Re: Cancel CellList selection

I tried to use the similar code for PromptingSelectionModel class. It works but the only different is that for unsaved form data, although it prevents the selection of next cell it leaves a mild yellow selection on. So I see blue selection of first cell and mild yellow selection on second cell. Do I need to clear that selection on second cell if unsaved form data and window.confirm yields true?

On Thursday, November 10, 2011 5:12:57 AM UTC-6, Thomas Broyer wrote:

It's not about cancelling the event; it's about *not* routing it to a DefaultSelectionEventManager (which changes selection depending on the event). It also means you shouldn't addCellPreviewHandler, but instead use the two-argument overload of setSelectionModel.

It's as easy as:

myCellList.setSelectionModel(mySelectionModel, CellPreviewEvent.Handler<MyObject>() {

   private final CellPreviewEvent.Handler<MyObject> defaultSelectionManager = DefaultSelectionEventManager.createDefaultManager();

   @Override

   public void onCellPreview(CellPreviewEvent<MyObject> event) {

      if (hasUnsavedChanged() && !Window.prompt("There are unsaved changes, are you sure you want to continue?") {

         return;

      }

      return defaultSelectionManager.onCellPreview(event);

   }

});

Beware though, if you have a cell that "handlesSelection()", you'll have to handle the case there (so that it doesn't change selection if there are unsaved changes).

Oh, and it just occurred to me that you could also simply code that within your SelectionModel too:

class PromptingSelectionModel<T> extends SingleSelectionModel<T> {

   @Override

   public void setSelected(T object, boolean selected) {

      if (hasUnsavedChanged() && !Window.prompt("There are unsaved changes, are you sure you want to continue?") {

         return;

      }

      super.setSelected(object, selected);

   }

}

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