How to add image tooltips to ComboBox items in JavaFX?

Question

I would like to add a photo to each item in a ComboBox so when the user hovers over the name of that item in the ComboBox , the photo of that item will be displayed.

Here is my code:

    lights.setConverter(new StringConverter<Light>() {
        @Override
        public String toString(Light object) {
            return object.getName();
        }

        @Override
        public Light fromString(String string) {
            return null;
        }
    });



    lights.setItems(FXCollections.observableArrayList
           (new Light ("Incandescent", 5.23),
            new Light ("Halogen", 5.75),
            new Light ("fluorescent",7.29),
            new Light ("Compact fluorescent bulbs",4.83),
            new Light ("LED",4.83)));


    lights.setPromptText("Please select a light");
    lights.setPrefWidth(100);


         lights.valueProperty().addListener((obs, oldVal, newVal) -> {
         String selectionText = "The price for the " + newVal.getName() + " light is : $" + newVal.getPrice();
       lightNamePrice.setText(selectionText);
    });

 private class Light {
    private String name;
    private Double price;

    private Double getPrice() {
        return price;
    }

    private String getName() {
        return name;
    }

    private Light(String name, Double price) {
        this.name = name;
        this.price = price;

    }

}

Anyone got any ideas? I am fairly new at JavaFX so any help I can get will be great.

Answer 1

You could use setCellFactory method of your ComboBox to customize the rendering of the items in the drop-down list in a way to return a ListCell which has a Tooltip attached as ListCell is a subclass of Control therefore it provides setTooltip method.

Example

I have updated the Light class to make every instance of this class able to have its own image:

private class Light {
    private String name;
    private Double price;
    private Image image;

    public Image getImage() {
        return image;
    }

    private Double getPrice() {
        return price;
    }

    private String getName() {
        return name;
    }

    private Light(String name, Double price, Image image) {
        this.name = name;
        this.price = price;
        this.image = image;
    }
}

Then I have updated the code which fills up the data to use the (same) Image :

Image image =  new Image(getClass().getResource("light.png").toExternalForm(), 100, 100, true, true);

lights.setItems(FXCollections.observableArrayList
       (new Light ("Incandescent", 5.23, image),
        new Light ("Halogen", 5.75, image),
        new Light ("fluorescent",7.29, image),
        new Light ("Compact fluorescent bulbs",4.83, image),
        new Light ("LED",4.83, image)));

Then finally the update on the cell factory:

lights.setCellFactory(param -> {
    return new ListCell<Light>() {

        @Override
        public void updateItem(Light item, boolean empty) {
            super.updateItem(item, empty);

            if (item != null) {
                setText(item.getName());

                // Add the Tooltip with the image of the current item
                Tooltip tt = new Tooltip();
                tt.setGraphic(new ImageView(item.getImage()));

                setTooltip(tt);
            } else {
                setText(null);
                setTooltip(null);
            }
        }
    };
});

And the result:

You can also check this question about image-tooltips: How to show Image as tooltip in JavaFX?