如何检查UITextFields是否为空？

I have a bunch of UITextFields where a user must enter a number (the keyboard is the number pad) before pressing a submit button. When the submit button is pressed, a "check" method is called that wants to check if the data is valid... aka not empty. Now this would be easy if it was just one textField but I have 14. I want a simple if-statement that checks if one of the fields or all of the fields are empty....I have a bunch of UITextFields where a user mus