PhotoKit 监听相册变化

功能实现：

实时监听相册视频文件的增删（文末附GitHub地址）；

1.导入库:

#import <Photos/Photos.h>

2.遵守协议:

<PHPhotoLibraryChangeObserver>

3.添加对象：

@property (nonatomic, strong) PHFetchResult *assetsFetchResults;

4.初始化工具类,注册监听,并主动调用一下获取视频的方法（因为第一次启动，监听对象缺少参照）:

- (void)startManager { //注册相册的监听
      dispatch_async(album_queue(), ^{
        self.dataSource = [[NSMutableArray alloc] init];
        self.assetsFetchResults = [[PHFetchResult alloc] init];
        [[PHPhotoLibrary sharedPhotoLibrary] registerChangeObserver:self];
        [self getAlbumVideoWithBehaviorType:ALBUMVIDEOBEHAVIOR_GETALL PHObjectsArr:nil];
    });
}

5.实现监听的方法：

- (void)photoLibraryDidChange:(PHChange *)changeInstance {
     //注：监听到动作之后要在主线程做处理    
     dispatch_async(dispatch_get_main_queue(), ^{
        // 监听相册视频发生变化
        PHFetchResultChangeDetails *collectionChanges = [changeInstance changeDetailsForFetchResult:self.assetsFetchResults];
        if (collectionChanges) {
            if ([collectionChanges hasIncrementalChanges]) {
                //监听相册视频的增删
                //增加了
                if (collectionChanges.insertedObjects.count > 0) {
                    NSMutableArray *mArr = [[NSMutableArray alloc] initWithArray:collectionChanges.insertedObjects];
                    [self getAlbumVideoWithBehaviorType:ALBUMVIDEOBEHAVIOR_INSTER PHObjectsArr:mArr];
                }
                //删除了
                if (collectionChanges.removedObjects.count > 0) {                    
                    NSMutableArray *mArr = [[NSMutableArray alloc] initWithArray:collectionChanges.removedObjects];
                    [self getAlbumVideoWithBehaviorType:ALBUMVIDEOBEHAVIOR_REMOVE PHObjectsArr:mArr];
                }
                /*监听完一次更新一下监听对象*/
                self.assetsFetchResults = [PHAsset fetchAssetsWithMediaType:PHAssetMediaTypeVideo options:[self getFetchPhotosOptions]];
            }
        }
    });
}

6.拿到监听数据，操作添加数据源:

//筛选的规则和范围
- (PHFetchOptions *)getFetchPhotosOptions{
    PHFetchOptions *allPhotosOptions = [[PHFetchOptions alloc]init];
    //排序的方式为：按时间排序
    allPhotosOptions.sortDescriptors = @[[NSSortDescriptor sortDescriptorWithKey:@"creationDate" ascending:YES]];
    return allPhotosOptions;
}

- (void)getAlbumVideoWithBehaviorType:(AlbumVideoBehaviorType)type PHObjectsArr:(NSArray *)phobjectsArr;{  
    @synchronized(self) {
        if (type == ALBUMVIDEOBEHAVIOR_GETALL) {      
            self.assetsFetchResults = [PHAsset fetchAssetsWithMediaType:PHAssetMediaTypeVideo options:[self getFetchPhotosOptions]];            
            if (!self.assetsFetchResults.count) {
                [self.dataSource removeAllObjects];
                [[NSNotificationCenter defaultCenter] postNotificationName:RefreshAlbumUINotification object:nil];
                return;
            }
            [self.dataSource removeAllObjects];
        }        
        for (PHAsset *videoAsset in type == ALBUMVIDEOBEHAVIOR_GETALL ? self.assetsFetchResults : phobjectsArr) {            
            [[PHImageManager defaultManager] requestPlayerItemForVideo:videoAsset options:nil resultHandler:^(AVPlayerItem * _Nullable playerItem, NSDictionary * _Nullable info) {                
                NSString *filePath = [info valueForKey:@"PHImageFileSandboxExtensionTokenKey"];
                if (filePath && filePath.length > 0) {
                    NSArray *lyricArr = [filePath componentsSeparatedByString:@";"];
                    NSString *privatePath = [lyricArr lastObject];
                    if (privatePath.length > 8) {
                        NSString *videoPath = [privatePath substringFromIndex:8];
                        if (videoPath && videoPath.length > 0) {
                            NSArray *fieldArr = [videoPath componentsSeparatedByString:@"/"];
                            if (fieldArr != nil && ![fieldArr isKindOfClass:[NSNull class]] && fieldArr.count != 0) {                               
                                if (type == ALBUMVIDEOBEHAVIOR_REMOVE) {
                                    if (self.dataSource.count > 0) {
                                        /**数组的安全遍历*/
                                        NSArray *arr = [NSArray arrayWithArray:self.dataSource];
                                        for (VideoModel *model in arr) {
                                            if ([model.videoName isEqualToString:[fieldArr lastObject]]) {
                                                [self.dataSource removeObject:model];
                                                [self cleanImgWithUseless:model.videoImgPath];
                                            }
                                        }
                                    }
                                } else {
                                    VideoModel *model = [[VideoModel alloc] init];
                                    model.videoPath = videoPath;
                                    model.videoName = [fieldArr lastObject];
                                    model.videoSize = [SandBoxHelper fileSizeForPath:videoPath];
                                    model.videoImgPath = [self saveImg:[UIImage getThumbnailImage:videoPath] withVideoMid:model.videoName];
                                    model.videoAsset = videoAsset;
                                    [self.dataSource addObject:model];
                                }                              
                                NSLog(@"相册视频数量为 = %ld", self.dataSource.count);                                
                                dispatch_async(dispatch_get_main_queue(), ^{ //添加完一个数据，通知页面刷新
                                    [[NSNotificationCenter defaultCenter] postNotificationName:RefreshAlbumUINotification object:nil];                                    
                                });
                            }
                        }
                    }
                }
            }];
        }
    }
}

7.关闭工具的时候注销一下监听:

- (void)stopManager { //注销相册的监听
    dispatch_async(dispatch_queue_create(0, 0), ^{
        [[PHPhotoLibrary sharedPhotoLibrary] unregisterChangeObserver:self];
    });
}

将以上代码封装成工具后如何使用：

因为工具的启动是在子线程里完成的，程序启动的时候启动工具

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
 
    [self getAlbumRightAndSource]; //获取相册权限和数据 
}

- (void)getAlbumRightAndSource{
    PHAuthorizationStatus author = [PHPhotoLibrary authorizationStatus];
    if (author == PHAuthorizationStatusNotDetermined || author == PHAuthorizationStatusRestricted || author == PHAuthorizationStatusDenied) {
        PVRLog(@" 用户尚未做出选择这个应用程序的问候||此应用程序没有被授权访问的照片数据 || 用户已经明确否认了这一照片数据的应用程序访问");
    }else{
        [[AlbumManager shared] startManager];
        return;
    }
    if ([PHPhotoLibrary authorizationStatus] == PHAuthorizationStatusNotDetermined) {
        [PHPhotoLibrary requestAuthorization:^(PHAuthorizationStatus status) {
            if (status == PHAuthorizationStatusAuthorized) {
                [[AlbumManager shared] startManager];
                PVRLog(@"相册授权开启，启动AlbumManager");
            }
        }];
    }
}

代码地址：

GitHub:https://github.com/YZQ-Nine/GetLocalVideo