1.判断输入框的内容是否是数字

-(BOOL)isNumText:(NSString *)str{
    NSString * regex  = @"^[0-9]*$";
    NSPredicate * pred = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",regex];
    BOOL isMatch = [pred evaluateWithObject:str];
    if (isMatch) {
        return YES;
    }else{
        return NO;
    }
}

http://www.regexlab.com/zh/regref.htm