JavaFX自定义ListView单元

如何解决JavaFX自定义ListView单元

我正在使用具有列表视图的Java程序。我想使用自定义列表视图单元格。 到目前为止，这是我的代码：

这是我的部分模型：

public class SectionModel {

    String sectionName = new String();
    
    public SectionModel(String sectionName) {
        this.sectionName = sectionName;
    }
    
    public String getSectionName() {
        return sectionName;
    }
    
}

我在这里实现了setCellFactory：

@FXML
private ListView<SectionModel> selectQuizView;
ObservableList<SectionModel> gruppen; 
gruppen = FXCollections.observableArrayList(sections);
selectQuizView.setItems(gruppen);   
selectQuizView.setCellFactory(sectionCell -> new SectionListViewCellController());

这是我的ListViewCell：

public class SectionListViewCellController extends ListCell<SectionModel> {

    
    
     public SectionListViewCellController() {
            loadFXML();
        }

        private void loadFXML() {
            try {
                FXMLLoader loader = new FXMLLoader(getClass().getResource("sectionFXML.fxml"));
                loader.setController(this);
                loader.setRoot(this);
                loader.load();
            }
            catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
    
        @Override
        protected void updateItem(SectionModel section,boolean empty) {
            super.updateItem(section,empty);

       
                sectionName.setText(section.getSectionName());
                System.out.print(section.getSectionName());
            
        }
    
    
    @FXML
    private Label sectionName;

}

运行程序时，出现错误提示，并且无法正常工作。

错误消息：

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: java.lang.RuntimeException: javafx.fxml.LoadException: Root value already specified.
/Users/name/Desktop/QuiziApp/QuiziApp/target/classes/com/QuiziApp/sectionFXML.fxml

    at com.QuiziApp.SectionListViewCellController.loadFXML(SectionListViewCellController.java:28)
    at com.QuiziApp.SectionListViewCellController.<init>(SectionListViewCellController.java:17)
    at com.QuiziApp.HomeController.lambda$0(HomeController.java:106)
    at javafx.controls/javafx.scene.control.skin.ListViewSkin.createCell(ListViewSkin.java:432)
    at javafx.controls/javafx.scene.control.skin.ListViewSkin.lambda$new$9(ListViewSkin.java:207)
    at javafx.controls/javafx.scene.control.skin.VirtualFlow.getAvailableCell(VirtualFlow.java:1320)
    at javafx.controls/javafx.scene.control.skin.VirtualFlow.addLeadingCells(VirtualFlow.java:2028)
    at javafx.controls/javafx.scene.control.skin.VirtualFlow.layoutChildren(VirtualFlow.java:1250)
    at javafx.graphics/javafx.scene.Parent.layout(Parent.java:1207)
    at javafx.graphics/javafx.scene.Parent.layout(Parent.java:1214)
    at javafx.graphics/javafx.scene.Parent.layout(Parent.java:1214)
    at javafx.graphics/javafx.scene.Parent.layout(Parent.java:1214)
    at javafx.graphics/javafx.scene.Scene.doLayoutPass(Scene.java:576)
    at javafx.graphics/javafx.scene.Scene.preferredSize(Scene.java:1784)
    at javafx.graphics/javafx.scene.Scene$2.preferredSize(Scene.java:393)
    at javafx.graphics/com.sun.javafx.scene.SceneHelper.preferredSize(SceneHelper.java:66)
    at javafx.graphics/javafx.stage.Window$12.invalidated(Window.java:1086)
    at javafx.base/javafx.beans.property.BooleanPropertyBase.markInvalid(BooleanPropertyBase.java:110)
    at javafx.base/javafx.beans.property.BooleanPropertyBase.set(BooleanPropertyBase.java:145)
    at javafx.graphics/javafx.stage.Window.setShowing(Window.java:1174)
    at javafx.graphics/javafx.stage.Window.show(Window.java:1189)
    at javafx.graphics/javafx.stage.Stage.show(Stage.java:273)
    at com.QuiziApp.QuiziMain.start(QuiziMain.java:27)
    at javafx.graphics/com.sun.javafx.application.LauncherImpl.lambda$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)
Caused by: javafx.fxml.LoadException: Root value already specified.
/Users/name/Desktop/QuiziApp/QuiziApp/target/classes/com/QuiziApp/sectionFXML.fxml

    at javafx.fxml/javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2621)
    at javafx.fxml/javafx.fxml.FXMLLoader.createElement(FXMLLoader.java:2770)
    at javafx.fxml/javafx.fxml.FXMLLoader.processStartElement(FXMLLoader.java:2719)
    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.load(FXMLLoader.java:2435)
    at com.QuiziApp.SectionListViewCellController.loadFXML(SectionListViewCellController.java:25)
    ... 28 more
Exception running application com.QuiziApp.QuiziMain