iOS save the image (video) to album

1, C language function manner

Note: UIImageWriteToSavedPhotosAlbum method must implement the proxy method, otherwise it will collapse.

// Parameter 1: Picture Object
 // Parameter 2: successful method of binding target
 // Parameter 3: After successfully calling the method
 // Parameter 4: need to pass information (parameters after a successful method call) 
UIImageWriteToSavedPhotosAlbum (self.imageView.image , Self, @selector (Image: didFinishSavingWithError: contextInfo :), nil);
 #pragma Mark - <save to album> 
- ( void ) Image: (UIImage *) Image didFinishSavingWithError: (NSError *) error contextInfo :( void * ) contextInfo { 
    NSString * MSG = nil;
     IF (error) { 
        MSG = @ " save image failed " ; 
    } the else { 
        MSG = @ "Save picture success " ; 
    } 
}

Method 2: Use framework implemented Photos

2.1 Photos01- basic understanding

PHAsset: a PHAsset the object represents a picture album or a video
PHAssetCollection: a PHAssetCollection target represents an album

If we want to save the image to the camera roll [], we must first ensure PHAsset add a new object, how to operate these objects? Nothing but these objects CRUD.

PHAsset 一个PHAsset对象就代表相册中的一张图片或者一个视频
CRUD PHAssetChangeRequest including pictures / video-related changes in operations

Charles [PHAsset fetchAssets ...];

PHAssetCollection 一个PHAssetCollection 对象就代表一个相册

CRUD PHAssetCollectionChangeRequest album includes all modifications related to the operation

check [PHAssetCollection fetchAssetCollectionsContainingAsset:...];

2.2 Photos02- save the image to your camera roll

// save the picture to the camera roll] [ 
    /// asynchronous modify operation 
    [[PHPhotoLibrary sharedPhotoLibrary] performChanges: ^ { 
        [PHAssetChangeRequest creationRequestForAssetFromImage: self.imageView.image]; 
    } CompletionHandler: ^ (BOOL Success, the NSError * _Nullable error) {
         IF (error) { 
            NSLog ( @ " % @ " , @ " save failed " ); 
        } the else { 
            NSLog ( @ " % @ " , @ " saved successfully " ); 
        } 
    }];

2.3 Photos03- create a new album

* Error = NSError nil; 
    [[PHPhotoLibrary sharedPhotoLibrary] performChangesAndWait: ^ {
         // get app name 
        
        NSString * title = [NSBundle mainBundle] .infoDictionary [(__ Bridge NSString * ) kCFBundleNameKey];
         // create a custom album [] 
        [PHAssetCollectionChangeRequest creationRequestForAssetCollectionWithTitle: title]; 
    } error: & error];

2.4 Photos04- inquiry album

NSString *title = [NSBundle mainBundle].infoDictionary[(__bridge NSString*)kCFBundleNameKey];
    //查询所有【自定义相册】
    PHFetchResult<PHAssetCollection *> *collections = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeAlbum subtype:PHAssetCollectionSubtypeAlbumRegular options:nil];
    PHAssetCollection *createCollection = nil;
    for (PHAssetCollection *collection in collections) {
        if ([collection.localizedTitle isEqualToString:title]) {
            createCollection = collection;
            break;
        }
    }
if(createCollection == nil) {
         // this is not the album corresponding to app created
         // Create custom albums [a] 
        the NSError * error = nil; 
        __block NSString * createCollectionID = nil; 
        [[PHPhotoLibrary sharedPhotoLibrary] performChangesAndWait: ^ {
             // Create a custom albums] [ 
           createCollectionID = [PHAssetCollectionChangeRequest creationRequestForAssetCollectionWithTitle: title] .placeholderForCreatedAssetCollection.localIdentifier; 
        } error: & error]; 
        createCollection = [PHAssetCollection fetchAssetCollectionsWithLocalIdentifiers:@[createCollectionID] options:nil].firstObject;
    }
    NSLog(@"%@",createCollection);

2.5 Photos05- save the image to a custom album

// 1. First save the image to the camera roll [] 
    /// synchronized modify operation 
    NSError * error = nil; 
    __block PHObjectPlaceholder * placeholder = nil; 
    [[PHPhotoLibrary sharedPhotoLibrary] performChangesAndWait: ^ { 
       placeholder =   [PHAssetChangeRequest creationRequestForAssetFromImage: self.imageView .image] .placeholderForCreatedAsset; 
    } error: & error];
     IF (error) { 
        NSLog ( @ " save failed " );
         return ; 
    } 
    // 2. has a customized album] [ 
    PHAssetCollection * assetCollection =self.createCollection;
     IF (assetCollection == nil) { 
        NSLog ( @ " Create Album failed " ); 
    } 
    // 3. just saved to the Camera Roll] [pictures inside references to the custom album] [ 
    [[PHPhotoLibrary sharedPhotoLibrary] performChangesAndWait: ^ { 
        PHAssetCollectionChangeRequest * requtes = [PHAssetCollectionChangeRequest changeRequestForAssetCollection: assetCollection]; 
        [requtes addAssets: @ [placeholder]]; 
    } error: & error];
     IF (error) { 
        NSLog ( @ " save image failed " ); 
    } the else {
        NSLog (@ " Save Picture Success " ); 
    }