Intermediate Java(23) - Drawing an Oval with Slider

創造新的class稱為DrawOval:

import java.awt.*;

import javax.swing.*;

public class DrawOval extends JPanel{

private int d = 10;

public void paintComponent(Graphics g){

super.paintComponent(g);

g.fillOval(10, 10, d, d); → 寬度和高度是變數d

}

public void setD(int newD){

d = (newD >= 0 ? newD : 10); → 如果newD大於0,等於這個數字,如果不是就是10

repaint(); → 重繪這個橢圓形(內建的method)

}

public Dimension getPreferredSize(){

return new Dimension(200,200);

}

public Dimension getMinimumSize(){

return getPreferredSize();

}

}