如何在If语句之前添加“如果按下按钮”作为条件

I am writing my first app, and inside the code i have an If statement with the condition that digit must be entered, but i want to proceed if the HOME1 button is pressed no matter if digit is entered. So should I add it in the condition, or write another IF statement? It is because even if there are no digits, user should be able to press home button.I am writing my first app, and inside the code