In iOS, AssetsLibrary is used to support multi-graph selection.

The AssetsLibrary framework provides the ALAssetsLibrary class to help us access the photos and videos managed by the album program. See this for official documentation.

If (! Self. assetsLibrary ){
_ AssetsLibrary = [[ALAssetsLibrary alloc] init];
}

Through this framework, we can get the album list:
[_ AssetsLibrary enumerateGroupsWithTypes: ALAssetsGroupAll usingBlock: ^ (ALAssetsGroup * group, BOOL * stop ){
If (group ){
[Self. groupArray addObject: group];
}
} FailureBlock: ^ (NSError * error ){
NSLog (@ "Group not found! N ");
}];

By clicking on each album, we can access the photo list in the album:
# Pragma mark-

-(Void) getImages
{
If (! Self. assetsArray ){
_ AssetsArray = [[NSMutableArray alloc] init];
}

If (! Self. assetsLibrary ){
_ AssetsLibrary = [[ALAssetsLibrary alloc] init];
}

@ Autoreleasepool {
[Self. assetsGroup enumerateAssetsUsingBlock: ^ (ALAsset * result, NSUInteger index, BOOL * stop ){
If (result ){
TTAsset * ttAsset = [[TTAsset alloc] initWithAsset: result];
[Self. assetsArray addObject: ttAsset];
[TtAsset release], ttAsset = nil;
}
}];
}

[Self. tableView reloadData];
}

Finally, we can customize the display style through the custom Cell, such as the selected effect and the selected list at the bottom.