1.ios中怎样限制textfield只能输入字母和数字

//设置键盘类型

self.textField.keyboardType = UIKeyboardTypeASCIICapable;

define kAlphaNum @"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"

//判断是否是数字，不是的话就输入失败

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string

{

NSCharacterSet *cs;

cs = [[NSCharacterSet characterSetWithCharactersInString:kAlphaNum] invertedSet];

NSString *filtered = [[string componentsSeparatedByCharactersInSet:cs] componentsJoinedByString:@""]; //按cs分离出数组,数组按@""分离出字符串

BOOLcanChange = [string isEqualToString:filtered];

return self.textField.text.length>=5?NO: canChange;

}

2.UITextField 限制只能输入中文

需求:限制UITextField只能输入中文，并且最大长度为4；

1，先声明一个UITextfield 变量；

@property (nonatomic, strong) UITextField *textField;

2，添加通知；

(void)viewDidLoad {

[super viewDidLoad];

// Do any additional setup after loading the view

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textFiledEditChanged:)name:UITextFieldTextDidChangeNotification object:self.textField];

}

3，在监听中，实现过滤非中文字符，并限制字符数量；

(BOOL)textFieldShouldReturn:(UITextField *)textField{

[textField resignFirstResponder];

//过滤非汉字字符

textField.text = [self filterCharactor:textField.text withRegex:@"[^\u4e00-\u9fa5]"];

if (textField.text.length >= 4) {

textField.text= [textField.textsubstringToIndex:4];

}

return NO;

}

(void)textFiledEditChanged:(id)notification{

UITextRangeselectedRange = self.textField.markedTextRange;

UITextPositionposition = [self.textField positionFromPosition:selectedRange.start offset:0];

if (!position) { //// 没有高亮选择的字

//过滤非汉字字符self.textField.text = [selffilterCharactor:self.textField.text withRegex:@"[^\u4e00-\u9fa5]"];if(self.textField.text.length >=4) {self.textField.text = [self.textField.text substringToIndex:4];  }

}else { //有高亮文字

//donothing

}

}

//根据正则，过滤特殊字符

(NSString)filterCharactor:(NSString)string withRegex:(NSString)regexStr{

NSStringsearchText = string;

NSErrorerror = NULL;

NSRegularExpressionregex = [NSRegularExpression regularExpressionWithPattern:regexStr options:NSRegularExpressionCaseInsensitive error:&error];

NSString *result = [regex stringByReplacingMatchesInString:searchText options:NSMatchingReportCompletion range:NSMakeRange(0, searchText.length) withTemplate:@""];

return result;

}

3.UITextField详解网站

http://www.cnblogs.com/xirui/p/5330289.html