java - 将图像加载到 Java 中

Question

我刚刚开始用java编程。然而，最近我无法将图像加载到我的游戏中。

我尝试将它们加载到单独的资源包中并阅读/观看了无数教程，但似乎根本不起作用!

有人可以告诉我代码有什么问题或提供任何建议吗？任何帮助将非常感激。

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import javax.swing.ImageIcon;
import javax.swing.JFrame;

public class Main extends JFrame{

Image dbImage;
Graphics dbg;

//Variables for screen size
int
GWIDTH = 800,
GHEIGHT = 500;

//Dimension of gwidth and gheight
Dimension screenSize = new Dimension (GWIDTH, GHEIGHT);

public Main (){
//constructor to spawn window
this.setTitle ("Pond");
this.setSize(screenSize);
this.setResizable(false);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setVisible(true);
this.setBackground(Color.cyan);
this.addKeyListener(new AL ());
ImageIcon img = new ImageIcon (getClass().getResource("/resources/ninja-png.gif"));

}

 public static void main (String[] args){

 Main m = new Main ();
 }

 //Double Buffering
  @Override

   public void paint (Graphics g){

dbImage = createImage (getWidth(), getHeight());
dbg = dbImage.getGraphics ();
draw (dbg);
g.drawImage(dbImage, 0, 0, this);  

 }

 public void draw (Graphics g){
 }
 public void paintComponent (Graphics g){
 }
 //Event Listener Class
 public class AL extends KeyAdapter {
@Override
public void keyPressed (KeyEvent e){
}
@Override
public void keyReleased (KeyEvent e){
 }
 }

  } 

Answer 1

"Can someone tell me what's wrong with the code or provide any suggestions?"

1. 不要在 JFrame 等顶级容器上绘制。

2. 改为使用 JPanel 并重写其 paintComponent 方法并调用 super.paintComponent

3. @Override getPreferredSize() 在 JPanel 上绘制时，因此面板将具有首选大小。

4. 调用 frame.pack() 而不是设置大小，并且将遵循 JPanel 的首选大小。

5. 将该自定义绘画面板添加到 JFrame。

6. 您从未初始化您尝试绘制的图像。改为执行此操作。

   dbImage = new ImageIcon(getClass().getResource("/resources/stackoverflow5.png")).getImage();
   

   声明一个您从未使用过的新ImageIcon。

7. 从 Event Dispatch Thread 运行 Swing 应用程序像这样

   public static void main(String[] args) {
       SwingUtilities.invokeLater(new Runnable(){
           @Override
           public void run() {
               Main m = new Main();
           }
       });
   }
   

8. 确保您有直接在 src 中的资源包

   Project
         src
            resources
   

<小时/>

使用上面提到的所有内容完整重构源代码。

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class Main extends JFrame {

    Image dbImage;

    int GWIDTH = 800;
    int GHEIGHT = 500;

    public Main() {
        dbImage = new ImageIcon(getClass().getResource("/resources/stackoverflow5.png")).getImage();
        this.setTitle("Pond");
        add(new ImagePanel());
        this.pack();
        this.setResizable(false);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setVisible(true);
        this.setBackground(Color.cyan);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable(){
            @Override
            public void run() {
                Main m = new Main();
            }
        });
    }

    public class ImagePanel extends JPanel {

        @Override
        public void paintComponent(Graphics g) {
            super.paintComponent(g);

            g.drawImage(dbImage, 0, 0, GWIDTH, GHEIGHT, this);
        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(GWIDTH, GHEIGHT);
        }
    }
}