My requirement is something like that,
On top of NSOutlineview there would be a search textfield and NSOutline view may contains the nested Groups,
if a item / row is matching with the search query, then it should be displayed, which its all parent node till root level,
the way i am doing is as follows,
1 -- Depending upon the what user has entered , re-building tne NSOutlineview datasource ( Nothing but an NSArray )
2 -- Have implemented all delegate method,
Now my problem is Group is not getting expanded automatically, I know i should call
-expandItem:expandChildren:,
but my questions is from where i should call this, i called it after reload data but it didn't work
i tried to call it something like this ,,,,
- (id)outlineView:(NSOutlineView *)outlineView objectValueForTableColumn:(NSTableColumn *)aTableColumn byItem:(id)item {
if(aTableColumn == nil){
[self log:#"aTableColumn is NIL "];
return nil;
}
if([[aTableColumn identifier] isEqualToString:#"firstColumn"] ){
if ( [myOutlineView shouldExpandIt:item]){
[myOutineView expandItem:item];
}
return item;
}
return item;
}
but its faulting perhaps going to recursive loop
Any other way to achieve the same.
Thanks to all of you to look into this,
By putting log, i found out to be , it seems to be [NSOutlineView reloadData ] seems to be blocking call,
so after that if i need to expand / collapse group , i am using
[pCTOutlineView expandItem:pValue];
and working so far....
I am using performBatchUpdates() to update my collection view, where I am doing a complete refresh, i.e. delete whatever was in it and re-insert everything. The batch updates are done as part of an Observer which is attached to a NSMutableArray (bingDataItems).
cellItems is the array containing items that are or will be inserted into the collection view.
Here is the code:
- (void) observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
cultARunner *_cultARunner = [cultARunner getInstance];
if ( [[_cultARunner bingDataItems] count] ) {
[self.collectionView reloadData];
[[self collectionView] performBatchUpdates: ^{
int itemSize = [cellItems count];
NSMutableArray *arrayWithIndexPaths = [NSMutableArray array];
// first delete the old stuff
if (itemSize == 0) {
[arrayWithIndexPaths addObject: [NSIndexPath indexPathForRow: 0 inSection: 0]];
}
else {
for( int i = 0; i < cellItems.count; i++ ) {
[arrayWithIndexPaths addObject:[NSIndexPath indexPathForRow:i inSection:0]];
}
}
[cellItems removeAllObjects];
if(itemSize) {
[self.collectionView deleteItemsAtIndexPaths:arrayWithIndexPaths];
}
// insert the new stuff
arrayWithIndexPaths = [NSMutableArray array];
cellItems = [_cultARunner bingDataItems];
if ([cellItems count] == 0) {
[arrayWithIndexPaths addObject: [NSIndexPath indexPathForRow: 0 inSection: 0]];
}
else {
for( int i = 0; i < [cellItems count]; i++ ) {
[arrayWithIndexPaths addObject:[NSIndexPath indexPathForRow:i inSection:0]];
}
}
[self.collectionView insertItemsAtIndexPaths:arrayWithIndexPaths];
}
completion:nil];
}
}
I get this error, but not all of the times (why ?)
2012-12-16 13:17:59.789 [16807:19703] *** Assertion failure in -[UICollectionViewData indexPathForItemAtGlobalIndex:], /SourceCache/UIKit_Sim/UIKit-2372/UICollectionViewData.m:442
2012-12-16 13:17:59.790 [16807:19703] DEBUG: request for index path for global index 1342177227 when there are only 53 items in the collection view
I checked the only thread that mentioned the same problem here: UICollectionView Assertion failure, but it is not very clear i.e. doing [collectionview reloadData] is not advisable in the performBatchUpdates() block.
Any suggestions on what might be going wrong here ?
Finally! Ok, here's what was causing this crash for me.
As previously noted, I was creating supplementary views in order to provide custom-styled section headers for my collection view.
The problem is this: it appears that the indexPath of a supplementary view MUST correspond to the indexPath of an extant cell in the collection. If the supplementary view's index path has no corresponding ordinary cell, the application will crash. I believe that the collection view attempts to retrieve information for a supplementary view's cell for some reason during the update procedure. It crashes when it cannot find one.
Hopefully this will solve your problem too!
This is the proper workaround to this crash:
Each of your supplementary views are associated with a certain index path. If you don't have a cell at that index path (initial load, you've deleted the row, etc), return a height of 0 for your supplementary view via your layout's delegate.
So, for a flow layout, implement UICollectionViewDelegateFlowLayout's
(CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout referenceSizeForHeaderInSection:(NSInteger)section
method (and the corresponding footer method, if you're using footers) with the following logic
if ( you-have-a-cell-at-the-row-for-this-section )
return myNormalHeaderSize;
else return CGSizeMake( 0,0 );
Hope this helps!
reloadData doesn't work for me, because the whole purpose of using performBatchUpdates is to get the changes animated. If you use reloadData you only refresh the data, but without animations.
