Accordion style tableview without using sections - iphone

Question

I am interning for the summer on an iOS native app development team. They gave me a task of accomplishing removing/inserting cells in a tableview without using sections. I am struggling with the task if anyone could take a look at the code and try to help me out id be much appreciated. I am getting some removals and disappearances but it is not staying consistent, and it is adding cells that are already visible. (consistency in the sense that once i insert rows, row 3 is now row 5, and my modulo arithmetic gets thrown off.
I am very new to objective c so any advice / help would be much appreciated.
#implementation MasterViewController
NSMutableArray * levels;
NSMutableArray * array;
NSMutableIndexSet * expandedSections;
NSMutableDictionary * dict;
-(BOOL) loadFiles{
// NSFileManager * fileManager = [NSFileManager defaultManager];
if (!expandedSections) {
expandedSections = [[NSMutableIndexSet alloc]init];
}
array = [[NSMutableArray alloc]init];
levels = [[NSMutableArray alloc]init];
for (int i=0; i<20; i++) {
NSString * temp = [[NSString alloc]initWithFormat:#"This is row : %i ", i];
[array addObject:temp];
}
for (int i=0; i<20; i++) {
NSNumber * temp = [[NSNumber alloc]initWithInt:i];
[levels addObject:temp];
}
dict = [[NSMutableDictionary alloc]initWithObjects:array forKeys:levels];
NSLog(#"TEST: %#", [dict objectForKey:[levels objectAtIndex:1]]);
return YES;
}
- (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 loadFiles];
// Do any additional setup after loading the view, typically from a nib.
self.navigationItem.leftBarButtonItem = self.editButtonItem;
UIBarButtonItem *addButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:self action:#selector(insertNewObject:)];
self.navigationItem.rightBarButtonItem = addButton;
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (void)insertNewObject:(id)sender {
if (!_objects) {
_objects = [[NSMutableArray alloc] init];
}
[_objects insertObject:[NSDate date] atIndex:0];
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:0 inSection:0];
[self.tableView insertRowsAtIndexPaths:#[indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];
}
#pragma mark - Table View
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
if ([expandedSections containsIndex:section]) {
return [array count] +2;
}
return [array count];
}
// Customize the appearance of table view cells.
- (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;
}
if (!(indexPath.row %3)==0) {
cell.textLabel.text = [dict objectForKey:[levels objectAtIndex:indexPath.row]];
[cell setIndentationLevel:2];
cell.accessoryType = UITableViewCellAccessoryNone;
cell.accessoryView = nil;
} else {
cell.textLabel.text = [dict objectForKey:[levels objectAtIndex:indexPath.row]];
[cell setIndentationLevel:0];
}
return cell;
}
- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath {
// Return NO if you do not want the specified item to be editable.
return YES;
}
- (void)tableView:(UITableView *)tableView commitEditingStyle: (UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
if (editingStyle == UITableViewCellEditingStyleDelete) {
[_objects removeObjectAtIndex:indexPath.row];
[tableView deleteRowsAtIndexPaths:#[indexPath] withRowAnimation:UITableViewRowAnimationFade];
} else if (editingStyle == UITableViewCellEditingStyleInsert) {
// Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view.
}
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
if (!self.detailViewController) {
self.detailViewController = [[DetailViewController alloc] initWithNibName:#"DetailViewController" bundle:nil];
}
BOOL currentlyExpanded = [expandedSections containsIndex:indexPath.row];
//[tableView deselectRowAtIndexPath:indexPath animated:YES];
NSLog(#"CurrentlyExpanded : %d", currentlyExpanded);
NSLog(#"TEST: %#", [dict objectForKey:[levels objectAtIndex:indexPath.row ]]);
if ((indexPath.row %3)==0) {
// only first row toggles exapand/collapse
[tableView deselectRowAtIndexPath:indexPath animated:YES];
NSInteger section = indexPath.section;
BOOL currentlyExpanded = [expandedSections containsIndex:section];
NSInteger rows;
NSMutableArray *tmpArray = [NSMutableArray array];
if (currentlyExpanded) {
rows = 2;
[expandedSections removeIndex:section];
} else {
[expandedSections addIndex:section];
rows = 2;
}
for (int i=indexPath.row+1; i<=(indexPath.row + rows); i++) {
NSIndexPath *tmpIndexPath = [NSIndexPath indexPathForRow:i
inSection:section];
[tmpArray addObject:tmpIndexPath];
}
if (currentlyExpanded) {
[tableView deleteRowsAtIndexPaths:tmpArray
withRowAnimation:UITableViewRowAnimationTop];
} else {
[tableView insertRowsAtIndexPaths:tmpArray
withRowAnimation:UITableViewRowAnimationTop];
}
}
if ((indexPath.row %3)>0) {
NSDate *object = _objects[indexPath.row];
self.detailViewController.detailItem = object;
[self.navigationController pushViewController:self.detailViewController animated:YES];
}
}
#end

Answer 1

Take a look at TLIndexPathTools. It greatly simplifies building dynamic tables like this. It does all the work calculating and performing the batch updates for you. Try running the Outline sample project. It demonstrates how to build an expandable tree without using sections. You can accomplish what you need by just building up a two-level tree.