以下代码段之间有什么区别?

问题描述 投票:0回答:1

这些代码段中的一个有效,而另一个无效,但我不知道为什么。我试过调试一个无效的程序。代码的本质是相同的,我将其复制粘贴。可行的程序来自一个稍大的程序,该程序最初显示两个阶段。教授希望我们扩展原始程序的一部分,因此我认为最好创建一个新项目,以使其更易于阅读和上传。问题是新的不起作用。

        This One Works

   ***int num1 = (int) (Math.random()*61);
   int num2 = (int) (Math.random()*61);
   int num3 = (int) (Math.random()*61);

   Stage Tiles = new Stage();
   Tiles.setTitle("Tiles");
   FlowPane tilePane = new FlowPane();
   System.out.println(num1 +" " + num2 + " " + num3);

   ImageView image1 = new ImageView(String.valueOf(num1)+".png");
   ImageView image2 = new ImageView(String.valueOf(num2)+".png");
   ImageView image3 = new ImageView(String.valueOf(num3)+".png");

   tilePane.getChildren().addAll(image1,image2,image3);
   Scene secondScene = new Scene(tilePane);
   Tiles.setScene(secondScene);
   Tiles.show();

} ***

           This One Does Not Work

public class Case_lab6a extends Application

{@Override

public void start(Stage main)
{
   int num1 = (int) (Math.random()*61);
   int num2 = (int) (Math.random()*61);
   int num3 = (int) (Math.random()*61);


   main.setTitle("Tiles v2");
   FlowPane tilePane = new FlowPane();
   System.out.println(num1 +" " + num2 + " " + num3);

   ImageView image1 = new ImageView(String.valueOf(num1)+".png");
   ImageView image2 = new ImageView(String.valueOf(num2)+".png");
   ImageView image3 = new ImageView(String.valueOf(num3)+".png");



   tilePane.getChildren().addAll(image1,image2,image3);
   Scene secondScene = new Scene(tilePane);
   main.setScene(secondScene);
   main.show();
}

基于错误,我得到此问题与编译器无法识别图像有关。我知道我的结构方式很奇怪,并且可能有更好的方法,但是我有61张图像全部存储在src文件中。

编辑:非功能性细分市场的进口:

import javafx.application.Application;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.image.ImageView;
import javafx.scene.layout.FlowPane;
import javafx.scene.layout.GridPane;
import javafx.stage.Stage;

该工作部门的进口:

import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.image.ImageView;
import static javafx.scene.layout.BackgroundPosition.CENTER;
import javafx.scene.layout.FlowPane;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.HBox;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
import javafx.stage.Stage;

非功能程序的输出:

23 35 22
Exception in Application start method
java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:389)
    at com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:328)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at sun.launcher.LauncherHelper$FXHelper.main(LauncherHelper.java:767)
Caused by: java.lang.RuntimeException: Exception in Application start method
    at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:917)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$155(LauncherImpl.java:182)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.IllegalArgumentException: Invalid URL: Invalid URL or resource not found
    at javafx.scene.image.Image.validateUrl(Image.java:1118)
    at javafx.scene.image.Image.<init>(Image.java:620)
    at javafx.scene.image.ImageView.<init>(ImageView.java:166)
    at lab6a.Case_lab6a.start(Case_lab6a.java:35)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$162(LauncherImpl.java:863)
    at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$175(PlatformImpl.java:326)
    at com.sun.javafx.application.PlatformImpl.lambda$null$173(PlatformImpl.java:295)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$174(PlatformImpl.java:294)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
    ... 1 more
Caused by: java.lang.IllegalArgumentException: Invalid URL or resource not found
    at javafx.scene.image.Image.validateUrl(Image.java:1110)
    ... 12 more
Exception running application lab6a.Case_lab6a
C:\Users\Kindness\AppData\Local\NetBeans\Cache\8.2\executor-snippets\run.xml:53: Java returned: 1
BUILD FAILED (total time: 1 second)
java image javafx
1个回答
0
投票
Stage Tiles = new Stage();

[而另一个(您说的那个不起作用)希望您在调用Stage方法时传递start()对象。

[Aside:Tiles变量应为tiles以遵循Java命名约定。类名以大写字母开头,变量应为camelCase。]

您说错误与图像有关。包括确切的错误消息(以及完整的堆栈跟踪,如果可能)将对您有所帮助。

您应注意的一件事是,当您使用Math.random()时,它可能会返回0。您的图片编号从0到60?如果没有,也许它会时不时地(随机)找不到图像文件。

顺便说一句,要生成随机整数,最好使用:

Random rand = new Random(); int num1 = rand.nextInt(61); int num2 = rand.nextInt(61); int num3 = rand.nextInt(61);

此外,您可以将String.valueOf(num1)+".png"简化为num1 + ".png"。整数附加到字符串后会自动转换为字符串。您已经在System.out.println(num1 + " " + num2 + " " + num3)行中完成了此操作。

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