fix multiselect #5970

Signed-off-by: tobiasKaminsky <tobias@kaminsky.me>

src/main/java/com/owncloud/android/ui/adapter/OCFileListAdapter.java

@@ -201,7 +201,13 @@ public class OCFileListAdapter extends RecyclerView.Adapter<RecyclerView.ViewHol
     }
 
     public int getItemPosition(OCFile file) {
-        return mFiles.indexOf(file);
+        int position = mFiles.indexOf(file);
+
+        if (shouldShowHeader()) {
+            position = position + 1;
+        }
+
+        return position;
     }
 
     public void setFavoriteAttributeForItemID(String fileId, boolean favorite) {
@@ -727,6 +733,10 @@ public class OCFileListAdapter extends RecyclerView.Adapter<RecyclerView.ViewHol
         return !TextUtils.isEmpty(currentDirectory.getRichWorkspace());
     }
 
+    public boolean isHeader(OCFile file) {
+        return VIEWTYPE_HEADER == getItemViewType(getItemPosition(file));
+    }
+
     @Override
     public int getItemViewType(int position) {
         if (shouldShowHeader()) {

src/main/java/com/owncloud/android/ui/fragment/OCFileListFragment.java

@@ -528,7 +528,9 @@ public class OCFileListFragment extends ExtendedListFragment implements
 
     @Override
     public void onHeaderClicked() {
-        ((FileDisplayActivity) mContainerActivity).startRichWorkspacePreview(getCurrentFile());
+        if (!getAdapter().isMultiSelect()) {
+            ((FileDisplayActivity) mContainerActivity).startRichWorkspacePreview(getCurrentFile());
+        }
     }
 
     @Override