testALAssetsLibrary

• iOS开发中有时候会经常需要拍照和选取图片，拍照直接调用UIImageViewPicker就可以了，如若要自定义相机的话可以自己定义拍照页面，此先略过不讲。这篇文章只讲述如何自定义相册——利用系统的<AssetsLibrary/AssetsLibrary.h>框架。
• 首先第一步，当然是要导入<AssetsLibrary/AssetsLibrary.h>框架

导入框架

#import <AssetsLibrary/AssetsLibrary.h>
#import <AssetsLibrary/ALAsset.h>
#import <AssetsLibrary/ALAssetsLibrary.h>
#import <AssetsLibrary/ALAssetsGroup.h>
#import <AssetsLibrary/ALAssetRepresentation.h>

循环遍历ALAssetsLibrary，调用enumerateGroupsWithTypes的block。

    [_assetsLibrary enumerateGroupsWithTypes:ALAssetsGroupAll usingBlock:^(ALAssetsGroup *group, BOOL *stop) {
    if (group)
    {
        //NSLog(@"*****相册个数***%@",self.groupMutArr);
        [self.groupMutArr addObject:group];
        //每个相册的名字
        NSString *groupName = [group valueForProperty:ALAssetsGroupPropertyName];
        [self.groupName addObject:groupName];
        
        for (ALAssetsGroup *_group in self.groupMutArr)
        {
            [_group enumerateAssetsUsingBlock:^(ALAsset *result, NSUInteger index, BOOL *stop) {
                if (result)
                {
                    [self.imageArr addObject:result];
                    //NSLog(@"*****所有相册里的所有图片****%@",self.imageArr);
                    //UIImage *image = [UIImage imageWithCGImage: result.thumbnail];
                    //NSString *type=[result valueForProperty:ALAssetPropertyType];
                }
            }];
        }
    }
    
    [self.collectionView reloadData];
    
    } failureBlock:^(NSError *error) {
    NSLog(@"获取相册失败");
    }];

根据数据数组来定义collectionView，返回数组

    pragma mark - UICollectionViewDataSource
    - (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
    {
        NSMutableArray *testMutArr = [NSMutableArray array];
        ALAssetsGroup *testGroup = [self.groupMutArr objectAtIndex:section];
        [testGroup enumerateAssetsUsingBlock:^(ALAsset *result, NSUInteger index, BOOL *stop) {
            if (result)
            {
                [testMutArr addObject:result];
            }
        }];
        
        return testMutArr.count;
    }
    
    - (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
    {
        return self.groupMutArr.count;
    }
    
    - (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
    {
        YBTNFirstCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:TNFirstCell forIndexPath:indexPath];
        
        NSMutableArray *mutArr = [NSMutableArray array];
        ALAssetsGroup *testGroup = [self.groupMutArr objectAtIndex:indexPath.section];
        [testGroup enumerateAssetsUsingBlock:^(ALAsset *result, NSUInteger index, BOOL *stop) {
            if (result){
                [mutArr addObject:result];
            }}];
        
        ALAsset *result = [mutArr objectAtIndex:indexPath.item];
        UIImage *image = [UIImage imageWithCGImage: result.thumbnail];
        [cell setCellWithImage:image];
        return cell;
    }

项目截图如下：

截图

参考在此项目demo