Question

我有我的JavaFX 2.0应用程序，我需要在用户单击ListView元素中的项目后执行某些操作。要构建用户GUI我正在使用FXML，其中我有这样的东西：

        <children>
            <ListView fx:id="listView" GridPane.columnIndex="0" 
            GridPane.rowIndex="1" labelFor="$pane" 
            onPropertyChange="#handleListViewAction"/>
        </children>

以下是我在控制器中为此事件所做的事情：

        @FXML protected void handleListViewAction(ActionEvent event) {
           System.out.println("OK");
        }

这是一个错误，我接受，当这个gui的场景被构建时：

javafx.fxml.LoadException: java.lang.String does not define a property model for "property".
at javafx.fxml.FXMLLoader$Element.processEventHandlerAttributes(Unknown Source)
at javafx.fxml.FXMLLoader$ValueElement.processEndElement(Unknown Source)
at javafx.fxml.FXMLLoader.processEndElement(Unknown Source)
at javafx.fxml.FXMLLoader.load(Unknown Source)
at javafx.fxml.FXMLLoader.load(Unknown Source)
at javafx.fxml.FXMLLoader.load(Unknown Source)
at fxmlexample.FXMLExampleController.handleSubmitButtonAction(FXMLExampleController.java:49)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(Unknown Source)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventUtil.fireEventImpl(Unknown Source)
at com.sun.javafx.event.EventUtil.fireEvent(Unknown Source)
at javafx.event.Event.fireEvent(Unknown Source)
at javafx.scene.Node.fireEvent(Unknown Source)
at javafx.scene.control.Button.fire(Unknown Source)
at com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(Unknown Source)
at com.sun.javafx.scene.control.skin.SkinBase$5.handle(Unknown Source)
at com.sun.javafx.scene.control.skin.SkinBase$5.handle(Unknown Source)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventUtil.fireEventImpl(Unknown Source)
at com.sun.javafx.event.EventUtil.fireEvent(Unknown Source)
at javafx.event.Event.fireEvent(Unknown Source)
at javafx.scene.Scene$MouseHandler.process(Unknown Source)
at javafx.scene.Scene$MouseHandler.process(Unknown Source)
at javafx.scene.Scene$MouseHandler.access$1300(Unknown Source)
at javafx.scene.Scene.impl_processMouseEvent(Unknown Source)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Unknown Source)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(Unknown Source)
at com.sun.glass.ui.View.handleMouseEvent(Unknown Source)
at com.sun.glass.ui.View.notifyMouse(Unknown Source)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.access$100(Unknown Source)
at com.sun.glass.ui.win.WinApplication$2$1.run(Unknown Source)
at java.lang.Thread.run(Thread.java:722) java.lang.NullPointerException
at javafx.scene.Scene.doCSSPass(Unknown Source)
at javafx.scene.Scene.access$2900(Unknown Source)
at javafx.scene.Scene$ScenePulseListener.pulse(Unknown Source)
at com.sun.javafx.tk.Toolkit.firePulse(Unknown Source)
at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(Unknown Source)
at com.sun.javafx.tk.quantum.QuantumToolkit$8.run(Unknown Source)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.access$100(Unknown Source)
at com.sun.glass.ui.win.WinApplication$2$1.run(Unknown Source)
at java.lang.Thread.run(Thread.java:722)

此异常的最后一个块（来自此处java.lang.NullPointerException）是循环的。

Answer 1

FXML属性和值直接映射到FX API。因此，要了解如何编写处理程序，您可以先通过API创建所需的实体。

似乎您想在鼠标单击时在ListView元素上添加操作，因此您需要添加鼠标单击处理程序。在API中它看起来是下一个方式：

    final ListView lv = new ListView(FXCollections.observableList(Arrays.asList("one", "2", "3")));
    lv.setOnMouseClicked(new EventHandler<MouseEvent>() {

        @Override
        public void handle(MouseEvent event) {
            System.out.println("clicked on " + lv.getSelectionModel().getSelectedItem());
        }
    });

查看该代码，您可以在FXML中找到覆盖属性onMouseClicked所需的内容：

<ListView fx:id="listView" onMouseClicked="#handleMouseClick"/>

在控制器中，您需要使用MouseEvent参数提供处理程序：

@FXML
private ListView listView;

@FXML public void handleMouseClick(MouseEvent arg0) {
    System.out.println("clicked on " + listView.getSelectionModel().getSelectedItem());
}

Answer 2

来自@Sergey Grinev的回答可能有问题。如果你的ListView填充不够，换句话说可能有一些空白。然后你填补空白空间将不会选择改变选择。 enter image description here

