JavaFX Eclipse JDK14: как устранить исключение в методе запуска приложения java .lang.reflect.InvocationTargetException? - PullRequest
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JavaFX Eclipse JDK14: как устранить исключение в методе запуска приложения java .lang.reflect.InvocationTargetException?

0 голосов
/ 16 апреля 2020

Я пытался заставить JavaFx работать на Eclipse, и я добился определенного прогресса. Но теперь я получаю эту ошибку при попытке запустить приложение: 

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(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:564)
    at javafx.graphics/com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:464)
    at javafx.graphics/com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:363)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:564)
    at java.base/sun.launcher.LauncherHelper$FXHelper.main(LauncherHelper.java:1051)
Caused by: java.lang.RuntimeException: Exception in Application start method
    at javafx.graphics/com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:900)
    at javafx.graphics/com.sun.javafx.application.LauncherImpl.lambda$launchApplication$2(LauncherImpl.java:195)
    at java.base/java.lang.Thread.run(Thread.java:832)
Caused by: javafx.fxml.LoadException: Root hasn't been set. Use method setRoot() before load.
/C:/Users/Lawrence/eclipse-workspace/Week6%20HW/bin/application/MPGCalculator.fxml:13

    at javafx.fxml/javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2621)
    at javafx.fxml/javafx.fxml.FXMLLoader$RootElement.constructValue(FXMLLoader.java:1338)
    at javafx.fxml/javafx.fxml.FXMLLoader$ValueElement.processStartElement(FXMLLoader.java:754)
    at javafx.fxml/javafx.fxml.FXMLLoader.processStartElement(FXMLLoader.java:2722)
    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2552)
    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2466)
    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3237)
    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3194)
    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3163)
    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3136)
    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3113)
    at javafx.fxml/javafx.fxml.FXMLLoader.load(FXMLLoader.java:3106)
    at application.MPGCalculator.start(MPGCalculator.java:13)
    at javafx.graphics/com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$9(LauncherImpl.java:846)
    at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runAndWait$12(PlatformImpl.java:455)
    at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$10(PlatformImpl.java:428)
    at java.base/java.security.AccessController.doPrivileged(AccessController.java:391)
    at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$11(PlatformImpl.java:427)
    at javafx.graphics/com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:96)
    at javafx.graphics/com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at javafx.graphics/com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:174)
    ... 1 more 
    Exception running application application.MPGCalculator

Я не уверен, как go решить эту ошибку.

Вот код для файла f xml: 

    <?xml version="1.0" encoding="UTF-8"?>

    <?import javafx.scene.control.Button?>
    <?import javafx.scene.control.Label?>
    <?import javafx.scene.control.TextField?>
    <?import javafx.scene.layout.AnchorPane?>
    <?import javafx.scene.layout.ColumnConstraints?>
    <?import javafx.scene.layout.GridPane?>
    <?import javafx.scene.layout.RowConstraints?>
    <?import javafx.scene.layout.VBox?>
    <?import javafx.scene.text.Font?>

    <fx:root prefHeight="359.0" prefWidth="420.0" type="VBox" xmlns="http://javafx.com/javafx/11.0.1" xmlns:fx="http://javafx.com/fxml/1" fx:controller="application.MPGCalculatorController">
      <children>
        <AnchorPane maxHeight="-1.0" maxWidth="-1.0" prefHeight="350.0" prefWidth="593.0" VBox.vgrow="ALWAYS">
          <children>
                <Label layoutX="179.0" layoutY="6.0" text="MPG Calculator" />
                <GridPane layoutX="17.0" layoutY="-1.0" prefHeight="367.0" prefWidth="381.0">
                  <columnConstraints>
                    <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
                    <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
                  </columnConstraints>
                  <rowConstraints>
                    <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
                    <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
                    <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
                  </rowConstraints>
                   <children>
                      <TextField id="gasTextField" fx:id="gasTextField" prefHeight="25.0" prefWidth="114.0" GridPane.columnIndex="1" GridPane.rowIndex="1" />
                      <Label alignment="CENTER" prefHeight="27.0" prefWidth="207.0" style="&#10;" text="Gallons used" textAlignment="CENTER" wrapText="false" GridPane.rowIndex="1">
                         <font>
                            <Font size="18.0" />
                         </font>
                      </Label>
                  <Label alignment="CENTER" prefHeight="27.0" prefWidth="207.0" style="&#10;" text="Miles travelled" textAlignment="CENTER" wrapText="false">
                    <font>
                      <Font size="18.0" />
                    </font>
                  </Label>
                      <Button mnemonicParsing="false" text="Calculate" GridPane.rowIndex="2" />
                      <TextField id="totalTextField" fx:id="totalTextField" prefHeight="25.0" prefWidth="114.0" GridPane.columnIndex="1" GridPane.rowIndex="2" />
                      <TextField id="milesTextField" fx:id="milesTextField" prefHeight="25.0" prefWidth="114.0" GridPane.columnIndex="1" />
                   </children>
                </GridPane>
          </children>
        </AnchorPane>
      </children>
    </fx:root>

Как я уже говорил, в настоящее время я использую Eclipse с JDK14 и JavaFx SDK 14. Странно, что я могу даже не запускаю более простую программу "hello world", использующую JavaFx, несмотря на правильное следование руководству. Я получаю ту же ошибку, показанную в начале этого поста.

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