When doing some SDK development, we will copy the example code to our own code for testing
In this process, some methods or variables will be copied
The following figure often appears
The system prompts use of unclared identifier ‘a variable’
Generally, this variable may not be defined in the. H file. If you check the header file and find that it is also defined.
However, if this problem still occurs, you need to check and add the class name in front of the method name that reports an error
After the class name is included, no error will be reported