Question

I am making modifications to elements on UI. There is no (extra) thread or any async. calls. However I want to give a slow motion effect, so wait specific time at each step in a for loop. How can I achieve this without blocking the UI?

Specifically, I am moving a button in a for loop. I can put

 [NSThread sleepForTimeInterval:5.0];

in the loop but button’s position is not reflected on the UI until the loop ends; I think I should call something to ‘redraw’ the button at each for iteration.

Any ideas?

Answer 1

Better to use Core Animation if the modifications you are making are to animatable properties. For example, if you want to slowly change the frame of a view, you might do something like:

[UIView beginAnimations:@""];
[UIView setAnimationDuration:5.0];
view.frame = CGRectMake(0, 0, 320, 460);
[UIView commitAnimations];