我正在尝试在 JFrame 内的 JPanel 内绘制一个矩形。我想使用 PaintComponents(Graphics g) 方法并覆盖它,但由于某种原因,矩形没有像我希望的那样出现在 JPanel 中。任何帮助,将不胜感激。
public class RectangleFrame extends JFrame implements ActionListener {
JPanel buttonPanel;
JButton saveImage;
JButton clearImage;
JCheckBox intersections;
JCheckBox union;
JPanel drawingArea;
public RectangleFrame()
{
super();
setTitle("Rectangles");
setSize(600,600);
setResizable(false);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
buttonPanel = new JPanel();
buttonPanel.setBorder(BorderFactory.createLineBorder(Color.black));
this.add(buttonPanel, BorderLayout.SOUTH);
intersections = new JCheckBox("Draw Intersections");
buttonPanel.add(intersections);
union = new JCheckBox("Draw Union");
buttonPanel.add(union);
saveImage = new JButton("Save Image");
saveImage.setMargin(new Insets(0,0,0,0));
buttonPanel.add(saveImage);
clearImage = new JButton("Clear Image");
clearImage.setMargin(new Insets(0,0,0,0));
buttonPanel.add(clearImage);
drawingArea = new JPanel();
drawingArea.setBorder(BorderFactory.createLineBorder(Color.blue));
this.add(drawingArea, BorderLayout.CENTER);
}
}
class RectanglePanel extends JPanel
{
public RectanglePanel()
{
super();
}
@Override
public void paintComponent(Graphics g)
{
super.paintComponent(g);
g.setColor(Color.BLUE);
g.fillRect(25,25,100,30);
}
}
这是我的主要方法,它位于一个单独的类中:
public class SwingRectangle
{
/**
* @param args
*/
public static void main(String[] args)
{
// TODO Auto-generated method stub
RectangleFrame frame = new RectangleFrame();
RectanglePanel panel = new RectanglePanel();
frame.setVisible(true);
}
}
最佳答案
您没有将 RectanglePanel
添加到框架中。
drawingArea = new JPanel();
应该是
drawingArea = new RectanglePanel();
其他要点:
- 您仍然需要重写
paintComponent
而不是 @David 建议的paintComponents
,所以给他+1 - 在
SwingRectangle
中创建的面板未使用
关于java - 如何在 JPanel 中绘制矩形,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/22105489/