Completely resolve _objc_class_$_ a filename ", referenced from: issue

PS: This article is reproduced and come, if there is a conflict, please contact me, will be deleted immediately.

This problem always occurs when you use a static library recently. Here's a summary of my solution:

1.. m file not imported
Add an error file to the compile Sources in build phases

2.. framework file not imported
Static library compilation often requires some library support to see if you have a library file that is not imported
It is also added in the link Binary with libraries in build phases

3. Repeated compilation, you may have copied the previous two places, added here two times, deleted when the system does not delete the default compiled reference address
Search Paths in Build settings delete addresses that are not used in library search Paths

4. The last problem, out of the static library generation above. There are two static libraries generated by the system compilation, one called by a real machine, and one called by a simulator.
When you import the emulator static library in the real machine test, the operation will be error, and also the call to the real machine static library during the simulator test will be error.

It is also easy to solve this problem by merging two static libraries and generating a compatible static library.

Find two static library files through show in Finder, copy two files to a folder, of course rename them, or overwrite them.
Below open the terminal, CD to the folder that holds two files.
By lipo[space]-create[space] [Real machine static library file name] [space] [emulator static library filename] [space]-output[space] [merged file name]

Then you can import this generated file into your project.

Completely resolve _objc_class_$_ a filename ", referenced from: Problem (GO)