去除两端空格:
NSString *temp = [textField.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
去除两端空格和回车:
NSString *text = [temp stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet ]];
原文：http://www.cnblogs.com/xvewuzhijing/p/4931227.html