As you probably know, iOS refers to the iPhone operating system, which runs all of Apple’s mobile devices. It is a program that runs on Apple’s iOS platform and is designed for the iPhone, iPad, or iPod.

Customers worldwide want apps to run flawlessly; therefore, app speed significantly impacts the user experience. An app may appear inefficient or unresponsive to the user if it takes a while to launch or responds slowly to input. Numerous massive network requests from an app might increase data costs for the user, drain the battery of their smartphone, and irritate them to the point where they delete the program.
Following are the ways how to optimize app performance on your iPhone:
Cut Back on the Number of Views and Transparent Views
Limiting the number of views while preventing transparency will increase the efficiency of your application. We have a really useful technique that we can use to identify this overlap of transparencies quickly: Debug -> View Debugging -> Rendering -> Color Blended Layers.
Reduce the Amount of Work Performed in Functions
It should go without saying that functions like scrollViewDidScroll and cellForItemAt indexPath need to be extremely quick because they are constantly invoked.
Remember to use the “dumbest” views and cells and the setup methods that are constantly very light; for instance, there are no object allocations or layout restrictions.
You can also limit an app’s permissions to optimize its performance. For instance, you can limit permission of location, camera, and other features in GBWhatsAppto optimize its performance.
JPEG Picture Decoding
The decoding of images is one of the “usual suspects” when confronted with dropped frames problems. Typically, imageViews does this task invisibly on the main thread. But if the photos are large, this can result in persistent slowness in our apps. To alleviate this issue, you must relocate the decoding job to the background thread. However, the main thread will be free even though the operations won’t be as productive as the UIImageView’s standard decoding.
The app performance on your iPhone is also optimized when you clear the cache. For instance, KineMasteris a resource-intensive app; clearing its cache will give us an optimized app performance.
Off-Screen Rendering
Because we must prepare such items before presenting them, we may see certain off-screen rendering troubles when dealing with specific characteristics of our UI items, which translates to a significant utilization of the CPU and GPU.
Another helpful tool is Debug -> View Debugging -> Rendering -> Color Offscreen-Rendered Yellow.
With this tool, we can quickly identify those components because they are highlighted in yellow or red depending on how “heavy” they are.
Other Suggestions
Other general tips to bear in mind are:
- Measurements in a text (boudingRectWithSize) can be quite large. Avoid using them unless necessary.
- Always double-check your hierarchy structure, particularly if you’re utilizing an auto layout and need to support outdated devices.
- Put tasks in the background queue whenever it is feasible! However, pay attention to memory alerts.