Get ListCell via ListView

javafx

Solution

Unfortunately right now there is no API to get List Cell by index or to get All children's(listcells) for ListView. One solution can be, define a new StringProperty specialIndicator in your MyObject class.

 class MyObject {

        ....//u r properties
        private StringProperty specialIndicator;

When ever you get index from network signal set this specialIndicator property of object and do forcerefresh of ListView

public void onReceivedNetWorkSignalIndex() {
 listView.getItems().get(indexFromService).setSpecialIndicator("selected");
 listView.getItems().get(indexFromService+1).setSpecialIndicator("selectedplusone");
//force refresh listview (it will trigger cellFactory again so that you can manipulate layout)
 listView.setItems(null);
 listView.setItems(allObjects);

}

As you already have custom Object ListView , i am assuming you already have custom cellFactory (if not you have to create one ) ,Modify your custom cell factory to handle this special Indicators

         listView.setCellFactory(new Callback<ListView<MyObject>, ListCell<MyObject>>() {
                    @Override
                    public ListCell<MyObject> call(ListView<MyObject> myObjectListView) {
                        ListCell<MyObject> cell = new ListCell<MyObject>(){
                            @Override
                            protected void updateItem(MyObject myObject, boolean b) {
                                super.updateItem(myObject, b);
                                if(myObject != null) {
                                    setText(myObject.getName());
                                    if("selected".equalsIgnoreCase(myObject.getSpecialIndicator())) {
                                        System.out.println("Setting new CSS/graphics for index retun from service." + myObject.getName());
                                    } else if("selectedplusone".equalsIgnoreCase(myObject.getSpecialIndicator())) {
                                        System.out.println("Setting new CSS/Graphics for index+1 returned from service" + myObject.getName());
                                    }
                              myObject.setSpecialIndicator(""); // reset it back to empty
                                }
                            }
                        };

                        return cell;
                    }
                });

Here is the whole sample Application ,you can look into it (in case the above explanation is not clear).

public class ListViewTest extends Application {


    @Override
    public void start(Stage stage) throws Exception {

        VBox root = new VBox();
        final ObservableList<MyObject> allObjects = FXCollections.observableArrayList(new MyObject("object0"), new MyObject("object1"),new MyObject("object2"),new MyObject("object3"),new MyObject("object4"));
       final  ListView<MyObject> listView = new ListView<>(allObjects);
        listView.setCellFactory(new Callback<ListView<MyObject>, ListCell<MyObject>>() {
            @Override
            public ListCell<MyObject> call(ListView<MyObject> myObjectListView) {
                ListCell<MyObject> cell = new ListCell<MyObject>(){
                    @Override
                    protected void updateItem(MyObject myObject, boolean b) {
                        super.updateItem(myObject, b);
                        if(myObject != null) {
                            setText(myObject.getName());
                            if("selected".equalsIgnoreCase(myObject.getSpecialIndicator())) {
                                System.out.println("Setting new CSS/graphics for index retun from service." + myObject.getName());
                                setText("I am selected Index from Service");
                            } else if("selectedplusone".equalsIgnoreCase(myObject.getSpecialIndicator())) {
                                System.out.println("Setting new CSS/Graphics for index+1 returned from service" + myObject.getName());
                                setText("I am selected Index +1  from Service");
                            }
                            myObject.setSpecialIndicator(""); // reset it back to empty
                        }
                    }
                };

                return cell;
            }
        });
        Button serviceIndex2 = new Button("ServiceIndex2");
        serviceIndex2.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent actionEvent) {
                int indexFromService =2;
                listView.getItems().get(indexFromService).setSpecialIndicator("selected");
                listView.getItems().get(indexFromService+1).setSpecialIndicator("selectedplusone");
                listView.setItems(null);
                listView.setItems(allObjects);
            }
        });
        root.getChildren().addAll(listView,serviceIndex2);
        Scene scene = new Scene(root,500,500);
        stage.setScene(scene);
        stage.show();

    }

    public static void main(String[] args) {
        launch(args);
    }

    class MyObject {

        private StringProperty name;
        private StringProperty specialIndicator;

        MyObject(String name) {
            this.name = new SimpleStringProperty(name);
            this.specialIndicator = new SimpleStringProperty();
        }

        public String getName() {
            return name.get();
        }

        public StringProperty nameProperty() {
            return name;
        }

        public void setName(String name) {
            this.name.set(name);
        }

        public String getSpecialIndicator() {
            return specialIndicator.get();
        }

        public StringProperty specialIndicatorProperty() {
            return specialIndicator;
        }

        public void setSpecialIndicator(String specialIndicator) {
            this.specialIndicator.set(specialIndicator);
        }
    }
}

Problem

Original source