According to latest indications, your future iPhone could have invisible buttons that appears only when needed.
This is thanks to a patent recently granted by the US Patent and Trademark Office to Apple that lets Apple design products having invisible controls (buttons or sliders) that would only appear when needed. Dubbed “Disappearing button or slider“, the patent describes how various controls on the iPhone and other devices would normally stay hidden and fully appear only when needed.
If Apple decided to add an invisible button to your next iPhone, it would mean the button would be made of the same material as the housing of the phone for it to blend in seamlessly. The patent describes buttons potentially being backlit and motion or touch responsive. The patent also makes reference to similar technology found in your laptop’s trackpads, so that “various controls on the iPhone and other devices would normally stay hidden and fully appear only when needed.”
A slider control would operate under the same principles, remaining invisible most of the time and popping up only when activated.