TreeView Image бросает NullPointerException

Question

Это код моего класса контроллера:

public class Controller implements javafx.fxml.Initializable{ 

@FXML private Button btn_home ; 
@FXML private Button btn1; 
@FXML private VBox vbox_list; 
@FXML public TreeView tree_view; 
@FXML public Label lbl; 
public ImageView img; 



@Override 
public void initialize(URL arg0, ResourceBundle arg1) { 

    this.img =new ImageView(new Image(getClass().getResource("/images/Ford.png").toExternalForm())); 
    TreeViewHelper helper = new TreeViewHelper(); 
    ArrayList<TreeItem<String>> products = helper.getmakes(img); 
    tree_view.getSelectionModel().setSelectionMode(SelectionMode.SINGLE); 
    TreeItem<String> rootItem = new TreeItem<String>("Marques"); 
    rootItem.getChildren().addAll(products); 
    tree_view.setRoot(rootItem); 
    tree_view.setShowRoot(false); 
    tree_view.getSelectionModel().selectedItemProperty().addListener(new ChangeListener<TreeItem>() { 

     @Override 
     public void changed(ObservableValue<? extends TreeItem> arg0, TreeItem arg1, TreeItem arg2) { 
      // TODO Auto-generated method stub 
      System.out.println("new: " + arg2.getValue()); 
      TreeItem<String> selectedItem = (TreeItem<String>) arg2; 
      String st = arg2.getValue().toString(); 
         if (st.equals("Alfa Romeo")) 
         st = "alfa%20romeo"; 
         else if (st.equals("Mercedes-Benz")) 
         st = "mercedes%20benz"; 
         else if (st.equals("Rolls-Royce")) 
         st = "Rolls%20Royce"; 
         else if (st.equals("Aston Martin")) 
         st = "aston%20martin"; 

      System.out.println(st); 
       TreeViewHelper helper = new TreeViewHelper(); 
       ArrayList<TreeItem<String>> products = helper.getmodels(st); 
       selectedItem.getChildren().addAll(products); 
       selectedItem.setExpanded(true); 
       tree_view.requestFocus(); 
     } 
     }); 
    //System.out.print(t.get_list_makes().size()); 

} 

@FXML public void mouse_clicked() 
{ 



} 

Это код моей функции get_makes:

public ArrayList<TreeItem<String>> getmakes(ImageView m) 
    { 

    All_makes all_makes = (All_makes) new parse_object <All_makes> (All_makes.class).ParseUri("https://api.edmunds.com/api/vehicle/v2/makes?state=new&fmt=json&api_key=9t82jrgr8c3bv6vusw8j75fu"); 
    ArrayList<TreeItem<String>> makes = new ArrayList<TreeItem<String>>(); 
    for (int i = 0 ; i< all_makes.get_list_makes().size(); i++) 
    { 

     TreeItem<String> make = new TreeItem<String>(all_makes.get_list_makes().get(i).get_mk_name(),m); 
     make.setGraphic(m); 
     makes.add(make); 

    } 
    return makes; 
    } 

Я не знаю, почему я получаю java.lang.NullPointerException. Все хорошо, путь построения, путь, и когда я создаю TreeView без картинки.

Вот консольный вывод:

at javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2601) 
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2579) 
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2441) 
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3214) 
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3175) 
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3148) 
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3124) 
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3104) 
at javafx.fxml.FXMLLoader.load(FXMLLoader.java:3097) 
at application.Main.start(Main.java:35) 
at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$162(LauncherImpl.java:863) 
at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$175(PlatformImpl.java:326) 
at com.sun.javafx.application.PlatformImpl.lambda$null$173(PlatformImpl.java:295) 
at java.security.AccessController.doPrivileged(Native Method) 
at com.sun.javafx.application.PlatformImpl.lambda$runLater$174(PlatformImpl.java:294) 
at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95) 
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method) 
at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191) 
at java.lang.Thread.run(Unknown Source) 
Caused by: java.lang.NullPointerException 
    at Controller.Controller.initialize(Controller.java:56) 
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2548) 
    ... 17 more 

Где моя ошибка? :(

Answer 1

Проблема у вас возникают, когда вы загружаете изображение, вы должны использовать:.? this.img =new ImageView(new Image(getClass().getClassLoader().getResource("/images/Ford.png").toExternalForm()));

Это должно решить вашу проблему