英文:
Can't seem to get my JavaFX to run successfully. I'm using JRE 10.0.2 as required for my class
问题
在运行代码时，除了以下错误之外，没有其他迹象表明代码有问题。
```none
在Application启动方法中的异常
java.lang.reflect.InvocationTargetException
在java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
在java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
在java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
在java.base/java.lang.reflect.Method.invoke(Unknown Source)
在javafx.graphics/com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(Unknown Source)
在javafx.graphics/com.sun.javafx.application.LauncherImpl.launchApplication(Unknown Source)
在java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
在java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
在java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
在java.base/java.lang.reflect.Method.invoke(Unknown Source)
在java.base/sun.launcher.LauncherHelper$FXHelper.main(Unknown Source)
由于：java.lang.RuntimeException: 在Application启动方法中的异常
在javafx.graphics/com.sun.javafx.application.LauncherImpl.launchApplication1(Unknown Source)
在javafx.graphics/com.sun.javafx.application.LauncherImpl.lambda$launchApplication$2(Unknown Source)
在java.base/java.lang.Thread.run(Unknown Source)
由于：java.lang.IllegalArgumentException: StackPane@4df22f20 已经位于场景图中，不能设置为根
在javafx.graphics/javafx.scene.Scene$8.invalidated(Unknown Source)
在javafx.base/javafx.beans.property.ObjectPropertyBase.markInvalid(Unknown Source)
在javafx.base/javafx.beans.property.ObjectPropertyBase.set(Unknown Source)
在javafx.graphics/javafx.scene.Scene.setRoot(Unknown Source)
在javafx.graphics/javafx.scene.Scene.<init>(Unknown Source)
在javafx.graphics/javafx.scene.Scene.<init>(Unknown Source)
在application.Shapes.start(Shapes.java:64)
在javafx.graphics/com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$9(Unknown Source)
在javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runAndWait$11(Unknown Source)
在javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$9(Unknown Source)
在java.base/java.security.AccessController.doPrivileged(Native Method)
在javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$10(Unknown Source)
在javafx.graphics/com.sun.glass.ui.InvokeLaterDispatcher$Future.run(Unknown Source)
在javafx.graphics/com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
在javafx.graphics/com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(Unknown Source)
... 还有 1 行
应用程序启动时出现异常 application.Shapes
包 application;
import javafx.application.Application;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.StackPane;
import javafx.scene.shape.Rectangle;
import javafx.geometry.Insets;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.scene.shape.Line;
import javafx.stage.Stage;
import javafx.scene.Group;
import javafx.scene.Scene;
public class Shapes extends Application {
@Override
public void start(Stage primaryStage) {
BorderPane root = new BorderPane();
Scene scene = new Scene(root,400,400);
scene.getStylesheets().add(getClass().getResource("application.css").toExternalForm());
primaryStage.setScene(scene);
primaryStage.show();
//创建矩形并设置属性
Rectangle rectangle = new Rectangle();
rectangle.setX(50);
rectangle.setY(50);
rectangle.setWidth(100);
rectangle.setHeight(100);
rectangle.setStroke(Color.BLUE);
rectangle.setStrokeWidth(3);
rectangle.setFill(Color.BLUE);
//创建圆并设置属性
Circle circle = new Circle(50);
circle.setStroke(Color.RED);
circle.setStrokeWidth(3);
circle.setFill(Color.RED);
//创建十字架并设置属性
Line vertical = new Line(-50 / 1.5, -50 / 2.5, 50 / 1.5, -50 / 2.5);
Line horizontal = new Line(0, -50, 0, 50);
horizontal.setStroke(Color.GREEN);
horizontal.setStrokeWidth(6);
vertical.setStroke(Color.GREEN);
vertical.setStrokeWidth(6);
//创建包含十字架的面板
StackPane cross = new StackPane(vertical, horizontal);
//创建网格并设置其属性
GridPane grid = new GridPane();
grid.setPadding(new Insets(5, 5, 5, 5));
//将形状添加到网格
grid.add(cross, 2, 2);
grid.add(rectangle, 0, 0);
grid.add(circle, 1, 1);
grid.add(new Group(vertical, horizontal), 2, 2);
//创建场景并添加面板
Scene newScene = new Scene(grid);
//设置标题
primaryStage.setTitle("Shapes");
//将场景添加到舞台
primaryStage.setScene(newScene);
//显示舞台
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
<details>
<summary>英文:</summary>
enter image description hereNo other indications tell me the code is wrong except for when I try to run my code I get these errors.
