Fix problem with Fl_Tree::select_only() invoking select callbacks

before all other items have first been deselected.

Also: added some related demo code to tree-simple to demonstrate
'reselect' callbacks, where a callback can be invoked when an item
that's selected already is 're-selected'.



git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@10015 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

examples/tree-simple.cxx

@@ -43,6 +43,13 @@ void TreeCallback(Fl_Widget *w, void *data) {
       break;
     case FL_TREE_REASON_CLOSED:
       // fprintf(stderr, "TreeCallback: Item '%s' closed\n", item->label());
+      break;
+#if FLTK_ABI_VERSION >= 10301
+    // To enable this callback, use tree->item_reselect_mode(FL_TREE_SELECTABLE_ALWAYS);
+    case FL_TREE_REASON_RESELECTED:
+      // fprintf(stderr, "TreeCallback: Item '%s' reselected\n", item->label());
+      break;
+#endif
     default:
       break;
   }

src/Fl_Tree.cxx

@@ -1317,29 +1317,33 @@ int Fl_Tree::select_only(Fl_Tree_Item *selitem, int docallback) {
   selitem = selitem ? selitem : first();	// NULL? use first()
   if ( ! selitem ) return(0);
   int changed = 0;
+  // Deselect everything first.
+  //    Prevents callbacks from seeing more than one item selected.
+  //
   for ( Fl_Tree_Item *item = first(); item; item = item->next() ) {
-    if ( item == selitem ) {
+    if ( item == selitem ) continue;		// don't do anything to selitem yet..
-#if FLTK_ABI_VERSION >= 10301
-      // NEW
-      if ( item->is_selected() ) {		// already selected?
-        if ( item_reselect_mode() == FL_TREE_SELECTABLE_ALWAYS ) {
-	  select(item, docallback);		// handles callback with reason==reselect
-        }
-	continue;				// leave 'changed' unmodified (nothing changed)
-      }
-#else
-      // OLD
-      if ( item->is_selected() ) continue;	// don't count if already selected
-#endif	
-      select(item, docallback);
-      ++changed;
-    } else {
     if ( item->is_selected() ) {
       deselect(item, docallback);
       ++changed;
     }
   }
+#if FLTK_ABI_VERSION >= 10301
+  // Should we 'reselect' item if already selected?
+  if ( selitem->is_selected() && (item_reselect_mode()==FL_TREE_SELECTABLE_ALWAYS) ) {
+    // Selection unchanged, so no ++change
+    select(selitem, docallback);			// do callback with reason=reselect
+  } else if ( !selitem->is_selected() ) {
+    // Item was not already selected, select and indicate changed
+    select(selitem, docallback);
+    ++changed;
   }
+#else
+  if ( !selitem->is_selected() ) {
+    // All items deselected, now select the one we want
+    select(selitem, docallback);
+    ++changed;
+  }
+#endif
   return(changed);
 }