How to handle ListView item clicked action?

Question

I have my JavaFX 2.0 application, where i need to make some action, after user clicked an item in ListView element. To construct user GUI i'm using FXML, in which i have something like this:

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

And here is what i have in a Controller for this event:

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

And here is an error, i recieve, when the scene, which is for this gui is constructed:

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) 

And the last block of this exception (from here java.lang.NullPointerException) is looped.

Answer 1

FXML attributes and values are directly mapped to FX API. So to find out how to write handler you can first create required entities by API.

It seems you want to add action on ListView element on mouse click, so you need to add mouse click handler. In API it looks next way:

    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());         }     }); 

Looking at that code you can find out what in FXML you need to overrided attribute onMouseClicked:

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

And in controller you need to provide handler with MouseEvent parameter:

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