I prefer to use UITableView to create table with 2 level hierarchy like this picture. Everytimes user tap on header, content is collapse or expand. After 3 days research, I found that there are 2 technical:
1.custom UITableViewCell with another table in itself
2.using section header view.
Now I decide to use the second. And because UITableView does not re-use section view (although UITableView contain 2 private variable: _reusableHeaderViews & _reusableFooterViews:), I created some custom methods to do this task. Every gone okay, except 1 bug: when I using method reloadSections:withRowAnimation with UITableViewRowAnimationFade, the header view become blank view.
Here is my code:
#import "MasterViewController.h"
@interface MasterViewController ()
//remember current section
@property (assign, nonatomic) NSInteger curSession;
@property (strong, nonatomic) NSMutableDictionary *reusableHeaderViews;
@end
@implementation MasterViewController
@synthesize reusableHeaderViews = _reusableHeaderViews;
@synthesize tableView = _tableView;
@synthesize curSession = _curSession;
@synthesize detailViewController = _detailViewController;
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
self.title = NSLocalizedString(@"Master", @"Master");
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
self.curSession = -1;
}
- (void)viewDidUnload
{
[super viewDidUnload];
// Release any retained subviews of the main view.
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
}
//method for adding header view into reuse-array
- (void)registerHeaderView:(UITableViewCell *)headerView forReuseIdentifier:(NSString *)reuseIdentifier
{
NSMutableDictionary *reusableDictionary = [self reusableHeaderViews];
if (reusableDictionary == nil)
{
reusableDictionary = [[NSMutableDictionary alloc] init]; //creates a storage dictionary if one doesn’t exist
self.reusableHeaderViews = reusableDictionary;
}
NSMutableArray *arrayForIdentifier = [[self reusableHeaderViews] objectForKey:reuseIdentifier];
if (arrayForIdentifier == nil)
{
//creates an array to store views sharing a reuse identifier if one does not exist
arrayForIdentifier = [[NSMutableArray alloc] init];
[reusableDictionary setObject:arrayForIdentifier forKey:reuseIdentifier];
}
[arrayForIdentifier addObject:headerView];
}
//get header view in reuse-array
- (UITableViewCell *)reuseableHeaderForIdentifier:(NSString *)reuseIdentifier
{
NSMutableArray *arrayOfViewsForIdentifier = [[self reusableHeaderViews] objectForKey:reuseIdentifier];
if (arrayOfViewsForIdentifier == nil)
{
return nil; //We don’t have any of this kind!
}
NSInteger indexOfAvailableHeaderView = [arrayOfViewsForIdentifier indexOfObjectPassingTest:^BOOL(id obj, NSUInteger idx, BOOL *stop)
{
//If my view doesn’t have a superview, it’s not on-screen.
return ![obj superview];
}];
if (indexOfAvailableHeaderView != NSNotFound)
{
UITableViewCell *headerView = [arrayOfViewsForIdentifier objectAtIndex:indexOfAvailableHeaderView];
return headerView; //Success!
}
return nil;
}
#pragma mark - Table View
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 15;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
if (_curSession == section)
return section;
return 0;
}
- (UIView*) tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section
{
static NSString *headerReuseIdentifier = @"Header";
UITableViewCell *cell = [self reuseableHeaderForIdentifier:headerReuseIdentifier];
if(cell == nil)
{
//Didn’t locate a reusable
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@""];
[self registerHeaderView:cell forReuseIdentifier:headerReuseIdentifier];
UITapGestureRecognizer *tapGR = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(openSection:)];
tapGR.numberOfTapsRequired = 1;
[cell addGestureRecognizer:tapGR];
cell.backgroundColor = [UIColor redColor];
}
cell.tag = section;
cell.textLabel.text = [NSString stringWithFormat:@"Section title %i", section];
return cell;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
}
cell.textLabel.text = [NSString stringWithFormat:@"Row %i - section %i", indexPath.row, indexPath.section];
return cell;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
}
- (void) openSection:(id)sender
{
NSInteger section = [[(UITapGestureRecognizer*)sender view] tag];
if(_curSession == -1)
{
_curSession = section;
[_tableView reloadSections:[NSIndexSet indexSetWithIndex:_curSession] withRowAnimation:UITableViewRowAnimationFade];
}
else if(_curSession == section)
{
_curSession = -1;
[_tableView reloadSections:[NSIndexSet indexSetWithIndex:section] withRowAnimation:UITableViewRowAnimationFade];
}
else if(_curSession != section)
{
NSInteger temp = _curSession;
_curSession = -1;
[_tableView reloadSections:[NSIndexSet indexSetWithIndex:temp] withRowAnimation:UITableViewRowAnimationFade];
_curSession = section;
[_tableView reloadSections:[NSIndexSet indexSetWithIndex:section] withRowAnimation:UITableViewRowAnimationFade];
}
}
@end
