xcode 4.2非常可恶，原来的代码里有调用performselector:withObject:的地方无一例外获得一个警告： Semantic Issue PerformSelector may cause a leak because its selector is unknown warning倒是不影响程序运行，但是这人要是有点代码小洁癖的话，那日子就没法过了，这warning怎么看都碍眼。所以必须得想办法把它弄没了： #pragma clang diagnostic push #pragma clang diagnostic ignored \”-Warc-performSelector-leaks\” [self performSelector:nextView]; #pragma clang diagnostic pop 世界清静啦