Image viewer in JavaFX

To display the images as a thumbnail, create a class that will extend from ListView and implement a custom cell factory as follows:

private void setCustomCellFactory(){
		setCellFactory(new Callback<ListView<ImageView>, ListCell<ImageView>>(){

			@Override
			public ListCell<ImageView> call(ListView<ImageView> arg0) {
				   ListCell<ImageView> cell = new ListCell<ImageView>(){

					@Override
					protected void updateItem(ImageView imageView, boolean flag) {
						super.updateItem(imageView, flag);
						if(imageView != null){
                           imageView.setFitHeight(80);
                           imageView.setFitWidth(100);
						}
						setGraphic(imageView);
					}
					  
				   };
				   
				   
				   cell.addEventHandler(javafx.scene.input.MouseEvent.MOUSE_CLICKED, 
						new EventHandler<javafx.scene.input.MouseEvent>() {

							public void handle(
									javafx.scene.input.MouseEvent event) {

								@SuppressWarnings("unchecked")
								ListCell<ImageView> view = (ListCell<ImageView>) event
										.getSource();
								int index = view.getIndex();
								ImageView selectedImageView = observableImageItems
										.get(index);
								if (selectedImageView != null
										&& selectedImageView.getImage() != null) {
									controller
											.getScene()
											.getCurrentImageView()
											.setImage(
													selectedImageView
															.getImage());
									controller.setCurrentIndex(index);
								}
							}

						});
				return cell;
			}
			
		});
	}

public class PhotoBrowserFxScene extends Scene {
	
	private PhotoBrowserFxController controller;
	
	private GridPane gridPane;
	
	private ImageView currentImageView;
	
	private TextArea commentTxtArea;
	
	private Button deleteBtn;
	
	private Button takePhotoBtn;
	
	private Arc leftArrow;
	
	private Arc rightArrow;
	
	private ThumbnailsImageViewList thumbnails;
	
	
	public PhotoBrowserFxScene(PhotoBrowserFxController controller){
		this(controller.getRootContainer(),800,700);
		this.controller = controller;
		initialize();
		addActions();
	}
	
	
	public PhotoBrowserFxScene(Parent root,double width, double height) {
		super(root,width,height);
	}
	
	private void initialize(){
		
		getGridPane().add(getCurrentImageView(), 0, 0);
		GridPane.setHalignment(getCurrentImageView(), HPos.CENTER);
		GridPane.setValignment(getCurrentImageView(), VPos.CENTER);
		GridPane.setMargin(getCurrentImageView(), new Insets(5));
		
		getGridPane().add(getCommentsTxtArea(), 1, 0);
		GridPane.setHalignment(getCommentsTxtArea(), HPos.CENTER);
		GridPane.setValignment(getCommentsTxtArea(), VPos.TOP);
		GridPane.setMargin(getCommentsTxtArea(), new Insets(20,20,30,20));
		
		getGridPane().add(getDeleteBtn(), 1, 0);
		GridPane.setHalignment(getDeleteBtn(), HPos.LEFT);
		GridPane.setValignment(getDeleteBtn(), VPos.BOTTOM);
        GridPane.setMargin(getDeleteBtn(), new Insets(0,0,0,10));
		
        getGridPane().add(getTakePhotoBtn(), 1, 0);
		GridPane.setHalignment(getTakePhotoBtn(), HPos.LEFT);
		GridPane.setValignment(getTakePhotoBtn(), VPos.BOTTOM);
		GridPane.setMargin(getTakePhotoBtn(), new Insets(0, 0, 0, 90));
		
		getGridPane().add(getLeftArrow(),0,1,2,1);
		GridPane.setHalignment(getLeftArrow(), HPos.LEFT);
		GridPane.setValignment(getLeftArrow(), VPos.CENTER);
		GridPane.setMargin(getLeftArrow(), new Insets(10,10,10,10));
		
		getGridPane().add(getRightArrow(),0,1,2,1);
		GridPane.setHalignment(getRightArrow(), HPos.RIGHT);
		GridPane.setValignment(getRightArrow(), VPos.CENTER);
		GridPane.setMargin(getRightArrow(), new Insets(10,10,10,10));

		
		getGridPane().add(getThumbnailsImages(),0,1,2,1);
		GridPane.setHalignment(getThumbnailsImages(), HPos.CENTER);
		GridPane.setValignment(getThumbnailsImages(), VPos.CENTER);
		GridPane.setMargin(getThumbnailsImages(), new Insets(30,30,30,30));
		
		controller.getRootContainer().getChildren().addAll(getGridPane());
	}