如何获取存储在设备中的所有图像并将其显示为iPhone SDK中的图库

Question

I want to get all the images stored in the device and show them as gallery in my iPhone app. UIImagePickerController shows all the photos in thumbnail view and on selecting each photo we get the data of that particular selected image only, instead i want to get all the photos at one shot and show them as gallery. Is this possible, if yes please tell me how to do this. What is the use of AssetLibrary ?. Does it help what I need to achieve.If yes, please tell me how to achieve this using AssetLibrary.

Answer 1

An instance of ALAssetsLibrary provides access to the videos and photos that are under the control of the Photos application.

The library includes those that are in the Saved Photos album, those coming from iTunes, and those that were directly imported into the device. You use it to retrieve the list of all asset groups and to save images and videos into the Saved Photos album.

ELCImagePickerController is an Example project for getting all the photos in the iPhone Photo Album.

Answer 2

You can get all photos from device using Asset Library. I implemented this in my app

-(void)getAllPhotos{
   NSArray  *imageArray=[[NSArray alloc] init];
   NSMutableArray *mutableArray =[[NSMutableArray alloc]init];
    NSMutableArray* assetURLDictionaries = [[NSMutableArray alloc] init];

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

    void (^assetEnumerator)( ALAsset *, NSUInteger, BOOL *) = ^(ALAsset *result, NSUInteger index, BOOL *stop) {
        if(result != nil) {
            if([[result valueForProperty:ALAssetPropertyType] isEqualToString:ALAssetTypePhoto]) {
                [assetURLDictionaries addObject:[result valueForProperty:ALAssetPropertyURLs]];
               // NSLog(@"assestlibrarymurari%@",assetURLDictionaries);

                NSURL *url= (NSURL*) [[result defaultRepresentation]url];

                [library assetForURL:url
                         resultBlock:^(ALAsset *asset) {
                             UIImage *img = [UIImage imageWithCGImage:[[asset defaultRepresentation] fullScreenImage]];
                             if(img){
                                 [mutableArray addObject:img];
                             }
//                                 [mutableArray addObject:[UIImage imageWithCGImage:[[asset defaultRepresentation] fullScreenImage]]];

                             if ([mutableArray count]==count)
                             {
                                 imageArray=[[NSArray alloc] initWithArray:mutableArray];
                                 [self allPhotosCollected:imageArray];
                             }
                         }
                        failureBlock:^(NSError *error){ NSLog(@"operation was not successfull!"); } ];

            }
        }
    };

    NSMutableArray *assetGroups = [[NSMutableArray alloc] init];

    void (^ assetGroupEnumerator) ( ALAssetsGroup *, BOOL *)= ^(ALAssetsGroup *group, BOOL *stop) {
        if(group != nil) {
            [group enumerateAssetsUsingBlock:assetEnumerator];
            [assetGroups addObject:group];
            NSLog(@"AssetGroup%@",assetGroups);
            count=[group numberOfAssets];
        }
    };

    assetGroups = [[NSMutableArray alloc] init];

    [library enumerateGroupsWithTypes:ALAssetsGroupAll
                           usingBlock:assetGroupEnumerator
                         failureBlock:^(NSError *error) {NSLog(@"There is an error");}];


}

call this method in ViewDidLoad or where you need. I hope this will help you.