Mobile Accessibility User Interface Recommendations
Mobile Phones present different modalities of interaction that are not found in the desktop computer. This requires developers and designers to think differently about their user interfaces. Consider the commonly accepted UI Guidelines below when building your mobile application.
Formatting Content
Create a layout that fits the screen of a mobile device. Users should see primary content without zooming or scrolling horizontally.
Touch Controls
Use UI elements that are designed for touch gestures to make interaction with your app feel easy and natural.
Hit Targets
Create controls that measure at least 44 points x 44 points so they can be accurately tapped with a finger.
Text Size
Text should be at least 11 points so it's legible at a typical viewing distance without zooming. Developers should make text dynamically resizable without ruining the UI.
Contrast
Make sure there is ample contrast between the font color and the background so text is legible.
Spacing
Don't let text overlap. Improve legibility by increasing line height or letter spacing.
High Resolution
No WCAG Guideline
Provide high-resolution versions of all image assets. Images that are not @2x and @3x will appear blurry on the Retina display.
Distortion
No WCAG Guideline
Always display images at their intended aspect ratio to avoid distortion.
Organization
Create an easy-to-read layout that puts controls close to the content they modify.
Alignment
Align text, images, and buttons to show users how information is related.
The guidlines above were adapted from Apple's UI Tips