前言
本文主要介紹使用UITextField限制只可輸入中,英文,數字，我們可以使用NSPredicate正則表達式可以過濾，下面看看詳細的步驟方法
首先設置UItextField的代理
實現如下方法:
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{ if ([self isInputRuleAndNumber:string] || [string isEqualToString:@""]) { return YES; } return NO;}然后添加事件,因為選擇輸入法聯想的詞.是不會經過textField:shouldChangeCharactersInRange:replacementString:方法的
[textField addTarget:self action:@selector(textFieldChanged:) forControlEvents:UIControlEventEditingChanged];
實現:
- (void)textFieldChanged:(UITextField *)textField { NSString *toBeString = textField.text; NSString *lastString; if(toBeString.length>0) lastString=[toBeString substringFromIndex:toBeString.length-1]; if (![self isInputRuleAndNumber:toBeString]&&[self hasEmoji:lastString]) { textField.text = [self disable_emoji:toBeString]; return; } NSString *lang = [[textField textInputMode] primaryLanguage]; if([lang isEqualToString:@"zh-Hans"]) { UITextRange *selectedRange = [textField markedTextRange]; UITextPosition *position = [textField positionFromPosition:selectedRange.start offset:0]; if(!position) { NSString *getStr = [self getSubString:toBeString]; if(getStr && getStr.length > 0) { textField.text = getStr; } } } else{ NSString *getStr = [self getSubString:toBeString]; if(getStr && getStr.length > 0) { textField.text= getStr; } }}再來實現限制:
pattern中,輸入需要驗證的通過的字符
小寫a-z
大寫A-Z
漢字/u4E00-/u9FA5
數字/u0030-/u0039
- (BOOL)isInputRuleAndNumber:(NSString *)str { NSString *pattern = @"[a-zA-Z/u4E00-/u9FA5//u0030-//u0039]"; NSPredicate *pred = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", pattern]; BOOL isMatch = [pred evaluateWithObject:str]; return isMatch;}實現判斷是否是Emoji
- (BOOL)hasEmoji:(NSString*)str{ NSString *pattern = @"[^//u0020-//u007E//u00A0-//u00BE//u2E80-//uA4CF//uF900-//uFAFF//uFE30-//uFE4F//uFF00-//uFFEF//u0080-//u009F//u2000-//u201f/r/n]"; NSPredicate *pred = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", pattern]; BOOL isMatch = [pred evaluateWithObject:str]; return isMatch;}字符限制
#define kMaxLength 20;-(NSString *)getSubString:(NSString*)string{ NSStringEncoding encoding = CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000); NSData* data = [string dataUsingEncoding:encoding]; NSInteger length = [data length]; if (length > kMaxLength) { NSData *data1 = [data subdataWithRange:NSMakeRange(0, kMaxLength)]; NSString *content = [[NSString alloc] initWithData:data1 encoding:encoding]; if (!content || content.length == 0) { data1 = [data subdataWithRange:NSMakeRange(0, kMaxLength - 1)]; content = [[NSString alloc] initWithData:data1 encoding:encoding]; } return content; } return nil;}總結
以上就是這篇文章的全部內容了，希望能對大家的學習或者工作帶來一定的幫助，如果有疑問大家可以留言交流。
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