UITableView expandable animated rows

gistfile1.m

#pragma mark - BTDurableView

@interface BTDurableView : UIView

@end


@implementation BTDurableView

//
// -----------------------------------------------------------------------------
- (void)setBackgroundColor:(UIColor *)backgroundColor
{
	
}

//
// -----------------------------------------------------------------------------
- (void)setBackgroundColorAlternative:(UIColor *)backgroundColor
{
	[super setBackgroundColor:backgroundColor];
}

@end


#pragma mark - BTTableViewCell

@interface BTTableViewCell : UITableViewCell

@property (nonatomic, strong) BTDurableView *innerBox;

@end


@implementation BTTableViewCell

//
// -----------------------------------------------------------------------------
- (instancetype)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier
{
	self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
	
	if (self) {
		self.innerBox = [[BTDurableView alloc] initWithFrame:CGRectZero];
		[self addSubview:self.innerBox];
		self.selectedBackgroundView = [[UIView alloc] initWithFrame:CGRectZero];
		self.selectedBackgroundView.backgroundColor = [UIColor colorWithHue:0 saturation:0 brightness:0 alpha:0.5];
	}
	
	return self;
}

//
// -----------------------------------------------------------------------------
- (void)layoutSubviews
{
	[super layoutSubviews];
	self.innerBox.frame = CGRectInset(self.bounds, 10, 10);
}

@end


#pragma mark - BTViewController

@interface BTViewController () <UITableViewDataSource, UITableViewDelegate>

@property (nonatomic, strong) UITableView *tableView;
@property (nonatomic, strong) NSMutableArray *expansion;

@end


@implementation BTViewController

NSString * const kCellID	= @"kCellID";
NSUInteger const kSections	= 3;

//
// -----------------------------------------------------------------------------
- (void)viewDidLoad
{
	[super viewDidLoad];
	
	self.expansion = [NSMutableArray array];
	
	while (self.expansion.count < kSections) {
		[self.expansion addObject:[NSMutableIndexSet indexSet]];
	}
	
	self.tableView = [[UITableView alloc] initWithFrame:CGRectZero style:UITableViewStylePlain];
	self.tableView.dataSource = self;
	self.tableView.delegate = self;
	self.tableView.tableFooterView = [[UIView alloc] initWithFrame:CGRectZero];
	self.tableView.separatorInset = UIEdgeInsetsZero;
	self.tableView.layoutMargins = UIEdgeInsetsZero;
	
	[self.tableView registerClass:[BTTableViewCell class] forCellReuseIdentifier:kCellID];
	
	[self.view addSubview:self.tableView];
}

//
// -----------------------------------------------------------------------------
- (void)viewWillLayoutSubviews
{
	self.tableView.frame = self.view.bounds;
}

//
// -----------------------------------------------------------------------------
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
	return kSections;
}

//
// -----------------------------------------------------------------------------
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
	switch (section) {
		case 0:
			return 3;
		case 1:
			return 7;
		case 2:
			return 11;
		default:
			return 0;
	};
}

//
// -----------------------------------------------------------------------------
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
	NSMutableIndexSet *indexSet = self.expansion[indexPath.section];
	return [indexSet containsIndex:indexPath.row] ? 132 : 44;
}

//
// -----------------------------------------------------------------------------
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
	BTTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:kCellID forIndexPath:indexPath];
	cell.separatorInset = UIEdgeInsetsZero;
	cell.layoutMargins = UIEdgeInsetsZero;
	[cell.innerBox setBackgroundColorAlternative:
		[UIColor colorWithHue:((CGFloat)(indexPath.section + 1) / [tableView numberOfSections])
				   saturation:(1 - (CGFloat)(indexPath.row + 1) / [tableView numberOfRowsInSection:indexPath.section])
				   brightness:0.8
					    alpha:0.5]];
	return cell;
}

//
// -----------------------------------------------------------------------------
- (CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section
{
	return 44;
}

//
// -----------------------------------------------------------------------------
- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section
{
	UIView *view = [[UIView alloc] initWithFrame:CGRectZero];
	view.backgroundColor =
	    [UIColor colorWithHue:((CGFloat)(section + 1) / [tableView numberOfSections])
				   saturation:0.5
				   brightness:0.8
					    alpha:1];
	
	return view;
}

//
// -----------------------------------------------------------------------------
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
	NSMutableIndexSet *indexSet = self.expansion[indexPath.section];
	
	if ([indexSet containsIndex:indexPath.row]) {
		[indexSet removeIndex:indexPath.row];
	} else {
		[indexSet addIndex:indexPath.row];
	}
	
	UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
	
	[tableView beginUpdates];
	[cell layoutSubviews];
	[tableView endUpdates];
	
	[tableView deselectRowAtIndexPath:indexPath animated:YES];
}

@end