getLanes();
            for( i = 0; i< lanes.size(); i++) {
                lanes.get(i).removeAll();
                cars = lanes2.get(i).getCars();
                for ( j = 0; j < cars.size(); j++) {
                    Insets insets = lanes.get(i).getInsets();
                    g2d.setColor(Color.red);
                    g2d.draw(new Rectangle(lanes.get(i).getLocation().x + 5*(lanes2.get(i).getDistance() - cars.get(j).getCurrent_pos()), lanes.get(i).getLocation().y,
                            cars.get(j).getCar_size()*5, lanes.get(i).getHeight()));
                    JLabel temp = new JLabel("Car");
                    temp.setForeground(Color.red);
                    temp.setBounds(insets.left + 5*(lanes2.get(i).getDistance() - cars.get(j).getCurrent_pos()) , insets.top,
                            cars.get(j).getCar_size()*5, lanes.get(i).getHeight());
                    lanes.get(i).add(temp);
                }
            }
        }

感谢adavnce