Called when a FormItem's value is about to change as the result of user interaction. This method fires after the user
performed an action that would change the value of this field, but before the element itself is changed. Returning
false cancels the change. Note that if what you want to do is transform the user's input, for example,
automatically change separator characters to a standard separator character, you should implement FormItem.setInputTransformer(com.smartgwt.client.widgets.form.FormItemInputTransformer)
rather than using a combination of change() and
setValue() to accomplish the same thing. Returning false from change
is intended for rejecting input
entirely, such as typing invalid characters.
Note that if you ask the form for the current value in this handler,
you will get the old value because the change has not yet been commited. The new value is available as a parameter to
this method.
- Parameters:
handler
- the change handler
- Returns:
HandlerRegistration
used to remove this handler