如何让textField输入框 限制输入字数的同时，还只让输入数字

如何让textField输入框 限制输入字数的同时，还只让输入数字和字母 1.  实现    UITextFieldDelegate  协议。 2.  在头文件中，定义如下变量： //最多的账户字符个数 #define ACCOUNT_MAX_CHARS 16 复制代码 3. 在实现文件中： 将 textFiled对象的delegate设置为self: m_accountField = [[UITextField alloc] initWithFrame:CGRectMake(89,26, 243, 33)]; m_accountField.borderStyle = UITextBorderStyleNone; m_accountField.font = fieldFont; m_accountField.delegate = self; 复制代码 //UITextFieldDelegate - (BOOL)textFieldShouldReturn:(UITextField *)textField; { //用户结束输入 [textField resignFirstResponder]; return YES; } - (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string // return NO to not change text { //判断是否超过 ACCOUNT_MAX_CHARS 个字符,注意要判断当string.leng>0 //的情况才行，如果是删除的时候，string.length==0 int length = textField.text.length; if (length >= ACCOUNT_MAX_CHARS && string.length >0) { return NO; } NSCharacterSet *cs; cs = [[NSCharacterSet characterSetWithCharactersInString:kAlphaNum] invertedSet]; NSString *filtered = [[string componentsSeparatedByCharactersInSet:cs] componentsJoinedByString:@""]; BOOL basic = [string isEqualToString:filtered]; return basic; } 复制代码 原文链接：http://blog.csdn.net/tangaowen/article/details/8087798