So suggestions of "replace performBatchUpdates with reloadData" is pretty much saying "give up on what you're trying to do."
I'm sorry, I'm just frustrated because this error keeps coming up for me while I'm trying to do some great animated updates and my model is 100 % correct, it's some iOS magic inside getting broken and forcing me to change my solutions completely.
My opinion is that Collection Views are still buggy and can't do complicated animated refreshes, even though they should be able to. Because this used to be the same thing for Table Views but those are now pretty stable (it took time, though).
//Edit (Sep 1, 2013)
The reported bug is closed now so this issues seems to have been resolved by Apple already.
I have been having the same problem.
I have tried a number of variations, but the final one that seems to work is [self.collectionView reloadData], where "self.collectionView"is the name of your collection view.
I have tried the following methods, straight from the "UICollectionView Class Reference": inserting, moving, and deleting items.
These were used at first, to "move" the item from one section to another.
deleteItemsAtIndexPaths:
insertItemsAtIndexPaths:
Next, I tried moveItemAtIndexPath:toIndexPath:.
They all produced the following error:
Assertion failure in -[UICollectionViewData indexPathForItemAtGlobalIndex:], /SourceCache/UIKit_Sim/UIKit-2372/UICollectionViewData.m:442
So, try the "reloadData" method.
If you remove the last cell from a section containing header/footer the bug appears.
I tried to return nil for header/footer size/element at that time and this sometimes fixes the issue.
Options:
Reload the whole table view instead of animating the removal of the last item.
Add an additional invisible, basic cell with a size less than 1.
A cheeseball mistake that can lead to this error is reusing the same UICollectionViewFlowLayout on multiple collectionViews on the same viewcontroller! Just init different flowLayouts for each collectionview and you'll be good to go!
I ran into this problem when I delete one of the cells from my collection view.
The problem was that I use a custom layout, and the call layoutAttributesForElementsInRect was returning more than the number of cells in the collection view after the delete.
Apparently UICollectionView just iterates through the array returned by the method without checking the number of cells.
Modifying the method to return the same number of layout attributes solved the crash.
I still couldn't figure out how the global index was incremented so much, but I solved my problem by inserting a temporary item in the underlying datasource array i.e. cellItems and calling [self.collectionview reloadData] in viewDidLoad().
This inserts a placeholder cell temporarily in the collection view until I trigger the actual process using performBatchUpdates().
I'm running into index beyond bounds exception in one of my UITableViews and I think it could be down to some multithreading issues. Here's what I believe is happening:
I have a UITableView and it's data source is a regular NSMutableArray.
This NSMutableArray which is backing my UITableView is updated every couple of seconds with the contents of an API response.
After each update, UITableView's reloadData is being invoked to ensure that the user sees new data from the API server.
Sometimes a index beyonds bounds exception gets thrown.
Here's my code:
-(NSMutableArray*) currentBetEvents
{
return currentMarketId == nil ? [[BFOpenBetsModel sharedInstance] betEvents] : filteredBetEvents;
}
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
NSArray *betEvents = [self currentBetEvents];
return [betEvents count];
}
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSArray *betEvents = [self currentBetEvents];
id obj = [betEvents objectAtIndex:indexPath.section] // this is where it blows up
Basically, I get an exception while trying to access an object in the betEvents structure at index 0.
What I believe is happening is:
reloadData is called on the UITableView
numberOfSectionsInTableView: is invoked which returns a value > 0.
a rouge thread arrives and clears out the UITableView's data source.
cellForRowAtIndexPath: is invoked and it bombs.
Is there any way to ensure that this doesn't happen? Do I need to start using some primitive locks on the data source to ensure that it doesn't get updated while the table is being updated?
EDIT
Took another look at how the data structures returned by currentBetEvents can be altered and it looks like the filteredBets & betEvents can be cleared out as a result of the following code:
[[NSNotificationCenter defaultCenter] postNotificationName:kUserLoggedOutNotification object:nil];
This notification is posted whenever the user logs out. Whenever a user logs out of the app, I need to clear out the filteredBets and betEvents arrays. Is it possible that the following could happen:
reloadData is called on the UITableView
numberOfSectionsInTableView: is invoked which returns a value > 0.
User logs out which kicks off the notification & clears out the data structures.
cellForRowAtIndexPath: is invoked and it bombs.
