Classes/RootViewController.m

/*
     File: RootViewController.m 
 Abstract: n/a 
  Version: 1.2 
  
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*/
 
#import "AssetsDataIsInaccessibleViewController.h"
#import "AssetsList.h"
#import "FavoriteAssets.h"
#import "MapViewController.h"
#import "RootViewController.h"
 
@interface RootViewController ()
- (void)loadGroups;
@end
 
 
@implementation RootViewController
 
 
#pragma mark -
#pragma mark View lifecycle
 
-(void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];
    
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(assetsLibraryChanged:) name:ALAssetsLibraryChangedNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(favoriteAssetsChanged:) name:kFavoriteAssetsChanged object:nil];
    
    [self loadGroups];
}
 
- (void)loadGroups {
    
    if (!assetsLibrary) {
        assetsLibrary = [[ALAssetsLibrary alloc] init];
    }
    if (!groups) {
        groups = [[NSMutableArray alloc] init];
    } else {
        [groups removeAllObjects];
    }
    
    ALAssetsLibraryGroupsEnumerationResultsBlock listGroupBlock = ^(ALAssetsGroup *group, BOOL *stop) {
        
        if (group) {
            [groups addObject:group];
        } else {
            // Add the favorites group if it has any elements
            if (!favoriteAssets) {
                favoriteAssets = [[FavoriteAssets alloc] init];
            }
            if ([favoriteAssets count] > 0) {
                [groups addObject:favoriteAssets];
            }
            
            [self.tableView performSelectorOnMainThread:@selector(reloadData) withObject:nil waitUntilDone:NO];
        }
    };
    
    
    ALAssetsLibraryAccessFailureBlock failureBlock = ^(NSError *error) {
        AssetsDataIsInaccessibleViewController *assetsDataInaccessibleViewController = [[AssetsDataIsInaccessibleViewController alloc] initWithNibName:@"AssetsDataIsInaccessibleViewController" bundle:nil];
        
        NSString *errorMessage = nil;
        switch ([error code]) {
            case ALAssetsLibraryAccessUserDeniedError:
            case ALAssetsLibraryAccessGloballyDeniedError:
                errorMessage = @"The user has declined access to it.";
                break;
            default:
                errorMessage = @"Reason unknown.";
                break;
        }
        
        assetsDataInaccessibleViewController.explanation = errorMessage;
        [self presentViewController:assetsDataInaccessibleViewController animated:NO completion:nil];
        [assetsDataInaccessibleViewController release];
    };
    
    NSUInteger groupTypes = ALAssetsGroupAlbum | ALAssetsGroupEvent;
    [assetsLibrary enumerateGroupsWithTypes:groupTypes usingBlock:listGroupBlock failureBlock:failureBlock];
    
}
 
 
#pragma mark -
#pragma mark Table view data source
 
// Customize the number of sections in the table view.
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
    return 1;
}
 
 
// Customize the number of rows in the table view.
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    return ceil((float)groups.count / 2);
}
 
 
// Customize the appearance of table view cells.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    
    static NSString *CellIdentifier = @"Cell";
    
    AssetsGroupsTableViewCell *cell = (AssetsGroupsTableViewCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        [[NSBundle mainBundle] loadNibNamed:@"AssetsGroupsTableViewCell" owner:self options:nil];
        cell = tmpCell;
        tmpCell = nil;
    }
    
    cell.rowNumber = indexPath.row;
    cell.selectionDelegate = self;
    
    // Configure the cell.
    NSUInteger leftGroupIndex = indexPath.row * 2;
    NSUInteger rightGroupIndex = leftGroupIndex + 1;
    
    ALAssetsGroup *leftGroup = [groups objectAtIndex:leftGroupIndex];
    ALAssetsGroup *rightGroup = (rightGroupIndex < groups.count) ? [groups objectAtIndex:rightGroupIndex] : nil;
    
    if (leftGroup) {
        CGImageRef posterImageRef = [leftGroup posterImage];
        UIImage *posterImage = [UIImage imageWithCGImage:posterImageRef];
        [cell setLeftPosterImage:posterImage];
        [cell setLeftLabelText:[leftGroup valueForProperty:ALAssetsGroupPropertyName]];
    }
    if (rightGroup) {
        CGImageRef posterImageRef = [rightGroup posterImage];
        UIImage *posterImage = [UIImage imageWithCGImage:posterImageRef];
        [cell setRightPosterImage:posterImage];
        [cell setRightLabelText:[rightGroup valueForProperty:ALAssetsGroupPropertyName]];
        [cell rightPosterImageView].userInteractionEnabled = YES;
    } else {
        [cell setRightLabelText:@""];
        [cell setRightPosterImage:nil];
        [cell rightPosterImageView].userInteractionEnabled = NO;
    }
    
    return cell;
}
 
#pragma mark -
#pragma mark AssetsGroupsTableViewCellSelectionDelegate
- (void)assetsGroupsTableViewCell:(AssetsGroupsTableViewCell *)cell selectedGroupAtIndex:(NSUInteger)index {
    
    MapViewController *mapViewController = [[MapViewController alloc] initWithNibName:@"MapViewController" bundle:nil];
    
    id objectAtRow = [groups objectAtIndex:(cell.rowNumber * 2) + index];
    AssetsList *assetsList = [objectAtRow assetsList];
    mapViewController.assetsList = assetsList;
    mapViewController.favoriteAssets = favoriteAssets;
    
    [[self navigationController] pushViewController:mapViewController animated:YES];
    [mapViewController release];
    
}
 
#pragma mark -
#pragma mark Memory management
 
- (void)didReceiveMemoryWarning {
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];
    
    // Relinquish ownership any cached data, images, etc that aren't in use.
}
 
- (void)viewWillDisappear:(BOOL)animated {
    [groups removeAllObjects];
        
    [[NSNotificationCenter defaultCenter] removeObserver:self name:ALAssetsLibraryChangedNotification object:nil];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:kFavoriteAssetsChanged object:nil];
    
    [super viewWillDisappear:animated];
}
 
- (void)dealloc {
    [[NSNotificationCenter defaultCenter] removeObserver:self];
    [assetsLibrary release];
    [groups release];
    [favoriteAssets release];
 
    [super dealloc];
}
 
 
#pragma mark -
#pragma mark Change Notifications handlers
 
- (void)assetsLibraryChanged:(NSNotification *)notification {
    [self loadGroups];
}
 
- (void)favoriteAssetsChanged:(NSNotification *)notification {
    [self loadGroups];
}
 
@end