Storyboard warning : First baseline layout attribu

问题:

I can't figure out how to get rid of this warning, I'm using a storyboard with many viewControllers (with labels, textfields and a lot of constraints ) all of them have been created almost the same way.

When I click on the warning it highlights a UILabel inside a scrollView :

This scrollView has many UILabels with constraints, I tried everything I could find on so including : Attribute Unavailable: First baseline layout attribute on iOS versions prior to 8.0

This Warning doesn't cause my app to crash,I've tried on the simulator and an iPhone 4 (ios 7.1.2). But I'm worried about the AppStore approval.

回答1:

I think the issue is you have many constraints that are using NSLayoutAttributeFirstBaseline and when you click on the warning Xcode is pointing to wrong constraint.

To identify the constraints search in Xcode with "firstBaseline". Change all constraints that are using NSLayoutAttributeFirstBaseline.

Note: You may need to adjust your views. In my case NSLayoutAttributeBaseline worked well.

NSLayoutAttributeFirstBaseline
The object’s baseline. For objects with more than one line of text, this is the baseline for the topmost line of text. The object’s baseline. For objects with more than one line of text, this is the baseline for the topmost line of text. Available in iOS 8.0 and later.

NSLayoutAttributeBaseline
The object’s baseline. The object’s baseline. Available in iOS 6.0 and later.