Can not running in background

[xiaobaiso]

running your demo,then pass home button, the animation stoped.

[rogomantik]

happen to me too, gives the error when going background<->foreground
[CATransaction synchronize] called within transaction
gives 2 types of behaviors to me

1 if press home button then came back to the app with the progress still running
the animation is displayed with no rotation animation, however the percentage is correctly displayed and updated. the three lines starts from 3o'clock running clockwise
-works but not as expected (will be hidden if the progress finish and the app is foreground)

2 if press home button then came back to the app meanwhile the progress finished
-black screen, the application must be terminated manually (double press home - swipe)

[dkalinai]

Still a relevant issue