delete exeptions behoben

bin/.gitignore

@@ -1,3 +1,4 @@
+/Images/
 /Interfaces/
 /classes/
 /exceptions/

src/ui/view/GUI.java

@@ -270,18 +270,33 @@ public class GUI implements CategoryListener {
 			public void actionPerformed(ActionEvent arg0) {
 
 				Object nodeInfo = tree.getLastSelectedPathComponent();
-				DefaultMutableTreeNode selectedNode = (DefaultMutableTreeNode) nodeInfo;
-				String nodeName = selectedNode.getUserObject().toString();
-				int depthOfNode = selectedNode.getLevel();
-
-				switch (depthOfNode) {
-				case 1:
-					controller.deleteCategory(nodeName);
-					break;
-				case 2:
-					DefaultMutableTreeNode parent = (DefaultMutableTreeNode) selectedNode.getParent();
-					controller.deleteObjectInCat(nodeName, parent.getUserObject().toString());
-					break;
+				if(nodeInfo != null){
+					DefaultMutableTreeNode selectedNode = (DefaultMutableTreeNode) nodeInfo;
+					String nodeName = selectedNode.getUserObject().toString();
+					int depthOfNode = selectedNode.getLevel();
+
+					switch (depthOfNode) {
+					case 1:
+						int dialogResult = JOptionPane.showConfirmDialog (null, "Do you realy want to delete the Category " + nodeName + "?","Warning", JOptionPane.YES_NO_OPTION);
+						if(dialogResult == JOptionPane.YES_OPTION){
+							controller.deleteCategory(nodeName);
+							break;
+						}
+						else{
+						break;
+						}
+					case 2:
+						DefaultMutableTreeNode parent = (DefaultMutableTreeNode) selectedNode.getParent();
+						controller.deleteObjectInCat(nodeName, parent.getUserObject().toString());
+						break;
+				
+					default :
+						JOptionPane.showMessageDialog(new JFrame(),
+							"Please select a Category or an Object in order to delete something.");
+					}
+				}else{
+					JOptionPane.showMessageDialog(new JFrame(),
+							"Please select a Category or an Object in order to delete something.");
 				}
 
 			}