Question

我尝试使用场景构建器构建一个简单的场景。但我没有制作一个main.java文件来运行代码！我无法理解错误是什么！

这是 FXMLDocumentController.java 文件：

import javafx.event.ActionEvent;
import javafx.fxml.FXML;

public class FXMLDocumentController {

    @FXML
    void btnHandle(ActionEvent event) {
    }

}

这里是fxml文件： sample.fxml

Main.java

import javafx.application.Application;
import static javafx.application.Application.launch;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.layout.Pane;
import javafx.stage.Stage;
import javafx.stage.StageStyle;

public class Main extends Application {

    @Override  
    public void start(Stage stage) throws Exception {
        Parent root = FXMLLoader.load(getClass().getResource("sample.fxml"));

        Scene scene = new Scene(root);

        stage.setScene(scene);
        stage.show();
    }

    /**
    * @param args the command line arguments
    */
    public static void main(String[] args) {
        launch(args);
    }  
}

当我运行此代码时，它显示错误并且无法构建：应用程序启动方法中的异常

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$155(LauncherImpl.java:182)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException: Location is required.
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3207)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3175)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3148)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3124)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3104)
    at javafx.fxml.FXMLLoader.load(FXMLLoader.java:3097)
    at Main.start(Main.java:15)
    at com.sun.javafx.application.LauncherImpl.lambda$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
Exception running application Main
C:\Users\Dell\Desktop\Exercise\Java\BasicXml\nbproject\build-impl.xml:1052: The following error occurred while executing this line:
C:\Users\Dell\Desktop\Exercise\Java\BasicXml\nbproject\build-impl.xml:806: Java returned: 1
BUILD FAILED (total time: 0 seconds)

Answer 1

我建议将主要的根类从Parent转移到AnchorPane：

public class Main extends Application {
  @Override  
  public void start(Stage stage) throws Exception {

    AnchorPane root = FXMLLoader.load(getClass().getResource("sample.fxml"));

    Scene scene = new Scene(root);

    stage.setScene(scene);
    stage.show();
 }

/**
* @param args the command line arguments
*/
  public static void main(String[] args) {
    launch(args);
  }  
}

如何使main.java运行由场景构建器设计的应用程序？

1 个答案: