试图从 Java 调用 JavaFX 应用程序... NoSuchMethodException

问题描述

我有一个主类，它应该调用 JavaFX 应用程序 (SimpleSun) 从用户那里获取信息.目前我创建了一个 JavaFX 类的对象并启动它，但这似乎不起作用.有人看到我工作中的错误吗?

I have a main class which should call a JavaFX application (SimpleSun) to get Information from the user. Currently I create an Object of the JavaFX class and start it, but that doesn't seem to work. Does someone see the mistake in my work?

这是我的代码和异常:Main.java:

Here's my code and exception:Main.java:

package ch.i4ds.stix.sim;

import ch.i4ds.stix.sim.grid.config.Configuration;
import ch.i4ds.stix.sim.grid.config.ConfigurationFromFile;


    public class Main{
    Configuration config;
    public static void main(String[] args) {
        ConfigurationFromFile config = new ConfigurationFromFile();
        SimpleSun ss = new SimpleSun(config);
        ss.show();
    }
}

SimpleSun.java:

SimpleSun.java:

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Scene;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;
import ch.i4ds.stix.sim.grid.config.Configuration;
import ch.i4ds.stix.sim.grid.config.ConfigurationFromFile;

public class SimpleSun extends Application{

    private Stage primaryStage;
    Configuration configuration;

    public SimpleSun(ConfigurationFromFile config) {
        this.configuration = config;
    }

    @Override
    public void start(Stage primaryStage) throws Exception {
        this.primaryStage = primaryStage;
        this.primaryStage.setTitle("Simple Sun - Alpha");
        System.out.println("Test");
        try {
            // Load the root layout from the fxml file
            FXMLLoader loader = new FXMLLoader(
                    Main.class.getResource("view/RootLayout.fxml"));
            BorderPane rootLayout = (BorderPane) loader.load();
            Scene scene = new Scene(rootLayout);
            primaryStage.setScene(scene);
            primaryStage.show();
        } catch (IOException e) {
            // Exception gets thrown if the fxml file could not be loaded
            e.printStackTrace();
        }
    }

    public void show(){
        launch();
    }

}

异常:

Exception in Application constructor
Exception in thread "main" java.lang.RuntimeException: Unable to construct Application instance: class ch.i4ds.stix.sim.SimpleSun
    at com.sun.javafx.application.LauncherImpl.launchApplication1(Unknown Source)
    at com.sun.javafx.application.LauncherImpl.access$000(Unknown Source)
    at com.sun.javafx.application.LauncherImpl$1.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NoSuchMethodException: ch.i4ds.stix.sim.SimpleSun.<init>()
    at java.lang.Class.getConstructor0(Unknown Source)
    at java.lang.Class.getConstructor(Unknown Source)
    ... 4 more

推荐答案

在扩展应用程序时，您必须提供一个不带参数的构造函数.所以你可以这样做:

You must provide a constructor with no arguments when you extend application. So you could do something like:

public class SimpleSun extends Application {

    private Stage primaryStage;
    Configuration configuration;

    public SimpleSun() {
        this.configuration = Main.getConfig();
    }
    //...

在你的 Main 类中:

public static Configuration getConfig() { return new ConfigurationFromFile(); }

或者，您可以使用 launch(args) 将 String 参数传递给类，并使用 将它们返回到 SimpleSun 类中getParameters().

Alternatively you can pass String parameters to the class with launch(args) and get them back in the SimpleSun class with getParameters().

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