Скачать или смотреть How to Fix UIView Animation Issues with Scaling and Constraints in iOS

Discover effective solutions for UIView animation problems related to scaling and constraints in iOS development. Learn the best practices to achieve smooth animations.
---
This video is based on the question https://stackoverflow.com/q/67504053/ asked by the user 'jalxp' ( https://stackoverflow.com/u/6512773/ ) and on the answer https://stackoverflow.com/a/67505169/ provided by the user 'Sweeper' ( https://stackoverflow.com/u/5133585/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: UIView animating to wrong position after being scaled while using constraints

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Fixing UIView Animation Issues with Scaling and Constraints in iOS

Are you struggling with animating a UILabel to match another label's size and position in your iOS application? If so, you’re not alone! Many developers encounter issues related to UIView animations, particularly when scaling and handling constraints. In this guide, we will explore a common problem and provide a straightforward solution to enhance your animations effectively.

Understanding the Problem

When attempting to animate a UILabel using constraints, you might find yourself facing unexpected behavior. For example, the animation might position the label incorrectly, primarily when applying transforms for scaling. This often happens due to transformations considering the center anchor point of the label.

To illustrate, here's a typical setup where you have two labels (firstLabel and secondLabel) that you want to animate between two states using Auto Layout constraints and transforms. Initially, you may have different constraints set for both states and perform animations like this:

[[See Video to Reveal this Text or Code Snippet]]

While the position transition can be smooth, the challenge arises when you scale the UILabel using a transform based on its size.

Solution Overview

To resolve the animation positioning problems effectively, we recommend simplifying your approach by disregarding the constraints temporarily during animations. Instead, use frame-based animations for a smoother transition. Here's how to do this step by step.

Step 1: Animate Without Constraints

When transitioning the first label to match the second label, deactivate the constraints and set the translatesAutoresizingMaskIntoConstraints property to true. This allows you to manipulate the label’s frame directly:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Transition Back to State A

To animate back from State B to State A, you will need to reactivate the constraints and set the translatesAutoresizingMaskIntoConstraints to false again:

[[See Video to Reveal this Text or Code Snippet]]

Step 3: Dealing with Text Size (Optional)

Since your main issue involved dealing with text size, ensure you apply any scaling required prior to these frame adjustments. This might mean recalibrating your sizing logic before animating the frames.

Conclusion

By following these steps, you should see a significant improvement in your UIView animations, allowing for a smoother transition without concerning yourself with anchor points or complex transformations. Simplifying your animation process by using frames can make your life easier and your UI transitions more professional.

If you've experienced challenges with animations or have additional tips, feel free to share your thoughts in the comments below. Happy coding!