无法获取使用相机拍摄的图像文件名

Question

我正在尝试构建一个应用程序，可以使用相机拍摄并保存图片到图库。但是我无法获取图片的文件名。如果我从相机胶卷中选择图片，那么我就能够获取所选图片的文件名。但是当我在我的应用程序中使用相机拍摄照片时，它返回文件名“null”。以下是我使用UIImagePickerController保存和选择图库中图片的代码：

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{

    UIImage *chosenImage = [self scaleAndRotateImage:[info valueForKey:UIImagePickerControllerOriginalImage]];
    NSString *mediaType = info[UIImagePickerControllerMediaType];
       self.userProfileImage.image = chosenImage;

    if ([mediaType isEqualToString:(NSString *)kUTTypeImage]) {
        UIImage *image = info[UIImagePickerControllerOriginalImage];

        if (newMedia)
            UIImageWriteToSavedPhotosAlbum(image,
                                           self,
                                           @selector(image:finishedSavingWithError:contextInfo:),
                                           nil);
    }

    imageRotation=[NSString stringWithFormat:@"%f %f %f",acos (self.userProfileImage.transform.a), asin (self.userProfileImage.transform.b), atan2(self.userProfileImage.transform.b, self.userProfileImage.transform.a)];
    CGFloat angle = [(NSNumber *)[self.userProfileImage valueForKeyPath:@"layer.transform.rotation.z"] floatValue];
    NSLog(@"%f", angle);

    NSURL *referenceURL = [info objectForKey:UIImagePickerControllerReferenceURL];
    ALAssetsLibrary *assetLibrary = [ALAssetsLibrary new];

    [assetLibrary assetForURL:referenceURL
                  resultBlock:^(ALAsset *asset) {
                      ALAssetRepresentation *assetRep = [asset defaultRepresentation];
                     fileName = [assetRep filename];
                      NSLog(@"File name = %@", fileName);    
                  }

                 failureBlock:^(NSError *error) {
                     NSLog(@"%@", error);
                 }];

    [[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent];
    [[UIApplication sharedApplication] setStatusBarHidden:YES];
    [picker dismissViewControllerAnimated:YES completion:nil];
    imageChanged=TRUE;
}

这段代码是用来保存截图的

- (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo {
    UIAlertView *alert;
    //NSLog(@"Image:%@", image);
      if (error) {
        alert = [[UIAlertView alloc] initWithTitle:@"Error!"
                                           message:[error localizedDescription]
                                          delegate:nil
                                 cancelButtonTitle:@"OK"
                                 otherButtonTitles:nil];
        [alert show];

    }
}

我卡在了如何获取捕获图像的文件名这一点上。我的代码有什么问题吗？请给我提供任何更正或解决方案。非常感谢您的帮助。提前致谢。

- Sushil Sharma

Answer 1

以下是我如何获取使用UIImagePickerController选取的文件、视频或照片的文件名：

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
    @try {
        self.myinfo = info;
        DDLogDebug(@"MediaListView - Dismissing camera ui...");
        [self.cameraUI dismissViewControllerAnimated:YES completion:nil];

        mediaURL = [info objectForKey:UIImagePickerControllerMediaURL];
        DDLogDebug(@"MediaListView - Media url = %@", mediaURL);

        NSString *mediaType = [info objectForKey:UIImagePickerControllerMediaType];
        DDLogDebug(@"MediaListView - Selected mediaType: %@", mediaType);

        // This is a video
        if(mediaURL) {
            DDLogDebug(@"MediaListView - This is a video");

            // Just recorded video
            if (self.source == UIImagePickerControllerSourceTypeCamera) {
                DDLogDebug(@"MediaListView - This is a new video, saving to photos album...");

                // Save video before getting its name
                ALAssetsLibrary *library = [ALAssetsLibrary new];

                [library writeVideoAtPathToSavedPhotosAlbum:mediaURL completionBlock:^(NSURL *assetURL, NSError *error){
                    if (error) {
                        DDLogDebug(@"MediaListView - Failed to save the photo to photos album...");
                    } else {
                        DDLogDebug(@"MediaListView - Video saved to photos album...");

                        // Video saved, we can get its name
                        [self getNameFromUrl:assetURL];
                    }
                }];
            }
            else {
                DDLogDebug(@"MediaListView - This is an existing video, getting name...");
                // Get video name
                [self getNameFromUrl:[info objectForKey:UIImagePickerControllerReferenceURL]];
            }
        }
        // This is a photo
        else {
            DDLogDebug(@"MediaListView - This is a photo...");
            self.originalImage = (UIImage*)[info objectForKey:UIImagePickerControllerOriginalImage];

            // Just taken photo
            if (self.source == UIImagePickerControllerSourceTypeCamera) {
                DDLogDebug(@"MediaListView - This is a new photo, saving to photos album...");

                // Save photo to album
                ALAssetsLibrary *library = [ALAssetsLibrary new];

                [library writeImageToSavedPhotosAlbum:[self.originalImage CGImage]
                                          orientation:(ALAssetOrientation)[self.originalImage imageOrientation]
                                      completionBlock:^(NSURL *assetURL, NSError *error){
                    if (error) {
                        DDLogDebug(@"MediaListView - Failed to save the vide to photos album...");
                    } else {
                        DDLogDebug(@"MediaListView - Photo saved to photos album...");

                        // Get photo name
                        [self getNameFromUrl:assetURL];
                    }
                }];
            }
            else {
                DDLogDebug(@"MediaListView - This is an existing image, getting name...");
                // Get photo name
                [self getNameFromUrl:[info objectForKey:@"UIImagePickerControllerReferenceURL"]];
            }
        }
    }
    @catch (NSException *exception) {
        DDLogError(@"MediaListView - Exception in picker didFinishPickingMediaWithInfo");
        DDLogError(@"MediaListView - %@", [exception description]);
    }
}

- (void)getNameFromUrl(NSURL*)url {
    @try {
        DDLogDebug(@"MediaListView - GetNameFromUrl");

        ALAssetsLibraryAssetForURLResultBlock resultblock = ^(ALAsset *asset) {

            if (asset == nil) {
                DDLogError(@"MediaListView - SaveAssetData - asset is nil!");
                return;
            }

            DDLogDebug(@"MediaListView - SaveAssetData - Got asset data: %@", asset.description);
            ALAssetRepresentation *assetRep = [asset defaultRepresentation];

            NSString *fileName = [assetRep filename];
            DDLogDebug(@"MediaListView - SaveAssetData - File name = %@", fileName);
        };

        ALAssetsLibraryAccessFailureBlock failureblock  = ^(NSError *error) {
            DDLogError(@"MediaListView - SaveAssetData - Failed to get name%@", error);
        };

        ALAssetsLibrary *library = [ALAssetsLibrary new];
        [library assetForURL:url resultBlock:resultblock failureBlock:failureblock];
    }
    @catch (NSException *exception) {
        DDLogError(@"MediaListView - Exception in saveAssetData");
        DDLogError(@"MediaListView - %@", [exception description]);
    }
}

- Olcay Ertaş

---

即使将取消选择器移动到代码块的第一行，它仍然无法正常工作。 - Sushil Sharma

Answer 2

如何获取使用iOS Swift相机拍摄照片的路径

你所拍摄的照片尚未保存，因此还没有名称。在获取该图片的路径之前，你需要先将其保存。这就是为什么它返回 nil 的原因。

- Priyanka