为什么我收到CIFilter的“无法识别的选择器发送给类”错误？

Question

This code works on an iPad 2 simulator, but not on my physical iPad 2 (which is running on iOS 7.0.6):

var fade = CIFilter(name: "CIExposureAdjust", withInputParameters:["inputEV" : -2.0 ])

The full error message says:

[CIFilter filterWithName:withInputParameters:]: unrecognized selector sent to class 0x392d8d9c 2015-07-05 23:12:37.106 *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '+[CIFilter filterWithName:withInputParameters:]: unrecognized selector sent to class 0x392d8d9c'

Answer 1

Check the official documentation of + filterWithName:withInputParameters:

+ filterWithName:withInputParameters:

Availability
Available in iOS 8.0 and later.

Since your iPad is running on iOS 7, this method is not available, and therefore your app crashes.

A few possible solutions:

1. Use - respondsToSelector: to check if the method exists.

2. Check if the current foundation version number, NSFoundationVersionNumber is higher than NSFoundationVersionNumber_iOS_7_1 .

3. Make iOS 8 a minimum requirement for your app.