uncaught exception 'NSRangeException', reason: '*** -[__NSArrayI objectAtIndex - ios

Question

Im new to objective C and I was wondering if someone can help me figure out why my app keeps crashing. I believe it has something to do with my Array but I'm not sure how to fix it.. Can someone help please???..
Here's the Log output when it crashes:
2014-11-26 10:37:42.172 SamplePhotoReDo[89697:109203550] *** Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[__NSArrayI objectAtIndex:]: index 2 beyond bounds [0 .. 0]'
*** First throw call stack:
(
0 CoreFoundation 0x000000010c75af35 __exceptionPreprocess + 165
1 libobjc.A.dylib 0x000000010c09cbb7 objc_exception_throw + 45
2 CoreFoundation 0x000000010c65301e -[__NSArrayI objectAtIndex:] + 190
3 UIKit 0x000000010d67474a -[UITableViewDataSource tableView:heightForHeaderInSection:] + 39
4 UIKit 0x000000010d221f4e -[UITableView _delegateWantsHeaderForSection:] + 261
5 UIKit 0x000000010d3a6983 -[UISectionRowData refreshWithSection:tableView:tableViewRowData:] + 162
6 UIKit 0x000000010d3ace45 -[UITableViewRowData rectForFooterInSection:heightCanBeGuessed:] + 320
7 UIKit 0x000000010d3acf3a -[UITableViewRowData heightForTable] + 56
8 UIKit 0x000000010d1ffaf0 -[UITableView _updateContentSize] + 381
9 UIKit 0x000000010d21cecd -[UITableView didMoveToWindow] + 65
10 UIKit 0x000000010d1a39a0 -[UIView(Internal) _didMoveFromWindow:toWindow:] + 1482
11 UIKit 0x000000010d1b4333 -[UIScrollView _didMoveFromWindow:toWindow:] + 55
12 UIKit 0x000000010d1a368e -[UIView(Internal) _didMoveFromWindow:toWindow:] + 696
13 UIKit 0x000000010d19c112 __45-[UIView(Hierarchy) _postMovedFromSuperview:]_block_invoke + 125
14 UIKit 0x000000010d19c086 -[UIView(Hierarchy) _postMovedFromSuperview:] + 437
15 UIKit 0x000000010d1a5f4b -[UIView(Internal) _addSubview:positioned:relativeTo:] + 1604
16 UIKit 0x000000010d486534 -[UINavigationTransitionView transition:fromView:toView:] + 479
17 UIKit 0x000000010d2841ef -[UINavigationController _startTransition:fromViewController:toViewController:] + 2967
18 UIKit 0x000000010d284487 -[UINavigationController _startDeferredTransitionIfNeeded:] + 523
19 UIKit 0x000000010d284f47 -[UINavigationController __viewWillLayoutSubviews] + 43
20 UIKit 0x000000010d3ca509 -[UILayoutContainerView layoutSubviews] + 202
21 UIKit 0x000000010d1a8973 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 521
22 QuartzCore 0x000000011052bde8 -[CALayer layoutSublayers] + 150
23 QuartzCore 0x0000000110520a0e _ZN2CA5Layer16layout_if_neededEPNS_11TransactionE + 380
24 QuartzCore 0x000000011052087e _ZN2CA5Layer28layout_and_display_if_neededEPNS_11TransactionE + 24
25 QuartzCore 0x000000011048e63e _ZN2CA7Context18commit_transactionEPNS_11TransactionE + 242
26 QuartzCore 0x000000011048f74a _ZN2CA11Transaction6commitEv + 390
27 UIKit 0x000000010d12d54d -[UIApplication _reportMainSceneUpdateFinished:] + 44
28 UIKit 0x000000010d12e238 -[UIApplication _runWithMainScene:transitionContext:completion:] + 2642
29 UIKit 0x000000010d12cbf2 -[UIApplication workspaceDidEndTransaction:] + 179
30 FrontBoardServices 0x0000000112f002a3 __31-[FBSSerialQueue performAsync:]_block_invoke + 16
31 CoreFoundation 0x000000010c69053c __CFRUNLOOP_IS_CALLING_OUT_TO_A_BLOCK__ + 12
32 CoreFoundation 0x000000010c686285 __CFRunLoopDoBlocks + 341
33 CoreFoundation 0x000000010c686045 __CFRunLoopRun + 2389
34 CoreFoundation 0x000000010c685486 CFRunLoopRunSpecific + 470
35 UIKit 0x000000010d12c669 -[UIApplication _run] + 413
36 UIKit 0x000000010d12f420 UIApplicationMain + 1282
37 SamplePhotoReDo 0x000000010bb60453 main + 115
38 libdyld.dylib 0x000000010f2d2145 start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb)'
Here's the code that might be causing the crash:
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 1 + self.collectionsFetchResults.count;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
NSInteger numberOfRows = 0;
if (section == 0) {
numberOfRows = 1; // "All Photos" section
} else {
PHFetchResult *fetchResult = self.collectionsFetchResults[section - 1];
numberOfRows = fetchResult.count;
}
return numberOfRows;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = nil;
NSString *localizedTitle = nil;
if (indexPath.section == 0) {
cell = [tableView dequeueReusableCellWithIdentifier:AllPhotosReuseIdentifier forIndexPath:indexPath];
localizedTitle = NSLocalizedString(#"All Photos", #"");
} else {
cell = [tableView dequeueReusableCellWithIdentifier:CollectionCellReuseIdentifier forIndexPath:indexPath];
PHFetchResult *fetchResult = self.collectionsFetchResults[indexPath.section - 1];
PHCollection *collection = fetchResult[indexPath.row];
localizedTitle = collection.localizedTitle;
}
cell.textLabel.text = localizedTitle;
return cell;
}
- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section
{
NSString *title = nil;
if (section > 0) {
title = self.collectionsLocalizedTitles[section - 1];
}
return title;
}
#pragma mark - PHPhotoLibraryChangeObserver
- (void)photoLibraryDidChange:(PHChange *)changeInstance
{
// Call might come on any background queue. Re-dispatch to the main queue to handle it.
dispatch_async(dispatch_get_main_queue(), ^{
NSMutableArray *updatedCollectionsFetchResults = nil;
for (PHFetchResult *collectionsFetchResult in self.collectionsFetchResults) {
PHFetchResultChangeDetails *changeDetails = [changeInstance changeDetailsForFetchResult:collectionsFetchResult];
if (changeDetails) {
if (!updatedCollectionsFetchResults) {
updatedCollectionsFetchResults = [self.collectionsFetchResults mutableCopy];
}
[updatedCollectionsFetchResults replaceObjectAtIndex:[self.collectionsFetchResults indexOfObject:collectionsFetchResult] withObject:[changeDetails fetchResultAfterChanges]];
}
}
if (updatedCollectionsFetchResults) {
self.collectionsFetchResults = updatedCollectionsFetchResults;
[self.tableView reloadData];
}
});
}

Answer 1

reason: '*** -[__NSArrayI objectAtIndex:]: index 2 beyond bounds [0 .. 0]'
Quite clear, your array doesn't have as many elements as you think it has. Put a break point at the places where your array is populated and double check it's as expected.