小白求助!请问怎么用Graphics类画多边形??要用drawLine 这个方法!
具体是这样:先自己画一条线,再在其他地方单击,使其自动生成一条(和前一条线的释放点连在一起的)线,如此重复,最后双击,形成闭合多边形。救救孩子吧,要交作业了!!!
能给一个程序最好了!!
public class Test extends JPanel { /** * */ private static final long serialVersionUID = 1L; static class Cell { int x; int y; public int getX() { return x; } public int getY() { return y; } public Cell(int x, int y) { super(); this.x = x; this.y = y; } } private static List<Cell> cells = new ArrayList<>(); @Override public void paint(Graphics g) { g.setColor(Color.RED); int[] xPoints = new int[cells.size()]; int[] yPoints = new int[cells.size()]; for (int i = 0; i < cells.size(); i++) { xPoints[i] = cells.get(i).getX(); yPoints[i] = cells.get(i).getY(); } g.fillPolygon(xPoints, yPoints, cells.size()); if(cells.size() < 1) { g.setColor(Color.WHITE); g.fillRect(0, 0, 400, 400); } } static LocalDateTime prevClickTime = LocalDateTime.now(); static LocalDateTime curClickTime = null; MouseAdapter mouseAdapter = new MouseAdapter() { public void mouseClicked(MouseEvent e) { Test.this.repaint(); curClickTime = LocalDateTime.now(); cells.add(new Cell(e.getX()-8, e.getY()-30)); Duration duration = Duration.between(prevClickTime, curClickTime); int nano = duration.getNano(); if(nano <= Duration.ofMillis(180).getNano()) { System.out.println("clear"); cells.clear(); } prevClickTime = curClickTime; }; }; private void start() { JFrame jframe = new JFrame(); jframe.setVisible(true); jframe.setSize(400, 400); jframe.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); jframe.add(this); jframe.addMouseListener(mouseAdapter); } public static void main(String[] args) { new Test().start(); } }