错误如下:
Undefined symbols for architecture x86_64:
"_OBJC_CLASS_$_KeyboardViewController",
referenced from: objc-class-ref in KeyboardPreferencesController.o
ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation)
原因是找不到对应的KeyboardViewController编译目标文件
解决办法:
在项目检查器的build phases中,打开compelle sources,添加对应的实现文件KeyboardViewController.mm.