无法调用"java.net.URL.toExternalForm()“，因为”位置“为空Java Graphics2D
无法调用"java.net.URL.toExternalForm()“，因为”位置“为空Java Graphics2D
提问于 2022-11-23 16:07:14
我有问题，检测我的图像，它总是说，它的位置，它的零码，做什么。我需要叫这个图像。我已经试过很多事情了，但还是弄不清楚。我尝试过在资源包中，在另一个包中，使用完整的路径，但是如果。
/*
* Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license
* Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Class.java to edit this template
*/
package game.objeto;
import java.awt.GradientPaint;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.geom.AffineTransform;
import java.net.URL;
import javax.swing.ImageIcon;
/**
*
* @author sousa
*/
public class Player {
public Player(){
this.image=new ImageIcon(getClass().getResource("resources/plane.png")).getImage();
this.image_speed=new ImageIcon(getClass().getResource("resources/plane_speed.png")).getImage();
}
public static final double PLAYER_SIZE=64;
private double x;
private double y;
private float angle=0f;
private final Image image;
private final Image image_speed;
public void changeAngle(float angle){
if(angle<0){
angle=359;
}else if(angle>359){
angle=0;
}
this.angle=angle;
}
public void draw(Graphics2D g2){
AffineTransform oldTransform = g2.getTransform();
g2.translate(x, y);
g2.drawImage(image, 0,0,null);
g2.setTransform(oldTransform);
}
public double getX(){
return x;
}
public double getY(){
return y;
}
public float getAngle(){
return angle;
}
}而错误是
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException: Cannot invoke "java.net.URL.toExternalForm()" because "location" is null
at java.desktop/javax.swing.ImageIcon.<init>(ImageIcon.java:232)
at game.objeto.Player.<init>(Player.java:22)
at game.componentes.PanelGame.initObjectGame(PanelGame.java:74)
at game.componentes.PanelGame.start(PanelGame.java:69)
at game.main.Main$1.windowOpened(Main.java:35)
at java.desktop/java.awt.Window.processWindowEvent(Window.java:2082)
at java.desktop/javax.swing.JFrame.processWindowEvent(JFrame.java:298)
at java.desktop/java.awt.Window.processEvent(Window.java:2044)
at java.desktop/java.awt.Component.dispatchEventImpl(Component.java:4991)
at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2324)
at java.desktop/java.awt.Window.dispatchEventImpl(Window.java:2780)
at java.desktop/java.awt.Component.dispatchEvent(Component.java:4823)
at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:775)
at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:720)
at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:714)
at java.base/java.security.AccessController.doPrivileged(AccessController.java:399)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:97)
at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:747)
at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:745)
at java.base/java.security.AccessController.doPrivileged(AccessController.java:399)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:744)
at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203)
at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124)
at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113)
at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109)
at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:90)
------------------------------------------------------------------------Thx预先
回答 1
Stack Overflow用户
发布于 2022-11-23 16:15:31
这是因为您使用.getClass()进行非静态引用来获取资源URL。您必须使用使用Player.class的静态引用。此外，如果/resources已定义为项目中的源文件夹，则不需要将图像路径与该源文件夹路径放在前面。
试试这个：
public Player(){
this.image = (new ImageIcon(Player.class.getResource("/plane.png")).getImage());
this.image_speed = (new ImageIcon(Player.class.getResource("/plane_speed.png")).getImage());
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/74549838
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