I found set presentsWithTransaction = true will solve this nextDrawable delay....... But will crashes sometimes..... Application Specific Information: *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Modifications to the layout engine must not be performed from a background thread after it has been accessed from the main thread.' I didn't modify any layout in background thread...... Very strange...

I tried the guideline you paste here, using autoreleasePool to wrap, and using commandbuffer.present , and the nextDrawable still take much time..... I don't think I get drawable is early..... I do nothing just present it... it shouldn't take much time.....

Any way to get animation accurate interpolation？ Any updates?

Is there any other system api can get this value? By not using UINavigationBar?

Any updates?

Hi , Thx for your resp. But I wonder how to get this value when UINavigationBar is not on my screen? I m doing some customized UI. And I want to get this value when UINavigationBar is not on my screen. Thx😄

Emm my core purpose is to get current animation interpolation of blueBox, is there a animation callback for me to get this value during animation?

Emm calling in a loop is not what I want.....What If the animation has a curve? I just want a animation callback and get interpolation when animation updatess....

I know the Animator is not exist in iOS .I just want the API like this in iOS,but I didn't find that.....So I want to know how to do this😄

I want invoke a method during animation,this method is in other framework not related with iOS SDK.And I need to update the value using animation interpolation.