What kind of food alternative I can give to Uromastyc lizard?

[Luiz]

I have an adult Uromastyc in a 55g.

Sometimes he refuses to eat at all, but can't resist a dandelion flower. Usually the only leaves he eats is purple and green letuce and salad mix from krouger. I think this kind of food is not enough in provide nutrients to him. I have tried cricket and mealworms but don't eat either.

What kind of alternative food I can give to him. I have Google a lot about it, but didn't find
Any good source of info.

Thanks in advance.