UITextField 只能输入字母、数字的方法小结

在IOS实际开发中有些UITextField需要限制输入内容，如账号、密码等，下面简单介绍其简单的实现方法，如下：

代码实现

//定义宏（限制输入内容） #define kAlphaNum  @"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789" #define kAlpha      @"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz " #define kNumbers     @"0123456789" #define kNumbersPeriod  @"0123456789." //定义UITextFiled的代理方法： - (BOOL)textField:(UITextField *)textField     shouldChangeCharactersInRange:(NSRange)range     replacementString:(NSString *)string {     NSCharacterSet *cs;     cs = [[NSCharacterSet characterSetWithCharactersInString:kAlphaNum] invertedSet];     NSString *filtered =     [[string componentsSeparatedByCharactersInSet:cs] componentsJoinedByString:@""];     BOOL basic = [string isEqualToString:filtered];     return basic; }