refactor: dedicated loadPaneToDialog function replacing the previous workaround

src/main/java/ch/zhaw/gartenverwaltung/PlantsController.java

@@ -21,7 +21,6 @@ import javafx.scene.image.Image;
 import javafx.scene.image.ImageView;
 import javafx.scene.layout.AnchorPane;
 import javafx.scene.layout.VBox;
-import javafx.stage.Stage;
 
 import java.io.IOException;
 import java.time.LocalDate;
@@ -74,7 +73,6 @@ public class PlantsController {
      */
     @FXML
     void selectSowDate() throws IOException {
-        Stage stage = new Stage();
         Dialog<LocalDate> dateSelection = new Dialog<>();
         dateSelection.setTitle("Select Date");
         dateSelection.setHeaderText(String.format("Select Harvest/Sow Date for %s:", selectedPlant.name()));
@@ -85,12 +83,10 @@ public class PlantsController {
         ButtonType sowButton = new ButtonType("Save", ButtonBar.ButtonData.OK_DONE);
         dialogPane.getButtonTypes().addAll(sowButton, ButtonType.CANCEL);
 
-        if (appLoader.loadSceneToStage("SelectSowDay.fxml", stage) instanceof SelectSowDayController controller) {
+        if (appLoader.loadPaneToDialog("SelectSowDay.fxml", dialogPane) instanceof SelectSowDayController controller) {
             controller.initSaveButton((Button) dialogPane.lookupButton(sowButton));
             controller.setSelectedPlant(selectedPlant);
             dateSelection.setResultConverter(button -> button.equals(sowButton) ? controller.retrieveResult() : null);
-        }
-        dialogPane.setContent(stage.getScene().getRoot());
 
             dateSelection.showAndWait()
                     .ifPresent(date -> {
@@ -102,6 +98,7 @@ public class PlantsController {
                         plantsRoot.fireEvent(new ChangeViewEvent(ChangeViewEvent.CHANGE_MAIN_VIEW, "MyGarden.fxml"));
                     });
         }
+    }
 
     /**
      * fill list view with current hardiness zone

src/main/java/ch/zhaw/gartenverwaltung/bootstrap/AppLoader.java

@@ -12,6 +12,7 @@ import ch.zhaw.gartenverwaltung.models.GardenSchedule;
 import ch.zhaw.gartenverwaltung.models.PlantListModel;
 import javafx.fxml.FXMLLoader;
 import javafx.scene.Scene;
+import javafx.scene.control.DialogPane;
 import javafx.scene.layout.Pane;
 import javafx.stage.Stage;
 
@@ -78,6 +79,24 @@ public class AppLoader {
         return controller;
     }
 
+    /**
+     * Loads the given fxml-file from resources (no caching) and appendeds it's
+     * contents to the given {@link DialogPane}.
+     * Performs dependency-injection.
+     *
+     * @param fxmlFile The file name to be loaded
+     * @param appendee The {@link DialogPane} to which the FXML contents are to be appended.
+     * @return The controller of the loaded scene.
+     * @throws IOException if the file could not be loaded
+     */
+    public Object loadPaneToDialog(String fxmlFile, DialogPane appendee) throws IOException {
+        FXMLLoader loader = new FXMLLoader(Objects.requireNonNull(HelloApplication.class.getResource(fxmlFile)));
+        appendee.setContent(loader.load());
+        Object controller = loader.getController();
+        annotationInject(controller);
+        return controller;
+    }
+
     /**
      * Loads the given fxml-file from resources and caches the pane.
      * Performs dependency-injection.