Unusual behaviour in UIAnimation of IOS

Question

I am moving a view upward to some offset multiple times. My code is here:

for i in 0..<10 {
    UIView.animate(withDuration: TimeInterval(duration), animations: {
        view.frame = CGRect(x: view.frame.origin.x, y: view.frame.origin.y - offset, width: view.frame.size.width, height: view.frame.size.height)
    }) { (boolValue) in
        DispatchQueue.main.async {
                print("loop completed -- \(i)")
            }
    }
}

The problem is that "animation completed" is printing after outer loop completes (after 10 times), not just after that particular animation gets completed. Means , when below code get executed after 10 times

UIView.animate(withDuration: TimeInterval(duration), animations: {
    view.frame = CGRect(x: view.frame.origin.x, y: view.frame.origin.y - offset, width: view.frame.size.width, height: view.frame.size.height)
}) { (boolValue) in
    DispatchQueue.main.async {
        print("loop completed -- \(i)")
    }
}

then all completion block executes

I think this is likely a duplicate of: https://stackoverflow.com/a/14670506/8441876 — Smartcat, May 18 '18 at 06:11
Possible duplicate of [iOS - completion block in UIView animateWithDuration gets called too early](https://stackoverflow.com/questions/14669601/ios-completion-block-in-uiview-animatewithduration-gets-called-too-early) — Vinodh, May 18 '18 at 06:12
my completion block get called after outer loop get completed — krishan kumar, May 18 '18 at 06:17
I think it's a not good idea to do animation using for loop. Can you please explain purpose of animation — Hitesh Surani, May 18 '18 at 06:20
It is bcoz loop is running on main thread and that print statement is in a async block. — Mahendra, May 18 '18 at 06:20
i have to make animation like goo.gl/images/jXy3s3 @HiteshSurani — krishan kumar, May 18 '18 at 06:24
@MahendraGP i have replaced code of completion block and still not doing what i want `DispatchQueue.main.async { print("loop completed -- \(i)") }` — krishan kumar, May 18 '18 at 06:27
Use core animation to achieve this kinda of animations in app. — Mahendra, May 18 '18 at 06:36
anybody knows any library which helps in creating goo.gl/images/jXy3s3 like animation — krishan kumar, May 18 '18 at 06:48

Unusual behaviour in UIAnimation of IOS

0 Answers0