Designing for iOS embodies the following three themes, “Deference, The UI helps people understand and interact with the content, but never competes with it, Clarity, Text is legible at every size, icons are precise and lucid, adornments are subtle and appropriate, and a sharpened focus on functionality motivates the design, and Depth, Visual layers and realistic motion impart vitality and heighten people’s delight and understanding.” If you’re redesigning an older app or creating a new one you need to approach the job in this way, First, look past the UI to the app’s core functionality and affirm its relevance. Next, use the themes of iOS to inform the design of the UI and the user experience. Add details and embellishments with care and never gratuitously. Finally, be sure to design your UI to adapt to various devices and modes so that users can enjoy your app in as many contexts as possible.
Here are some ways iOS defers to the user’s content, with a focus on functionality, using the whole screen, the weather app is a great example, reconsider visual indicators of physicality and realism, bezels, gradients, and drop shadows sometimes lead to heavier UI elements that can overpower or compete with the content so instead, focus on the content and let the UI play a supporting role, and translucent elements, the pull down on the iPhone which shows content, but shows what is also behind it.
Providing clarity is another way to make the important things stand out in an app, like using negative space, let color simplify the UI, legibility of fonts, and border-less buttons. You should use depth to communicate by creating a hierarchy on certain pages. “On a device that supports 3D Touch, peek, pop, and quick actions give users access to important functionality without losing their context. By using a translucent background and appearing to float above the Home screen, folders separate their content from the rest of the screen. Reminders displays lists in layers, as shown here. When users work with one list, the other lists are collected together at the bottom of the screen. Calendar uses enhanced transitions to give users a sense of hierarchy and depth as they move between viewing years, months, and days. In the scrolling year view shown here, users can instantly see today’s date and perform other calendar tasks. When users select a month, the year view zooms in and reveals the month view. Today’s date remains highlighted and the year appears in the back button, so users know exactly where they are, where they came from, and how to get back. A similar transition happens when users select a day: The month view appears to split apart, pushing the current week to the top of the screen and revealing the hourly view of the selected day. With each transition, Calendar reinforces the hierarchical relationship between years, months, and days.”
In “The Flat Design Era”“Flat design is a graphic style that aims to avoid any graphic element providing no significant value to the structure of a template.” With this, any gradients, volumes, or realistic forms are taken out and only the simplest objects are used. It is a minimalist approach to design. “Skeuomorphism is basically the way designs often borrow a particular feature from the past, even when the functional need for it is gone. Its a physical ornament or design on an object copied from a form of the object when made from another material or by other techniques.” Most designs are moving away from skeuomorphism, but Apple has adopted it for iOS and since then it has become popular again. There is not a huge difference when it comes to flat design and skeuomorphism. Flat design is skeuomorphic.