Thanks,
Sean
Definitely sounds like a threading problem. You might try something like this:
// view controller
#synchronized([[BFOpenBetsModel sharedInstance] betEvents])
{
[self.tableView reloadData];
}
…
// data model
#synchronized(_betEvents) // or whatever the instance variable -betEvents returns is
{
[_betEvents addObject:whatever];
}
I am currently going through the 3rd Edition of the Mac OSX Cocoa book from the Big Nerd Ranch guys and I am editing my program to include table views. Here the code from the AppController.m file where I have to implement the required protocol methods from the TableView:
-(id)init{
self = [super init];
voiceArray = [NSSpeechSynthesizer availableVoices];
speechSynth = [[NSSpeechSynthesizer alloc] initWithVoice:nil];
[speechSynth setDelegate:self];
return self;
}
-(int)numberOfRowsInTableView:(NSTableView *)tv{
NSLog(#"Getting number of rows in table view: %lu", [voiceArray count]);
return [voiceArray count];
}
-(id)tableView:(NSTableView *)tv objectValueForTableColumn:(NSTableColumn *)tableColumn row:(NSInteger)row{
NSString *v = [voiceArray objectAtIndex:row];
NSDictionary *dict = [NSSpeechSynthesizer attributesForVoice:v];
NSLog(#"Voice Name %#", [dict objectForKey:NSVoiceName]);
return [dict objectForKey:NSVoiceName];
}
-(void)tableViewSelectionDidChange:(NSNotification *)notification{
int row = [tableView selectedRow];
NSLog(#"row selected %d", row);
if(row == 1){
return;
}
NSString *selectedVoice = [voiceArray objectAtIndex:row];
[speechSynth setVoice:selectedVoice];
NSLog(#"new voice %# ", selectedVoice);
}
When the app first loads I get the following output:
2012-05-27 15:02:29.040 Speakline[42836:f03] Getting number of rows in
table view: 24 2012-05-27 15:02:29.042 Speakline[42836:f03] row
selected 2 2012-05-27 15:02:29.043 Speakline[42836:f03] new voice
com.apple.speech.synthesis.voice.Alex 2012-05-27 15:02:29.162
Speakline[42836:f03] Voice Name Agnes 2012-05-27 15:02:29.163
Speakline[42836:f03] Voice Name Albert
I want to make sure I understand fully what is going on here. In order to do this I have a couple of questions.
It looks like the numberOfRowsInTableView: method was automatically called after the init method. Is this correct?
How often does objectValueForTableColumn: get called? What events prompt that method to get called? Also, in the code there, the return statement confused me. Where exactly does this return value go?
As a side note they wanted me to connect the Outlets and the AppController via control+clicking (via the connections panel) and linking them in that way. What alternatives are there avaialble for connecting delegates and datasources to different kinds of views without doing this? I am assuming that adding NSTableViewDelegate in the controller header file might be one way. If you have the option of control+click connecting all your views to outlets and so on vs programmatically setting it all up is it just a matter of preference at this point? It just seems to me that in order to understand what is going on it might be better to just write the code yourself.
1) Both numberOfRowsInTableView and objectValueForTableColumn:Row: get called soon after the nib is unarchived (I'm not sure of the exact order of things), so the table view can be populated with data.
2) The loading of the table and reloading or adding new data as well as scrolling will cause objectValueForTableColumn:row: to be called (by the table view). It gets called for each row that is populated. The value goes to the table view, that's how it gets its data.
3) The other way to connect delegates is to do it in code with setDelegate:, but putting NSTableViewDelegate in the .h file does not do that -- that's just a promise to the compiler that you will implement some or all of the delegate messages.
I am just learning how to setup a multiple picker and I am a little curious about the two labeled sections below:
// METHOD_001
NSInteger row_001 = [doublePicker selectedRowInComponent:0];
NSInteger row_002 = [doublePicker selectedRowInComponent:1];
NSString *selected_001 = [pickerData_001 objectAtIndex:row_001];
NSString *selected_002 = [pickerData_002 objectAtIndex:row_002];
EDIT_001:
Maybe if I simplify this a little .... I know what METHOD_001 is doing, but what about the method below. If I comment it out my code still runs but the picker UI does not get populated with my data, so its obviously involved in taking data from the dataSource so the picker can display it. One puzzling aspect is that it uses "objectAtIndex:row" to access an item, even though the whole UI needs populating (i.e. all the rows) Does this then mean that this gets called for each row, seems funny that it does not take a NSArray nd populated the picker UI in one shot?
// DELEGATE
-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {
if(component == kCoffeeIndex) return [pickerData_001 objectAtIndex:row];
return [pickerData_002 objectAtIndex:row];
}
gary
The delegate method -pickerView:titleForRow:forComponent: will be called every time the UI thinks the data is needed.
It doesn't take an array because the titles may be generated dynamically or retrieved lazily. It's actually the same story for table views. Usually only the visible rows will be loaded, to reduce the data required.