made listeners for layout toggles

assignments/a3/src/main/java/Controls.java

@@ -16,6 +16,7 @@ public class Controls extends JPanel implements Observer
   private JSlider rating;
   private JRadioButton grid;
   private JRadioButton list;
+  private ButtonGroup layouts;
   private Image starImg;
   private Image gridImg;
   private Image listImg;
@@ -73,7 +74,12 @@ public class Controls extends JPanel implements Observer
     {
       public void actionPerformed(ActionEvent e)
       {
-        
+        if (!(grid.isSelected(layouts)))
+        {
+          grid.setSelected(layouts, true);
+          list.setSelected(layouts, false);
+          model.switchLayout();
+        }
       }
     });
     
@@ -82,10 +88,21 @@ public class Controls extends JPanel implements Observer
     {
       public void actionPerformed(ActionEvent e)
       {
-        
+        if (!(list.isSelected(layouts)))
+        {
+          list.setSelected(layouts, true);
+          grid.setSelected(layouts, false);
+          model.switchLayout();
+        }
       }
     });
     
+    this.layouts = new ButtonGroup();
+    layouts.add(grid);
+    layouts.add(list);
+    grid.setSelected(layouts, true);
+    list.setSelected(layouts, false);
+    
     this.fileChooser = new JFileChooser();
     this.fileButton = new JButton(folderIcon);
     fileButton.addActionListener(new ActionListener()