title: How do you check to see if a variable has changed every second or less in objective c?
body: <p>I am using an if statement to check the value of a BOOLEAN when i click on a button. When the button is clicked if the value is false i want to display a UIActivityIndicator and if the value is true i want to push the new view. I can do this fine but i want the view to change automatically when the BOOLEAN Becomes true if the user has already clicked the button. </p>
  
  <p>So my question is how do you check to see if a value has changed everysecond or less?</p>