Fix potential NPE for localFileListAdapter

Signed-off-by: alperozturk <alper_ozturk@proton.me>

app/src/main/java/com/owncloud/android/ui/fragment/ExtendedListFragment.java

@@ -257,6 +257,7 @@ public class ExtendedListFragment extends Fragment implements
         handler.removeCallbacksAndMessages(null);
         RecyclerView.Adapter adapter = getRecyclerView().getAdapter();
         Activity activity = getActivity();
+
         if (activity != null) {
             if (activity instanceof FileDisplayActivity) {
                 if (isBackPressed && TextUtils.isEmpty(query)) {
@@ -278,8 +279,7 @@ public class ExtendedListFragment extends Fragment implements
                                     new SearchEvent(query, SearchRemoteOperation.SearchType.FILE_SEARCH)
                                                           );
                             }
-                        } else if (adapter instanceof LocalFileListAdapter) {
-                            LocalFileListAdapter localFileListAdapter = (LocalFileListAdapter) adapter;
+                        } else if (adapter instanceof LocalFileListAdapter localFileListAdapter) {
                             localFileListAdapter.filter(query);
                         }
                     });
@@ -288,10 +288,12 @@ public class ExtendedListFragment extends Fragment implements
                         searchView.clearFocus();
                     }
                 }
-            } else if (activity instanceof UploadFilesActivity) {
+            } else if (activity instanceof UploadFilesActivity uploadFilesActivity) {
                 LocalFileListAdapter localFileListAdapter = (LocalFileListAdapter) adapter;
-                localFileListAdapter.filter(query);
-                ((UploadFilesActivity) activity).getFileListFragment().setLoading(false);
+                if (localFileListAdapter != null) {
+                    localFileListAdapter.filter(query);
+                    uploadFilesActivity.getFileListFragment().setLoading(false);
+                }
             } else if (activity instanceof FolderPickerActivity) {
                 ((FolderPickerActivity) activity).search(query);
             }