IOS 限制输入特定字符的方法

比如限制输入字符为ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789@-_.

 

例子：

 

+(BOOL) isStringInCharacterSet:(NSString*) str  (需要判断的字符串)

{

    static NSString* s_strEmailChar = @"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789@-_.";

    NSCharacterSet* charset = [NSCharacterSet characterSetWithCharactersInString:s_strEmailChar];

    NSCharacterSet* cs = [charSet invertedSet];

    NSString *filtered = [[str componentsSeparatedByCharactersInSet:cs] componentsJoinedByString:@""];

    return [str isEqualToString:filtered];

}