身份证号的格式化输入

123456 1234 1234 1234 格式 6-4-4-4的输入

-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    NSLog(@"%@",NSStringFromRange(range));
    
    
    if (textField) {//在这判断是身份证输入的textField
        NSString* text = textField.text;
                        //删除
        if([string isEqualToString:@""]){
            
                //删除一位
            if(range.length == 1){
                    //最后一位,遇到空格则多删除一次
                if (range.location == text.length-1 ) {
                    if ([text characterAtIndex:text.length-1] == ' ') {
                        [textField deleteBackward];
                    }
                    return YES;
                }
                    //从中间删除
                else{
                    NSInteger offset = range.location;

                    if (range.location < text.length && [text characterAtIndex:range.location] == ' ' && [textField.selectedTextRange isEmpty]) {
                        [textField deleteBackward];
                        offset --;
                    }
                    [textField deleteBackward];
                    textField.text = [self parseString:textField.text];
                    UITextPosition *newPos = [textField positionFromPosition:textField.beginningOfDocument offset:offset];
                    textField.selectedTextRange = [textField textRangeFromPosition:newPos toPosition:newPos];
                    return NO;
                }
            }
            else if (range.length > 1) {
                BOOL isLast = NO;
                    //如果是从最后一位开始
                if(range.location + range.length == textField.text.length ){
                    isLast = YES;
                }
                [textField deleteBackward];//删除emoji表情
                textField.text = [self parseString:textField.text];
                
                NSInteger offset = range.location;
                if (range.location == 6 || range.location  == 8) {
                    offset ++;
                }
                if (isLast) {
                        //光标直接在最后一位了
                }else{
                    UITextPosition *newPos = [textField positionFromPosition:textField.beginningOfDocument offset:offset];
                    textField.selectedTextRange = [textField textRangeFromPosition:newPos toPosition:newPos];
                }
                
                return NO;
            }
            
            else{
                return YES;
            }
        }
        
        else if(string.length >0){
            
                //限制输入字符个数
            if (([self noneSpaseString:textField.text].length + string.length - range.length > 21) ) {
                return NO;
            }

            [textField insertText:string];
            textField.text = [self parseString:textField.text];

            NSInteger offset = range.location + string.length;
            if (range.location == 6 || range.location  == 11 || range.location  == 16||range.location  == 21) {
                offset ++;
            }
            UITextPosition *newPos = [textField positionFromPosition:textField.beginningOfDocument offset:offset];
            textField.selectedTextRange = [textField textRangeFromPosition:newPos toPosition:newPos];
            return NO;
        }else{
            return YES;
        }
        
    }
    
    return YES;
}

-(NSString*)noneSpaseString:(NSString*)string
{
    return [string stringByReplacingOccurrencesOfString:@" " withString:@""];
}

- (NSString*)parseString:(NSString*)string
{
    if (!string) {
        return nil;
    }
    NSMutableString* mStr = [NSMutableString stringWithString:[string stringByReplacingOccurrencesOfString:@" " withString:@""]];
    if (mStr.length >6) {
        [mStr insertString:@" " atIndex:6];
    }if (mStr.length > 11) {
        [mStr insertString:@" " atIndex:11];
        
    }if (mStr.length > 16) {
        [mStr insertString:@" " atIndex:16];
        
    }if (mStr.length > 21) {
        [mStr insertString:@" " atIndex:21];
        
    }
    
   return  mStr;
}