iOS7条形码扫描仪API为UPCA条形码格式添加了零

Question

扫描这个(https://www.barcoderobot.com/static/bcgen/01026/478064310081_3b120.jpg?preview=True)条形码我们应该得到以下结果:47806431008

使用iOS7 api读取条形码,我得到以下结果:047806431008

任何ideias如何处理这个？

部分代码:

CGRect highlightViewRect = CGRectZero;
AVMetadataMachineReadableCodeObject *barCodeObject;
NSString *detectionString = nil;
NSArray *barCodeTypes = @[AVMetadataObjectTypeUPCECode, AVMetadataObjectTypeCode39Code, AVMetadataObjectTypeCode39Mod43Code,
                          AVMetadataObjectTypeEAN13Code, AVMetadataObjectTypeEAN8Code, AVMetadataObjectTypeCode93Code, AVMetadataObjectTypeCode128Code,
                          AVMetadataObjectTypePDF417Code, AVMetadataObjectTypeQRCode, AVMetadataObjectTypeAztecCode];

for (AVMetadataObject *metadata in metadataObjects) {
    for (NSString *type in barCodeTypes) {
        if ([metadata.type isEqualToString:type])
        {
            barCodeObject = (AVMetadataMachineReadableCodeObject *)[_prevLayer transformedMetadataObjectForMetadataObject:(AVMetadataMachineReadableCodeObject *)metadata];
            highlightViewRect = barCodeObject.bounds;
            detectionString = [(AVMetadataMachineReadableCodeObject *)metadata stringValue];
            break;
        }
    }

    if (detectionString != nil)
    {
        [_session stopRunning];
        [self scanResult:detectionString];
        break;
    }

Answer 1

我发现了这个问题.Apple只需添加一个前导零即可将每个UPC-A条形码转换为EAN13.

解决方案是验证条形码是否为EAN13,并且如果字符串结果具有前导零,则可以安全地将其移除并获得UPC-A条形码.

if(detectionString!=nil){
    if([metadata.type isEqualToString:AVMetadataObjectTypeEAN13Code]){
        if ([detectionString hasPrefix:@"0"] && [detectionString length] > 1)
            detectionString = [detectionString substringFromIndex:1];
    }
}

链接到Apple技术说明:https://developer.apple.com/library/content/technotes/tn2325/_index.html#//apple_ref/doc/uid/DTS40013824-CH1-IS_UPC_A_SUPPORTED_

更多信息请访问:http://www-01.ibm.com/support/docview.wss？uid = post1R1002813

根据统一代码委员会,根据定义,以零开头的EAN-13条形码是12位UPC-A条形码.要遵循此规则,当扫描仪设备读取以零开头的EAN-13条形码时,它会丢弃前导0,将条形码截断为12位数,并将UPC-A(而不是EAN-13)指示符附加到标签上,在将标签传递给操作系统之前.因此,操作系统无法识别扫描仪设备传递给它的这个UPC-A标签最初是一个以零开头的EAN-13标签.