如何为我的JavaFX程序加载FXML URL

Question

我目前正在学习JavaFX的Jenkov教程。他写了以下代码

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Scene;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
import java.net.URL;
public class FXMLExample extends Application{
public static void main(String[] args) {
launch(args);
}
@Override
public void start(Stage primaryStage) throws Exception {
FXMLLoader loader = new FXMLLoader();
loader.setLocation(new URL("file:///C:/data/hello-world.fxml"));
VBox vbox = loader.<VBox>load();
Scene scene = new Scene(vbox);
primaryStage.setScene(scene);
primaryStage.show();
}
}

这是他写的我的版本：

package sample;
import javafx.application.Application;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
import java.net.URL;
//import java.awt.*;
public class Main extends Application {
// The start method takes a single parameter of type stage.
// The stage is where all the visual parts of the application are displayed
// The stage is created
@Override
public void start(Stage primaryStage) throws Exception{
FXMLLoader loader = new FXMLLoader();
loader.setLocation(new URL("home/amnar/IdeaProjects/mockUI/src/sample/sample.fxml"));
VBox vbox = loader.<VBox>load();
Scene scene = new Scene(vbox);
primaryStage.setTitle("My first JavaFX app");
primaryStage.setScene(scene);
primaryStage.show();
}

public static void main(String[] args) {
launch(args);
}
}

现在，当我尝试运行这个时，我会收到以下堆栈跟踪的错误：

Gtk-Message: 13:44:10.402: Failed to load module "canberra-gtk-module"
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$154(LauncherImpl.java:182)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.net.MalformedURLException: no protocol: homeamnarIdeaProjectsmockUIsrcsamplesample.fxml
at java.net.URL.<init>(URL.java:593)
at java.net.URL.<init>(URL.java:490)
at java.net.URL.<init>(URL.java:439)
at sample.Main.start(Main.java:24)
at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$161(LauncherImpl.java:863)
at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$174(PlatformImpl.java:326)
at com.sun.javafx.application.PlatformImpl.lambda$null$172(PlatformImpl.java:295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.application.PlatformImpl.lambda$runLater$173(PlatformImpl.java:294)
at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
at com.sun.glass.ui.gtk.GtkApplication._runLoop(Native Method)
at com.sun.glass.ui.gtk.GtkApplication.lambda$null$48(GtkApplication.java:139)
... 1 more
Exception running application sample.Main
Process finished with exit code 1

我知道gtk错误，我不确定它是否导致了这个问题。我在我的机器上运行ubuntu 18.04.01 LTS，将buggie作为桌面环境。我发现gtk错误是由一些东西引起的，默认安装是32位，而我的机器是64位。我试图解决这个问题，但没有成功。尽管如此，当我尝试在不必使用FXML文件的情况下运行JavaFX示例时，即使错误仍然存在，它也能正常工作。

我在这里错过了什么？我是否必须做一些不同的事情，因为我运行的是linux，而这个例子似乎是在windows上运行的？我看到了导入FXML的各种其他方法，例如使用getClass((。。。等等。同样，我会得到这个巨大的堆栈跟踪，但我不理解。看来跟踪的关键部分是：

Caused by: java.net.MalformedURLException: no protocol: homeamnarIdeaProjectsmockUIsrcsamplesample.fxml

因此，我认为我需要重新格式化URL，我不知道该怎么办

谢谢！

Answer 1

您已经正确地认识到了您的问题。Java的URL类需要有指定的协议。试试这个：

loader.setLocation(new URL("file:///home/amnar/IdeaProjects/mockUI/src/sample/sample.fxml"));