解决方案：使用自定义ListCell。

定义自定义类扩展ListCell。
在updateItem函数中，您可以将项目单击事件处理程序设置为单元格根节点。

如果你不知道你有多少件物品。你永远不会这样做。你应该把时间用在空间上。

<强> Demostrate：

：

listView.setCellFactory(new AppListCellFactory());

AppListCellFactory.java：

public class AppListCellFactory implements Callback, ListCell> {

// only one global event handler
private EventHandler<MouseEvent> oneClickHandler;


public AppListCellFactory(){
    oneClickHandler = new EventHandler<MouseEvent>() {
        @Override
        public void handle(MouseEvent event) {
            Parent p = (Parent) event.getSource();
            //  do what you want to do with data.
            AppClickHandler.onAppBeanClicked((AppBean) p.getUserData());
        }
    };
}

@Override
public ListCell<AppBean> call(ListView<AppBean> param) {
    return new DemoListCell(oneClickHandler);
}

public static final class DemoListCell extends ListCell<AppBean> {

    private EventHandler<MouseEvent> clickHandler;

    /**
     * This is ListView item root node.
     */
    private Parent itemRoot;

    private Label label_AppName;
    private ImageView imgv_AppIcon;

    DemoListCell(EventHandler<MouseEvent> clickHandler) {
        this.clickHandler = clickHandler;
    }

    @Override
    protected void updateItem(AppBean app, boolean empty) {
        super.updateItem(app, empty);
        if (app == null) {
            setText(null);
            setGraphic(null);
            return;
        }
        if (null == itemRoot) {
            try {
                itemRoot = FXMLLoader.load(getClass().getResource(("fxml/appList_item.fxml")));
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
            label_AppName = (Label) itemRoot.lookup("#item_Label_AppName");
            imgv_AppIcon = (ImageView) itemRoot.lookup("#item_ImageView_AppIcon");
            itemRoot.setOnMouseClicked(clickHandler);
        }
        //  set user data. like android's setTag(Object).
        itemRoot.setUserData(app);
        label_AppName.setText(app.name);
        imgv_AppIcon.setImage(new Image(getClass().getResource("img/icon_64.png").toExternalForm()));
        setGraphic(itemRoot);
    }
}

}

Answer 3

对谢尔盖答案的一个简单修正，无需创建一个全新的listCell（在你的情况下，你可以，但我们不必在常规文本情况下）。

您只需要创建一个临时变量，该变量首先等于第一个列表项，并且会更改为每个新单击的项。一旦你尝试再次单击该项，temp变量就知道它是相同的，并且使用if语句可以解决这个问题。

临时项目是您置于最高String tempItem = "admin";

的全局项目

对我来说，我知道我的第一个字段总是被标记为“admin”，所以我这样设置它。你必须得到第一个条目并将其设置在你将用于列表选择的方法之外。

private void selUser() throws IOException
    {
    String item = userList.getSelectionModel().getSelectedItem().toString();

        if(item != tempItem)
        {
           //click, do something
        }

        tempItem = item;    
}

至于我，我使用了一个名为my method

的FXML文档

@FXML 
public void userSel(MouseEvent mouse) throws IOException
{
selUser();

}

在这种情况下，您可以只获取selUser（）方法的全部内容并将其放入userSel鼠标单击中。

Answer 4

您还可以在空白处消耗不需要的事件。

在单元工厂的call()中添加：

cell.setOnMousePressed((MouseEvent event) -> {
    if (cell.isEmpty()) {
       event.consume();
    }
});

这会停用click＆amp; dragStart也是。

我项目中的整个cellFactory示例：

public static Callback<ListView<BlockFactory>, ListCell<BlockFactory>> getCellFactory() {
    return new Callback<ListView<BlockFactory>, ListCell<BlockFactory>>() {

        @Override
        public ListCell<BlockFactory> call(ListView<BlockFactory> param) {
            ListCell<BlockFactory> cell = new ListCell<BlockFactory>() {

                @Override
                protected void updateItem(BlockFactory item, boolean empty) {
                    super.updateItem(item, empty);
                    if (item != null) {
                        ImageView img = new ImageView(item.img);
                        Label label = new Label(item.desc);
                        HBox bar = new HBox(img, label);
                        bar.setSpacing(15);
                        bar.setAlignment(Pos.CENTER_LEFT);
                        setGraphic(bar);
                    }
                }
            };
            cell.setOnMousePressed((MouseEvent event) -> {
                if (cell.isEmpty()) {
                    event.consume();
                }
            });
            return cell;
        }
    };
}

如何处理ListView项目单击操作？

4 个答案: