问题
My app utilizes UIVisualEffectView to blur the background just like Control Center. But I discovered the iPad 2 (and Retina iPad) which can run iOS 8 isn't powerful enough to display that effect so it reverts to a gray color. I would like to be able to detect if the device the app is running on is powerful enough to display the blur effect, and if not I won't apply it, instead I'll change the background color to something that looks much better than that gray color. But I don't want to just check if the device is an iPad 2 or iPad 3rd gen (does it affect 4th as well?). Is there a better way to detect if the UIBlurEffect will appear as expected?
回答1:
Check this WWDC session: http://asciiwwdc.com/2014/sessions/419
So, and to reiterate on what devices we don't blur and that we only do the tinting on the iPad 2 and iPad 3rd generation, we just apply the tint and we skip the blur steps.
[...]
On iPad 4th generation, iPad Air, iPad Mini, iPad Mini with retina display, iPhones and the iPod touch we do both the blur and the tinting.
I guess you have to resort to checking for the machine name:
#import <sys/utsname.h>
...
struct utsname systemInfo;
uname(&systemInfo);
NSString *deviceName = [NSString stringWithCString:systemInfo.machine encoding:NSUTF8StringEncoding];
...
回答2:
Apple internally uses [UIDevice _graphicsQuality] for these kind of checks. In the following post I propose a method that does the same using only public API: https://stackoverflow.com/a/27879304/1914276
来源：https://stackoverflow.com/questions/26411227/detect-if-device-properly-displays-uivisualeffectview