The first type:Add the. m question that is not added in the project. Reference: http://blog.csdn.net/u013243469/article/details/41118157 Detailed steps
The second type:In the error type, at least there are related classes, that is, there is no _objc_class_$_xxx, there may be member, that is, there is no member of this class.
At this point, we found the. m file for this class: There's this one on the right (mine is a double-ended)
Check the check out no, not checked: Compile, tick, compile and compile after the run tick: uncheck, compile, then tick, compile and run
The third type:Look at the top two lines:duplicate Symbol _objc_ivar_$_ysselbutton._delbtn in:/users/tangyujie/library/developer/xcode/deriveddata/dongdaemun-dwxvuryzjgpovgefhcsithkqsoul/build/ intermediates/dongdaemun.build/debug-iphonesimulator/dongdaemun.build/objects-normal/x86_64/ysaddvctopview.o
This makes sure that the problem is in the two classes of Ysselbutton and Ysaddvctopview, and my problem isYsselbutton, I'm here .Extension classes in Ysaddvctopview, but I have added an extension class with the same class name in the other class, resulting in an error
Almost basic can be solved, if not resolved, and so on, I also encountered the same problem again later.
IOS: Compile error linker command failed with exit code 1 (three cases)
