java - 无法对非静态字段 JAVAFX 进行静态引用

Question

我在学习 javafx 教程时遇到了一些麻烦，即使我使用与教程完全相同的代码，我也收到错误“无法对非静态字段进行静态引用”，我尝试在这里搜索关于堆栈溢出，但我找不到类似这里发生的事情。这是我的代码:

    package projeto;


import java.io.IOException;

import ch.makery.address.MainApp;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Scene;
import javafx.scene.layout.AnchorPane;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;

public class MainApp extends Application {

    private Stage primaryStage;
    private BorderPane rootLayout;

    @Override
    public void start(Stage primaryStage) {
        this.primaryStage = primaryStage;
        this.primaryStage.setTitle("CineTudo");

        initRootLayout();

        showFilmeOverview();
    }

    public void initRootLayout(){
        try {
            //Carrega o layout root do arquivo fxml
            FXMLLoader loader = new FXMLLoader(MainApp.class.getResource("resources/RootLayout.fxml"));
            rootLayout = (BorderPane) loader.load();
            Scene cena = new Scene(rootLayout);
            primaryStage.setScene(cena);
            primaryStage.show();

        } catch(IOException e) {
            e.printStackTrace();

       }
   }
        public static void showFilmeOverview() {        
        try {
            FXMLLoader loader = new FXMLLoader();
            loader.setLocation((MainApp.class.getResource("resources/FilmeOverview.fxml")));
            AnchorPane filmeOverview = (AnchorPane) loader.load();
            rootLayout.setCenter(filmeOverview);
        }catch (IOException e){

            e.printStackTrace();
        }

     }
public Stage getPrimaryStage() {
            return primaryStage;
     }


public static void main(String[] args) {

    launch(args);
}

}

<小时/>

这是教程的代码:

    package ch.makery.address;

import java.io.IOException;

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Scene;
import javafx.scene.layout.AnchorPane;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;

public class MainApp extends Application {

    private Stage primaryStage;
    private BorderPane rootLayout;

    @Override
    public void start(Stage primaryStage) {
        this.primaryStage = primaryStage;
        this.primaryStage.setTitle("AddressApp");

        initRootLayout();

        showPersonOverview();
    }

    /**
     * Initializes the root layout.
     */
    public void initRootLayout() {
        try {
            // Load root layout from fxml file.
            FXMLLoader loader = new FXMLLoader();
            loader.setLocation(MainApp.class.getResource("view/RootLayout.fxml"));
            rootLayout = (BorderPane) loader.load();

            // Show the scene containing the root layout.
            Scene scene = new Scene(rootLayout);
            primaryStage.setScene(scene);
            primaryStage.show();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * Shows the person overview inside the root layout.
     */
    public void showPersonOverview() {
        try {
            // Load person overview.
            FXMLLoader loader = new FXMLLoader();
            loader.setLocation(MainApp.class.getResource("view/PersonOverview.fxml"));
            AnchorPane personOverview = (AnchorPane) loader.load();

            // Set person overview into the center of root layout.
            rootLayout.setCenter(personOverview);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * Returns the main stage.
     * @return
     */
    public Stage getPrimaryStage() {
        return primaryStage;
    }

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

<小时/>

这是我的错误:

javafx.fxml.LoadException: BorderPane is not a valid type.
/C:/Users/Eduardo%20Abreu/Documents/Eclipse-Workspace/UnifacsProjeto/bin/projeto/resources/RootLayout.fxml

    at javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2597)
    at javafx.fxml.FXMLLoader.createElement(FXMLLoader.java:2774)
    at javafx.fxml.FXMLLoader.processStartElement(FXMLLoader.java:2704)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2527)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2441)
    at javafx.fxml.FXMLLoader.load(FXMLLoader.java:2409)
    at projeto.MainApp.initRootLayout(MainApp.java:33)
    at projeto.MainApp.start(MainApp.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.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$147(WinApplication.java:177)
    at java.lang.Thread.run(Thread.java:748)
Exception in Application start method
java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:389)
    at com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:328)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at sun.launcher.LauncherHelper$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.lang.Error: Unresolved compilation problem: 
    Cannot make a static reference to the non-static field rootLayout

    at projeto.MainApp.showFilmeOverview(MainApp.java:48)
    at projeto.MainApp.start(MainApp.java:26)
    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.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$147(WinApplication.java:177)
    ... 1 more
Exception running application projeto.MainApp

Answer 1

不一样;)

在您的代码中，方法 showFilmeOverview 是静态，您可以在其中访问私有(private)的 rootLayout。这是错误的。

您需要将方法 showFilmeOverview 更改为非静态。