When implementing a UISlider, it is a good idea to consider how much the slider value should change when swiping up/down to adjust it. It might not always make sense to do it in 10% increments, which is the default behaviour.

Could be because the value at those intervals doesn't make sense, or feel random, or because it wouldn't provide the user with a fine enough control being able to go through the whole slider in just 10 swipes.
It user will still be able to adjust the slider to any value by double tapping and holding and then moving the finger left or right, bypassing VoiceOver gestures. VoiceOver announces the new value as it changes.
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Check for the traversal order of elements in your app. Sometimes, the default top-left to bottom-right order might not be the most logical one. Sometimes, you may consciously want to tweak the order. Some other times, grouping is the answer.

Touch target sizes are recommended to be at least 44 x 44 points. Buttons in the navigation bar ( especially when not using nav bar button items), dismiss buttons, and custom toolbars, are use cases that tend to have smaller sizes.

@azzoor is the developer of the Braille Scanner It uses computer vision to locate the page and Machine Learning to match Braille to letters. You can see English letters above the braille, convert them to speech, copy and paste it... so cool!