几种可能性：

1. 您没有将 UIImage + TTShare.m 链接到您的目标中。


2. 如果这是静态库的一部分，则需要添加 -all_load 到其他链接器标记构建设置，用于与图书馆关联的应用。

1. You did not link UIImage+TTShare.m into your target. So while you have the header, you're not compiling the implementation.
2. If this is part of a static library, you need to add -all_load to the Other Linker Flags build setting for the app linking against the library.