java.lang.ClassCastException 使用数据填充 TableView 时 class

Question

我在我的 view.fxml 中创建了一个表视图，它引用了我的控制器 class 中的 table（TableView 变量）。 showFilesTableView() 是在 initialize() 方法中调用的。

public void showFilesTableView() {

     TableColumn Name = new TableColumn<AllInfo,String>("Name");
    Name.setCellFactory(new PropertyValueFactory<AllInfo, String>("name"));
    table.getColumns().add(Name);

    TableColumn Size = new TableColumn<AllInfo,String>("Size");
    Size.setCellFactory(new PropertyValueFactory<AllInfo, String>("size"));
    table.getColumns().add(Size);

    TableColumn dmd = new TableColumn<AllInfo,String>("Date Modified");
    dmd.setCellFactory(new PropertyValueFactory<AllInfo, String>("date"));
    table.getColumns().add(dmd);

    ObservableList<AllInfo>  data= FXCollections.observableArrayList();
    File[] files = (new File(textfield.getText())).listFiles();

    for(File f: files) {

        AllInfo obj = new AllInfo();
        obj.name.set(f.getName());
        obj.size.set(String.valueOf(f.length()));
        obj.date.set(String.valueOf(f.lastModified()));

        data.add(obj);

    }
    table.setItems(data);
}

AllInfo class 是：

public class AllInfo {

    public SimpleStringProperty name = new SimpleStringProperty();
    public SimpleStringProperty size = new SimpleStringProperty();
    public SimpleStringProperty date = new SimpleStringProperty();
}

但是这个错误一直在显示....

java.lang.ClassCastException: javafx.scene.control.TableColumn cannot be cast to javafx.scene.control.TableColumn$CellDataFeatures

完整错误：

    Exception in Application start method
Exception in thread "main" java.lang.RuntimeException: Exception in Application start method
    at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:917)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication5(LauncherImpl.java:182)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.ClassCastException: javafx.scene.control.TableColumn cannot be cast to javafx.scene.control.TableColumn$CellDataFeatures
    at javafx.scene.control.cell.PropertyValueFactory.call(PropertyValueFactory.java:98)
    at com.sun.javafx.scene.control.skin.TableRowSkin.getCell(TableRowSkin.java:87)
    at com.sun.javafx.scene.control.skin.TableRowSkin.getCell(TableRowSkin.java:53)
    at com.sun.javafx.scene.control.skin.TableRowSkinBase.createCell(TableRowSkinBase.java:698)
    at com.sun.javafx.scene.control.skin.TableRowSkinBase.recreateCells(TableRowSkinBase.java:692)
    at com.sun.javafx.scene.control.skin.TableRowSkinBase.init(TableRowSkinBase.java:146)
    at com.sun.javafx.scene.control.skin.TableRowSkin.<init>(TableRowSkin.java:64)
    at javafx.scene.control.TableRow.createDefaultSkin(TableRow.java:212)
    at javafx.scene.control.Control.impl_processCSS(Control.java:872)
    at javafx.scene.Node.processCSS(Node.java:9056)
    at javafx.scene.Node.applyCss(Node.java:9153)
    at com.sun.javafx.scene.control.skin.VirtualFlow.setCellIndex(VirtualFlow.java:1964)
    at com.sun.javafx.scene.control.skin.VirtualFlow.getCell(VirtualFlow.java:1797)
    at com.sun.javafx.scene.control.skin.VirtualFlow.getCellLength(VirtualFlow.java:1879)
    at com.sun.javafx.scene.control.skin.VirtualFlow.computeViewportOffset(VirtualFlow.java:2528)
    at com.sun.javafx.scene.control.skin.VirtualFlow.layoutChildren(VirtualFlow.java:1189)
    at javafx.scene.Parent.layout(Parent.java:1087)
    at javafx.scene.Parent.layout(Parent.java:1093)
    at javafx.scene.Parent.layout(Parent.java:1093)
    at javafx.scene.Scene.doLayoutPass(Scene.java:552)
    at javafx.scene.Scene.preferredSize(Scene.java:1646)
    at javafx.scene.Scene.impl_preferredSize(Scene.java:1720)
    at javafx.stage.Window.invalidated(Window.java:846)
    at javafx.beans.property.BooleanPropertyBase.markInvalid(BooleanPropertyBase.java:109)
    at javafx.beans.property.BooleanPropertyBase.set(BooleanPropertyBase.java:144)
    at javafx.stage.Window.setShowing(Window.java:922)
    at javafx.stage.Window.show(Window.java:937)
    at javafx.stage.Stage.show(Stage.java:259)
    at sample.Main.start(Main.java:18)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication12(LauncherImpl.java:863)
    at com.sun.javafx.application.PlatformImpl.lambda$runAndWait5(PlatformImpl.java:326)
    at com.sun.javafx.application.PlatformImpl.lambda$null3(PlatformImpl.java:295)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater4(PlatformImpl.java:294)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null8(WinApplication.java:191)
    ... 1 more

我试过this，但仍然出现错误。

如何解决这个问题？

Answer 1

您将 PropertyValueFactory 用作 cellFactory 而不是 cellValueFactory。

由于您使用的是原始类型，编译器无法检查 Callback 的类型参数是否正确，这会导致编译时错误。

只需将代码中的 setCellFactory 替换为 setCellValueFactory 即可解决此问题：

Size.setCellValueFactory(new PropertyValueFactory<AllInfo, String>("size"));
...

最好将类型参数添加到 TableColumn 声明中：

TableColumn<AllInfo, String> Size = ...
...

项目 class 中包含的更多字段不足以显示数据。在本例中，PropertyValueFactory 查找返回属性、nameProperty()、sizeProperty 和 dateProperty 的方法。

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