```none
Exception in Application start method
java.lang.reflect.InvocationTargetException
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.base/java.lang.reflect.Method.invoke(Unknown Source)
at javafx.graphics/com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(Unknown Source)
at javafx.graphics/com.sun.javafx.application.LauncherImpl.launchApplication(Unknown Source)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.base/java.lang.reflect.Method.invoke(Unknown Source)
at java.base/sun.launcher.LauncherHelper$FXHelper.main(Unknown Source)
Caused by: java.lang.RuntimeException: Exception in Application start method
at javafx.graphics/com.sun.javafx.application.LauncherImpl.launchApplication1(Unknown Source)
at javafx.graphics/com.sun.javafx.application.LauncherImpl.lambda$launchApplication$2(Unknown Source)
at java.base/java.lang.Thread.run(Unknown Source)
Caused by: java.lang.IllegalArgumentException: StackPane@4df22f20is already inside a scene-graph and cannot be set as root
at javafx.graphics/javafx.scene.Scene$8.invalidated(Unknown Source)
at javafx.base/javafx.beans.property.ObjectPropertyBase.markInvalid(Unknown Source)
at javafx.base/javafx.beans.property.ObjectPropertyBase.set(Unknown Source)
at javafx.graphics/javafx.scene.Scene.setRoot(Unknown Source)
at javafx.graphics/javafx.scene.Scene.<init>(Unknown Source)
at javafx.graphics/javafx.scene.Scene.<init>(Unknown Source)
at application.Shapes.start(Shapes.java:64)
at javafx.graphics/com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$9(Unknown Source)
at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runAndWait$11(Unknown Source)
at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$9(Unknown Source)
at java.base/java.security.AccessController.doPrivileged(Native Method)
at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$10(Unknown Source)
at javafx.graphics/com.sun.glass.ui.InvokeLaterDispatcher$Future.run(Unknown Source)
at javafx.graphics/com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at javafx.graphics/com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(Unknown Source)
... 1 more
Exception running application application.Shapes
package application;
import javafx.application.Application;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.StackPane;
import javafx.scene.shape.Rectangle;
import javafx.geometry.Insets;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.scene.shape.Line;
import javafx.stage.Stage;
import javafx.scene.Group;
import javafx.scene.Scene;
public class Shapes extends Application {
@Override
public void start(Stage primaryStage) {
BorderPane root = new BorderPane();
Scene scene = new Scene(root,400,400);
scene.getStylesheets().add(getClass().getResource("application.css").toExternalForm());
primaryStage.setScene(scene);
primaryStage.show();
//create rectangle and set properties
Rectangle rectangle = new Rectangle();
rectangle.setX(50);
rectangle.setY(50);
rectangle.setWidth(100);
rectangle.setHeight(100);
rectangle.setStroke(Color.BLUE);
rectangle.setStrokeWidth(3);
rectangle.setFill(Color.BLUE);
//create circle and set properties
Circle circle = new Circle(50);
circle.setStroke(Color.RED);
circle.setStrokeWidth(3);
circle.setFill(Color.RED);
//create cross and set properties
Line vertical = new Line(-50 / 1.5, -50 / 2.5, 50 / 1.5, -50 / 2.5);
Line horizontal = new Line(0, -50, 0, 50);
horizontal.setStroke(Color.GREEN);
horizontal.setStrokeWidth(6);
vertical.setStroke(Color.GREEN);
vertical.setStrokeWidth(6);
//create pane to hold cross
StackPane cross = new StackPane(vertical, horizontal);
//create grid and set its properties
GridPane grid = new GridPane();
grid.setPadding(new Insets(5, 5, 5, 5));
//add shapes to grid
grid.add(cross, 2, 2);
grid.add(rectangle, 0, 0);
grid.add(circle, 1, 1);
grid.add(new Group(vertical, horizontal), 2, 2);
//create scene and add pane
Scene newScene = new Scene(grid);
//set name
primaryStage.setTitle("Shapes");
//add the scene to the stage
primaryStage.setScene(newScene);
//display stage
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
答案1
得分: 0
我明白了。我去掉了 //BorderPane root = new BorderPane();
Scene scene = new Scene(root, 400, 400);
scene.getStylesheets().add(getClass().getResource("application.css").toExternalForm());
primaryStage.setScene(scene);
primaryStage.show(); //
英文:
I got it. I removed //BorderPane root = new BorderPane();
Scene scene = new Scene(root,400,400);
scene.getStylesheets().add(getClass().getResource("application.css").toExternalForm());
primaryStage.setScene(scene);
primaryStage.show();//
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