Question

用户点击一个位置并在另一个位置发布。我使用点击开始的位置和结束的位置来制作两个坐标。这就是我想要得到的矩形的宽度和高度，以便满足drawRect（）方法的所有参数。我想让他们制作的矩形出现在屏幕上。它显示宽度和高度，但不创建矩形。

    import java.awt.*; 
    import java.awt.event.*;
    import java.applet.*;

    import javax.swing.Timer;

    @SuppressWarnings("serial")
    public class PracticeClass extends Applet implements MouseListener, ActionListener, KeyListener
    {
       int x, y, velX, velY, Width, Height, x2, y2;
       String tracer, tracer2, tracer3;
       Timer tm = new Timer(4, this);

       public PracticeClass()
       { 
          tm.start();
          setFocusable(true);
          setSize(900, 900);
          setFocusTraversalKeysEnabled(false);
          addKeyListener(this);
          addMouseListener(this);
       } 
       public void mousePressed(MouseEvent e){} 
       public void mouseClicked(MouseEvent e)
       {
           x = e.getX(); 
           y = e.getY(); 
           tracer = " x = " + x + " y = " + y;
           // repaint the applet// 
           repaint(); 
       } 
       public void mouseEntered(MouseEvent e){} 
       public void mouseExited(MouseEvent e){} 
       public void mouseReleased(MouseEvent e)
       {
           int x2 = e.getX();
           int y2 = e.getY();
           int Width = x2 - x;
           int Height = y2 - y;
           tracer2 = "Width = " + Width + " Height = " + Height;
           tracer3 = "X2 = " + x2 + " Y2 = " + y2;
           repaint();
       } 
       // paint method 
       public void paint(Graphics g){ 
            g.drawString(tracer, 0, 20);
            g.drawString(tracer2,  0, 40);
            g.drawString(tracer3,  0,  60);
            g.drawRect(x,y, Width, Height); 
            g.setColor(Color.BLUE);
       } 

       public void actionPerformed(ActionEvent e)
       {
           if (x < 0)
           {
               velX = 0;
               x = 0;
           }
           if (x > 470)
           {
               velX = 0;
               x = 470;
           }
           if (y < 0)
           {
               velY = 0;
               y = 0;
           }
           if (y > 470)
           {
               velY = 0;
               y = 470;
           }
           x = x + velX;
           y = y + velY;
           repaint();
       }

       public void keyPressed(KeyEvent e)
        {
            int c = e.getKeyCode();

            if (c == KeyEvent.VK_LEFT)
            {
                velX = -1;
            }
            if (c == KeyEvent.VK_RIGHT)
            {
                velX = 1;
            }
            if (c == KeyEvent.VK_UP)
            {
                velY = -1;
            }
            if (c == KeyEvent.VK_DOWN)
            {
                velY = 1;
            }
            repaint();
        } 

       public void keyTyped(KeyEvent e){}
       public void keyReleased(KeyEvent e)
       {
          int c = e.getKeyCode();

          if ((c == KeyEvent.VK_LEFT) || (c == KeyEvent.VK_RIGHT))
          {
              velX = 0;
          }

          if ((c == KeyEvent.VK_UP) || (c == KeyEvent.VK_DOWN))
          {
              velY = 0;
          }
       }
  }

Answer 1

g.drawRect(x, y, Width, Height)

在重新放入mouseReleased函数之前把它放好

你已经做了所有艰苦的工作，哈哈

使用户制作的矩形出现在屏幕上

1 个答案: