我想在 JPanel(Java) 上获取 ImageIcon 的当前位置

Question

我想获取图像的坐标，以便可以更改 JPanel 相对于坐标的背景颜色。这是我到目前为止所拥有的。该代码允许用户向上、向下、向右和向左移动箭头，因此如果箭头位于第一象限，则背景应为红色，如果箭头移动到第二象限，则背景颜色变为绿色，依此类推

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class DirectionPanel extends JPanel
{
   private final int X = 200;
   private Point point = null;

   private final int WIDTH = 400, HEIGHT = 200;
   private final int JUMP = 10;  // increment for image movement

   private final int IMAGE_SIZE = 31;

   private ImageIcon up, down, right, left, currentImage;
   private int x, y;

   //-----------------------------------------------------------------
   //  Constructor: Sets up this panel and loads the images.
   //-----------------------------------------------------------------
   public DirectionPanel()
   {
      addKeyListener (new DirectionListener());

      x = WIDTH / 2;
      y = HEIGHT / 2;

      up = new ImageIcon ("arrowUp.gif");
      down = new ImageIcon ("arrowDown.gif");
      left = new ImageIcon ("arrowLeft.gif");
      right = new ImageIcon ("arrowRight.gif");

      currentImage = right;

      setBackground (Color.black);
      setPreferredSize (new Dimension(WIDTH, HEIGHT));
      setFocusable(true);
   }

   //-----------------------------------------------------------------
   //  Draws the image in the current location.
   //-----------------------------------------------------------------
   public void paintComponent (Graphics page)
   {
      super.paintComponent (page);
      currentImage.paintIcon (this, page, x, y);
   }

   //*****************************************************************
   //  Represents the listener for keyboard activity.
   //*****************************************************************
   private class DirectionListener implements KeyListener
   {
      //--------------------------------------------------------------
      //  Responds to the user pressing arrow keys by adjusting the
      //  image and image location accordingly.
      //--------------------------------------------------------------
      public void keyPressed (KeyEvent event)
      {
         switch (event.getKeyCode())
         {
            case KeyEvent.VK_UP:
                currentImage = up;
                y -= JUMP;
                break;
            case KeyEvent.VK_DOWN:
                currentImage = down;
                y += JUMP;
                break;
            case KeyEvent.VK_LEFT:
                currentImage = left;
                x -= JUMP;
                break;
            case KeyEvent.VK_RIGHT:
                currentImage = right;
                x += JUMP;
                break;
         }

         point = ???????

         if(point.x < 200 && point.y < 100)
         {
            setBackground(Color.red);
         }
         else if(point.x < 200 && point.y > 100)
         {
            setBackground(Color.green);
         }
         else if(point.y > 100 && point.x > 200)
         {
            setBackground(Color.cyan);
         }
         else if(point.y < 100 && point.x > 200)
         {
            setBackground(Color.yellow);
         }

         repaint();
      }

      //--------------------------------------------------------------
      //  Provide empty definitions for unused event methods.
      //--------------------------------------------------------------
      public void keyTyped (KeyEvent event) {}
      public void keyReleased (KeyEvent event) {}
   }
}

Answer 1

您使用变量：“x”和“y”来绘制图像，因此这些变量将是您的图像在 JPanel 中的坐标。

您可以将点设置为：

    point = new Point(x, y);

现在，当您更新“x”和“y”时，点也将更新，背景将根据您的规范绘制。

希望对你有帮助！