从JavaFX开始：无法将javafx.scene.control.Label字段application.SceneController.myLabel设置为javafx.scene.text.Text

Question

我从JavaFX开始。

当我执行程序时，发生错误，在尝试执行此操作之前，它工作正常且按钮单击正常，但这是在我打算使按钮单击更改文本之前。

<?import javafx.scene.text.*?>
<?import javafx.scene.control.*?>
<?import java.lang.*?>
<?import javafx.scene.layout.*?>
<?import javafx.scene.layout.AnchorPane?>

<AnchorPane xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="application.SceneController">
   <children>
      <AnchorPane layoutX="-100.0" layoutY="-224.0" prefHeight="572.0" prefWidth="430.0">
         <children>
            <Button layoutX="205.0" layoutY="253.0" mnemonicParsing="false" onAction="#handleActionButton1" text="Do you want swag?" />
            <Text fx:id="myLabel" layoutX="280.0" layoutY="339.0" strokeType="OUTSIDE" strokeWidth="0.0" text="My text will change!" />
         </children>
      </AnchorPane>
   </children>
</AnchorPane>

那就是FXML，在行上，您可以看到文本为“我的文本将改变！”。在Eclipse的FXML文本编辑器上，它给了我这个错误：“您不能将’Text’分配给控制器字段’Label’。

这是我的SceneController类：

package application;

import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.scene.control.Label;

public class SceneController{

    @FXML
    private Label myLabel;

    @FXML
    public void handleActionButton1(ActionEvent event){
        System.out.println("Hello World!");
        myLabel.setText("Hello World!");
    }

}

如前所述，在获得标签之前，它将在控制台上成功输出“ Hello World”，但是现在可以了，但是不执行我的Java应用程序，这给了我一个很长的错误：

javafx.fxml.LoadException: 
/C:/Users/Neil/development/JavaFX/bin/application/appfxml.fxml:14

    at javafx.fxml.FXMLLoader.constructLoadException(Unknown Source)
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.load(Unknown Source)
    at application.Main.start(Main.java:15)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$153(Unknown Source)
    at com.sun.javafx.application.LauncherImpl$$Lambda$51/1299755900.run(Unknown Source)
    at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$166(Unknown Source)
    at com.sun.javafx.application.PlatformImpl$$Lambda$45/1051754451.run(Unknown Source)
    at com.sun.javafx.application.PlatformImpl.lambda$null$164(Unknown Source)
    at com.sun.javafx.application.PlatformImpl$$Lambda$47/1698159280.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$165(Unknown Source)
    at com.sun.javafx.application.PlatformImpl$$Lambda$46/1775282465.run(Unknown Source)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(Unknown Source)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$141(Unknown Source)
    at com.sun.glass.ui.win.WinApplication$$Lambda$37/1109371569.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.IllegalArgumentException: Can not set javafx.scene.control.Label field application.SceneController.myLabel to javafx.scene.text.Text
    at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(Unknown Source)
    at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(Unknown Source)
    at sun.reflect.UnsafeObjectFieldAccessorImpl.set(Unknown Source)
    at java.lang.reflect.Field.set(Unknown Source)
    at javafx.fxml.FXMLLoader.injectFields(Unknown Source)

Answer 1

在您的内部FXML，您定义了一个Text，如在Controller中一样，您尝试将其用作Label。

stackTrace（错误）在其声音上方大喊：

无法将 javafx.scene.control.Label 字段application.SceneController.myLabel 设置为
javafx.scene.text.Text

在您的控制器中，您需要将myLabel定义更改为

@FXML
private Text myLabel;