static get()
Returns the device pixel density. Some examples:
PixelRatio.get() === 1mdpi Android devices (160 dpi)
PixelRatio.get() === 1.5hdpi Android devices (240 dpi)
PixelRatio.get() === 2iPhone 4, 4S
iPhone 5, 5c, 5s
iPhone 6
xhdpi Android devices (320 dpi)
PixelRatio.get() === 3iPhone 6 plus
xxhdpi Android devices (480 dpi)
PixelRatio.get() === 3.5Nexus 6