When you're having an attack, you really don't want to eat anything and make your gall bladder keep contracting to send bile to your stomach. Once the pain subsides, you do want to eat more bland things because greasy and spicy foods can set it off (I know this from experience - no more gall bladder for me!).
Some of the foods that you should eat when you are experiencing a gall bladder attack include fish, poultry, meat, egg and dairy products. Fruits like cherries, tomatoes and blueberries are also good to eat when you are suffering from a gall bladder attack.