Intercept sorting the items of a JavaFX 8 TableView

Question

I have an applications that hosts a TableView. Whenever the user sorts the rows by clicking the header of a particular column, I need to

1. Save the current order of items,
2. Do the actual sorting,
3. Save the new order of items.

I was able to spot this:

this.tableView.sortPolicyProperty().set(t -> {
        System.out.println("saving source order");
        ... // Saving
        FXCollections.sort(tableView.getItems(), t.getComparator());
        System.out.println("saving target order");
        ... // Saving
        return true;
});

However, this throws ClassCastException pretty often. Is there a better way of saving the item permutations before and after sorting?

Answer 1

You could listen to it using the ListChangeListener the better way :)

tv.getItems().addListener(new ListChangeListener<T>(){
            @Override
            public void onChanged(javafx.collections.ListChangeListener.Change<
                                   ? extends T> c) {        
            while(c.next()){
              if(c.wasPermutated()){
                   System.out.println("is permuated");
              }
           }
       }

});

Hope it helps.