我第一次使用JPanel并在JPanel上绘制基本形状。
我为这样的形状编写了代码：
public class Shape extends JPanel{
int x,y;
public Shape(int x, int y){
this.x = x;
this.y = y;
}
public void paint(Graphics g){
super.paint(g);
g.setColor(Color.black);
g.drawRect(x, y, 20, 20);
}
}
我有另一个类，我将在其中使用这个形状。它扩展了JFrame并实现了MouseListener。在这个JFrame上，我放置了JPanel，它被简单地称为“面板”。
我有方法，读取鼠标位置，并在“面板”上绘制形状。
public void mouseClicked(MouseEvent e){
Shape shape = new Shape(e.getX(),e.getY());
panel.add(shape);
panel.revalidate();
panel.repaint();
}
问题是它没有在我的鼠标所在的坐标上绘制形状。它只是在上面的面板上绘制，然后将它们画成一条线。
谢谢你的回答。
public class ShapesPanel extends JPanel {
private java.util.List shapesList ;
/**
* Constructs <code>ShapesPanel</code>
*/
public ShapesPanel() {
shapesList = new java.util.ArrayList() ;
this.addMouseListener(new MouseClickListener()) ;
}
/**
* Creates a shape
* @param bounds
* @return
*/
private Shape createShape( Rectangle bounds ) {
Shape shape = new Ellipse2D.Double(bounds.x, bounds.y, bounds.width, bounds.height );
/*
To use the following shapes, you need to have java shapes library, which can
be downloaded from <a href="http://wwww.jshapes.com">Java Shapes Library</a>
*/
/*
// To create star shape
Shape shape = new Star( bounds, 50, Star.STAR_8_POINTS );
// To create triangle shape
Shape shape = new Triangle( bounds, Triangle.UP );
// To create diamond shape
Shape shape = new Diamond( bounds );
// To create Parallelogram shape
Shape shape = new Parallelogram( bounds );
*/
return shape ;
}
/**
* MouseClickListener
*/
private class MouseClickListener extends MouseAdapter {
@Override
public void mouseClicked(MouseEvent e) {
Point pt = e.getPoint();
Dimension size = new Dimension(100, 100 );
Rectangle bounds = new Rectangle(pt.x, pt.y, size.width, size.height );
Shape shape = createShape(bounds);
shapesList.add( shape );
repaint();
}
}
/**
* Paints the component
* @param g
*/
protected void paintComponent(Graphics g) {
Graphics2D g2 = (Graphics2D) g;
Rectangle bounds = new Rectangle(0,0,getWidth(), getHeight() );
g2.setPaint( Color.white );
g2.fill( bounds );
for (Iterator iterator = shapesList.iterator(); iterator.hasNext(); ) {
Shape shape = (Shape) iterator.next();
g2.setPaint( Color.cyan );
g2.fill( shape );
g2.setPaint( Color.black );
g2.draw( shape );
}
}
/**
* Driver
* @param args
*/
public static void main(String[] args) {
JFrame frame = new JFrame("Draw Shapes") ;
frame.getContentPane().add( new ShapesPanel() );
frame.setSize(600, 600);
frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE);
frame.setVisible( true );
}
}
希望这有助于在面板中绘制java形状。
