iOS 系统识别相册里面的二维码

///系统识别相册二维码
+(NSString *)stringValueFrom:(UIImage *)image{
    ///系统识别二维码
    CIDetector *detector = [CIDetector detectorOfType:CIDetectorTypeQRCode context:nil options:@{CIDetectorAccuracy: CIDetectorAccuracyHigh}];
    // 取得识别结果
    NSArray *features = [detector featuresInImage:[CIImage imageWithCGImage:image.CGImage]];
    NSString *resultStr;
    if (features.count == 0) {
        return @"请检查图片是不是二维码";
    }
    for (int index = 0; index < [features count]; index ++) {
        CIQRCodeFeature *feature = [features objectAtIndex:index];
        resultStr = feature.messageString;
    }
    return resultStr;
}