我真的很困惑如何通过将它作为参数传递来在 jpanel 上画一个圆圈..
public class test extends JPanel{
public test(JPanel jpanelcomponent) {
}
@Override
protected void paintComponent(Graphics g) {
// TODO Auto-generated method stub
super.paintComponent(g);
int width = getWidth()/2;
int height = getHeight()/2;
g.fillOval(5, 5, width, height);
}
}
我认为更好的设计会让您将通过Graphic覆盖paintComponent(..)a获得的 s 对象传递JPanel给将绘制到图形对象的类
这是我做的一个例子：
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class Test {
public Test() {
initComponents();
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
new Test();
}
});
}
private void initComponents() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
final DrawingClass dc = new DrawingClass();
JPanel testPanel = new JPanel() {
@Override
protected void paintComponent(Graphics grphcs) {
super.paintComponent(grphcs);
Graphics2D g2d = (Graphics2D) grphcs;
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
dc.draw(g2d, getWidth(), getHeight());
}
@Override
public Dimension getPreferredSize() {
return new Dimension(300, 300);
}
};
frame.add(testPanel);
frame.pack();
frame.setVisible(true);
}
}
class DrawingClass {
public void draw(Graphics2D g2d, int w, int h) {
g2d.setColor(Color.BLACK);
g2d.fillOval(5, 5, w / 2, h / 2);
}
}