ios 相册操作 ALAssetsLibrary

ios 相册操作 ALAssetsLibrary

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www.BkJia.Com 网友分享于： 2015-01-17 04:01:45 浏览数30170次

ios 相册操作 ALAssetsLibrary

1.ALAssetsLibrary 实例为我们提供了获取相册(照片app)中的图片和视频的功能。在ios8 photos framework代替了ALAssetsLibrary。

在使用ALAssetsLibrary时，我们需要申明它的实例。

ALAssetsLibrary* library = [[ALAssetsLibrary alloc] init];

2. 迭代获取相册ALAssetsGroup：

- (void)enumerateGroupsWithTypes:(ALAssetsGroupType)types
usingBlock:(ALAssetsLibraryGroupsEnumerationResultsBlock)enumerationBlock
failureBlock:(ALAssetsLibraryAccessFailureBlock)failureBlock

ALASSetsGroupType: 类型 ALAssetsGroupLibrary：从iTunes 来的相册内容（如本身自带的向日葵照片）。ALAssetsGroupAlbum：设备自身产生或从iTunes同步来的照片，但是不包括照片流跟分享流中的照片。(例如从各个软件中保存下来的图片)ALAssetsGroupEvent 相机接口事件产生的相册

ALAssetsGroupFaces 脸部相册（具体不清楚）

ALAssetsGroupSavedPhotos 相机胶卷照片

ALAssetsGroupPhotoStream 照片流

ALAssetsGroupAll 除了ALAssetsGroupLibrary上面所的内容。

ALAssetsLibraryGroupsEnumerationResultsBlock

ALAssetsLibraryGroupsEnumerationResultsBlock listGroupBlock = ^(ALAssetsGroup *group, BOOL *stop) {
ALAssetsFilter *onlyPhotosFilter = [ALAssetsFilter allPhotos];
[group setAssetsFilter:onlyPhotosFilter];
if ([group numberOfAssets] > 0)
{
[self.imageGroup addObject:group];
}
else
{
[self.tableView performSelectorOnMainThread:@selector(reloadData) withObject:nil waitUntilDone:NO];
}
};

上面就是迭代AlAssetsGroup的block。每迭代一次就把相应的AlAssetsGroup保存在一个可变的数组之中。AlAssetsGroup中的一些属性表明了这个相册的特征。比如：

posterImage 相册的缩略图

numberOfAssets 相册中照片的数量

valueForProperty 通过NSString获取一些属性，有以下的属性

NSString*constALAssetsGroupPropertyName;NSString*constALAssetsGroupPropertyType;NSString*constALAssetsGroupPropertyPersistentID; （唯一标识ID）NSString*constALAssetsGroupPropertyURL;（唯一标识URL

#import "AssetsViewController.h"
#import
@interface AssetsViewController ()

@property  (nonatomic, strong)  ALAssetsLibrary *assetsLibrary;
@property  (nonatomic, strong)  UITableView *tableView;
@property  (nonatomic, strong)  NSMutableArray *imageGroup;
@end

@implementation AssetsViewController

- (ALAssetsLibrary *)assetsLibrary
{
if (!_assetsLibrary) {
_assetsLibrary = [[ALAssetsLibrary alloc] init];
}
return _assetsLibrary;
}

- (NSMutableArray *)imageGroup
{
if (!_imageGroup) {
_imageGroup = [[NSMutableArray alloc] initWithCapacity:0];
}
return _imageGroup;
}

- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.

[self.imageGroup removeAllObjects];

UITableView *tableView = [[UITableView alloc] initWithFrame:self.view.bounds style:UITableViewStylePlain];
[self.view addSubview:tableView];
tableView.delegate = self;
tableView.dataSource = self;

ALAssetsLibraryGroupsEnumerationResultsBlock listGroupBlock = ^(ALAssetsGroup *group, BOOL *stop) {
ALAssetsFilter *onlyPhotosFilter = [ALAssetsFilter allPhotos];
[group setAssetsFilter:onlyPhotosFilter];
if ([group numberOfAssets] > 0)
{
[self.imageGroup addObject:group];
}
else
{
[self.tableView performSelectorOnMainThread:@selector(reloadData) withObject:nil waitUntilDone:NO];
}
};

NSUInteger groupTypes = ALAssetsGroupAll ;

[self.assetsLibrary enumerateGroupsWithTypes:groupTypes usingBlock:listGroupBlock failureBlock:^(NSError *error) {
NSLog(@"Group not found!\n");
}];
}

- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return self.imageGroup.count;
}

-  (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *cellName = @"name";
UITableViewCell *cell =  [tableView dequeueReusableCellWithIdentifier:cellName];
if (!cell) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:cellName];
}

ALAssetsGroup *group = [self.imageGroup objectAtIndex:indexPath.row];
UIImage *postImage = [UIImage imageWithCGImage:[group posterImage]];

cell.imageView.image =  postImage;
cell.textLabel.text = [group valueForProperty:ALAssetsGroupPropertyName];;
cell.detailTextLabel.text = [@(group.numberOfAssets) stringValue];
return cell;
}