iOS–app自定义相册–从自定义的相册中获取图片详解手机开发

一.获取单张图片

思路:

• 1.利用UIImagePickerController可以从系统自带的App(照片/相机)中获得图片
• 2.设置代理,遵守代理协议
  • 注意这个UIImagePickerController类比较特殊,需要遵守两个代理协议

    @interface ViewController () <UIImagePickerControllerDelegate, UINavigationControllerDelegate>

• 3.实现代理的方法didFinishPickingMediaWithInfo

- (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]; }

二.获取多张图片

思路:

• 导入头文件#import <Photos/Photos.h>
• PHAsset : 一个资源, 比如一张图片/一段视频
• PHAssetCollection : 一个相簿
• PHImageManager 图片管理者,是单例,发送请求才能从asset获取图片
• PHImageRequestOptions图片请求选项
• 注意:这个类是iOS8开始推广,iOS9开始废弃之前的方法
  系统适配iOS8之前,用下面这个库里面的API

  #import <AssetsLibrary/AssetsLibrary.h>

1.获得所有相簿的原图

- (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]; }

2.获得所有相簿中的缩略图

- (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]; }

3.遍历相册

/** 
 *  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); }]; } }