级别：★★☆☆☆
标签：「iOS CIDetector」「CIQRCodeFeature」「识别相册图片」
作者： Xs·H
审校： QiShare团队
接上篇 iOS 扫描二维码/条形码，本文补充介绍扫描相册图片上二维码的实现方式。先看看QiQRCode中的示例效果：
iOS 扫描相册图片上二维码效果
iOS 8之后，可以结合CIDetector使用CIQRCodeFeature实现扫描相册图片上二维码的功能。具体实现过程如下：
1、遵守协议
@interface QiCodeManager () <UIImagePickerControllerDelegate, UINavigationControllerDelegate>
2、打开相册
- (void)presentPhotoLibraryWithRooter:(UIViewController *)rooter callback:(nonnull void (^)(NSString * _Nonnull))callback {
_callback = callback;
UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];
imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
// imagePicker.allowsEditing = YES;
imagePicker.delegate = self;
[rooter presentViewController:imagePicker animated:YES completion:nil];
}
3、实现代理
// UIImagePickerControllerDelegate
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<UIImagePickerControllerInfoKey,id> *)info {
UIImage *pickedImage = info[UIImagePickerControllerEditedImage] ?: info[UIImagePickerControllerOriginalImage];
CIImage *detectImage = [CIImage imageWithData:UIImagePNGRepresentation(pickedImage)];
CIDetector *detector = [CIDetector detectorOfType:CIDetectorTypeQRCode context:nil options:@{CIDetectorAccuracy: CIDetectorAccuracyLow}];
CIQRCodeFeature *feature = (CIQRCodeFeature *)[detector featuresInImage:detectImage options:nil].firstObject;
[picker dismissViewControllerAnimated:YES completion:^{
if (feature.messageString) {
[self handleCodeString:feature.messageString];
}
}];
}
4、透传给业务
- (void)handleCodeString:(NSString *)codeString {
if (_autoStop) {
[self stopScanning];
}
if (_callback) {
_callback(codeString);
}
}
5、业务调用方式
// 创建“相册”按钮
UIBarButtonItem *photoItem = [[UIBarButtonItem alloc] initWithTitle:@"相册" style:UIBarButtonItemStylePlain target:self action:@selector(photo:)];
self.navigationItem.rightBarButtonItem = photoItem;
// 实现“相册”按钮方法
- (void)photo:(id)sender {
__weak typeof(self) weakSelf = self;
[_codeManager presentPhotoLibraryWithRooter:self callback:^(NSString * _Nonnull code) {
[weakSelf performSegueWithIdentifier:@"showCodeGeneration" sender:code];
}];
}
上述代码中的核心步骤是第3步—实现代理。
我们通过UIImagePickerController拿到image后，使用CIDetector和CIQRCodeFeature读取image上的信息，最终得到的feature.messageString就是二维码的字符串信息。
示例源码QiQRCode可从GitHub的QiShare开源库中获取。
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