Added feedback label in Search scene

Også lagt til en kommentar på linje 219 i Search klassen for å merke at det kastes en exception der hvis vi prøver å adde et bilde i et album når vi ikke har valgt noe album.

src/main/App/Css/Css.java

 package Css;
 
+import javafx.animation.FadeTransition;
 import javafx.geometry.Pos;
 import javafx.scene.control.*;
 import javafx.scene.layout.HBox;
@@ -8,6 +9,7 @@ import javafx.scene.layout.StackPane;
 import javafx.scene.text.Font;
 import javafx.scene.text.Text;
 import javafx.stage.Screen;
+import javafx.util.Duration;
 
 /**
  * Css class used for styling different JavaFX elements
@@ -177,6 +179,23 @@ public class Css {
         }
     }
 
+    /**
+     * Plays a fading transition on a feedback label
+     *
+     * @param feedBackType     FeedBackType Enum, the type of feedback (success or error)
+     * @param labelDisplayText text to be displayed by the label when the transition will be shown
+     * @param fontSize         the size of the font
+     * @param label            label to play the transition on
+     */
+    public static void playFeedBackLabelTransition(FeedBackType feedBackType, String labelDisplayText, int fontSize, Label label){
+        setFeedBackLabel(feedBackType, fontSize, label);
+        label.setText(labelDisplayText);
+        FadeTransition ft = new FadeTransition(Duration.seconds(5), label);
+        ft.setFromValue(1);
+        ft.setToValue(0);
+        ft.play();
+    }
+
     /**
      * Styles font of a text in the Action popup class
      *