iOS中获取系统相册中的图片实例

@interface ViewController () <UIImagePickerControllerDelegate, UINavigationControllerDelegate>

- (void)getImageFromIpc
{
  // 1.判断相册是否可以打开
  if (![UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary]) return;
  // 2. 创建图片选择控制器
  UIImagePickerController *ipc = [[UIImagePickerController alloc] init];
  /**
   typedef NS_ENUM(NSInteger, UIImagePickerControllerSourceType) {
   UIImagePickerControllerSourceTypePhotoLibrary, // 相册
   UIImagePickerControllerSourceTypeCamera, // 用相机拍摄获取
   UIImagePickerControllerSourceTypeSavedPhotosAlbum // 相簿
   }
   */
  // 3. 设置打开照片相册类型(显示所有相簿) 
  ipc.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
  // ipc.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;
  // 照相机
  // ipc.sourceType = UIImagePickerControllerSourceTypeCamera;
  // 4.设置代理
  ipc.delegate = self;
  // 5.modal出这个控制器
  [self presentViewController:ipc animated:YES completion:nil];
}

#pragma mark -- <UIImagePickerControllerDelegate>--
// 获取图片后的操作
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info
{
  // 销毁控制器
  [picker dismissViewControllerAnimated:YES completion:nil];

  // 设置图片
  self.imageView.image = info[UIImagePickerControllerOriginalImage];
}

#import <AssetsLibrary/AssetsLibrary.h>

- (void)getOriginalImages
{
  // 获得所有的自定义相簿
  PHFetchResult<PHAssetCollection *> *assetCollections = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeAlbum subtype:PHAssetCollectionSubtypeAlbumRegular options:nil];
  // 遍历所有的自定义相簿
  for (PHAssetCollection *assetCollection in assetCollections) {
    [self enumerateAssetsInAssetCollection:assetCollection original:YES];
  }

  // 获得相机胶卷
  PHAssetCollection *cameraRoll = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeSmartAlbum subtype:PHAssetCollectionSubtypeSmartAlbumUserLibrary options:nil].lastObject;
  // 遍历相机胶卷,获取大图
  [self enumerateAssetsInAssetCollection:cameraRoll original:YES];
}

- (void)getThumbnailImages
{
  // 获得所有的自定义相簿
  PHFetchResult<PHAssetCollection *> *assetCollections = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeAlbum subtype:PHAssetCollectionSubtypeAlbumRegular options:nil];
  // 遍历所有的自定义相簿
  for (PHAssetCollection *assetCollection in assetCollections) {
    [self enumerateAssetsInAssetCollection:assetCollection original:NO];
  }
  // 获得相机胶卷
  PHAssetCollection *cameraRoll = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeSmartAlbum subtype:PHAssetCollectionSubtypeSmartAlbumUserLibrary options:nil].lastObject;
  [self enumerateAssetsInAssetCollection:cameraRoll original:NO];
}

/**
 * 遍历相簿中的所有图片
 * @param assetCollection 相簿
 * @param original    是否要原图
 */
- (void)enumerateAssetsInAssetCollection:(PHAssetCollection *)assetCollection original:(BOOL)original
{
  NSLog(@"相簿名:%@", assetCollection.localizedTitle);

  PHImageRequestOptions *options = [[PHImageRequestOptions alloc] init];
  // 同步获得图片, 只会返回1张图片
  options.synchronous = YES;

  // 获得某个相簿中的所有PHAsset对象
  PHFetchResult<PHAsset *> *assets = [PHAsset fetchAssetsInAssetCollection:assetCollection options:nil];
  for (PHAsset *asset in assets) {
    // 是否要原图
    CGSize size = original ? CGSizeMake(asset.pixelWidth, asset.pixelHeight) : CGSizeZero;

    // 从asset中获得图片
    [[PHImageManager defaultManager] requestImageForAsset:asset targetSize:size contentMode:PHImageContentModeDefault options:options resultHandler:^(UIImage * _Nullable result, NSDictionary * _Nullable info) {
      NSLog(@"%@", result);
    }];
  }
}