原文
Windows Phone 8.1 Update 2 will never get to most Windows Phones, but it
certainly has a number of features which I wish was supported on my handset.
In the above picture we see another unannounced feature, demonstrated on the
Lumia 640, which allows users to suspend their device by double tapping
on the navigation bar.
This feature is particularly useful for those who want to preserve the
buttons of their device for later resale, allowing users to both switch on
and off their device without using any buttons at all.
资料来源:WMPU http://goo.gl/ITKj8L