I have an NSArray of custom NSObjects. Each object has some properties and an image that I would like to display in a grid view. NSMatrix appears to be a good solution to my problem, but I am having issues getting the content of the objects to display.
Couple of things to note.
I am not using core data
I am trying to do this programmatically
I have considered using NSCollectionView but NSMatrix appears to be a better solution in this case
All the cells follow the same display format as each other - i.e. I'm not wanting to pass different cells different types of objects, just a different instance of the object
Assume I have an NSView (matrixContainerView) in a window. The controller file has an IBOutlet to matrixContainerView. In my controller I have the following in my awakeFromNib:
NSMatrix* matrix = [[NSMatrix alloc]
initWithFrame:[matrixContainerView bounds]
mode:NSRadioModeMatrix
cellClass:[MyCustomCell class]
numberOfRows:5
numberOfColumns:5];
[matrix setCellSize:NSMakeSize(116, 96)];
[matrix setNeedsDisplay:YES];
[matrixContainerView addSubview:[matrix autorelease]];
[matrixContainerView setNeedsDisplay:YES];
The class MyCustomCell header looks like the following:
#interface MyCustomCell : NSCell {
MyModel * theObject;
}
-(MyModel *)theObject;
-(void)setTheObject:(MyModel *)newValue;
And the implementation file as follows (drawing simplified):
#implementation MyCustomCell
-(void)drawInteriorWithFrame:(NSRect)theFrame inView:(NSView *)theView {
...drawing code using MyModel e.g. [MyModel isValid] etc...
}
-(MyModel *)theObject {
return theObject;
}
-(void)setTheObject:(MyModel *)newValue {
[theObject autorelease];
theObject = [newValue retain];
}
#end
After some initialization and population of the array containing MyModel objects in the controller, I want to populate the NSMatrix with instances of the objects.
How do I do this?
I have tried adding just two objects from the array as follows (just as a test):
MyCustomCell * cellOne = (MyCustomCell *)[matrix cellAtRow:0 column:0];
[cell setTheObject:[myArrayOfObjects objectAtIndex:0]];
MyCustomCell * cellTwo = (MyCustomCell *)[matrix cellAtRow:0 column:1];
[cellTwo setTheObject:[myArrayOfObjects objectAtIndex:1]];
But this just creates the first object image. If the above had worked, it would been a straightforward task of enumerating through the array and adding the objects.
How do I go about adding the cells and passing the appropriate objects to those cells in order that they can be displayed correctly?
The Apple docs are sparse to say the least on NSMatrix as far as the programming guide goes. The information in there is very useful to me, but only after I have added the objects and got them displaying!
Update
If I do not add the two objects (as per my example above) the output is no different, i.e. a single representation of my custom cell is drawn to screen. This tells me that the single representation I see is being done at the initialization of the matrix and in fact I wasn't drawing anything to column 0 row 0 when in fact I thought I was. Which leaves me now more confused.
Might be that the matrix actually has the two cells but its frame is too small to display them?
After adding the cells try calling [matrix sizeToCells]
Related
I'm populating a NSOUtlineView with a NSTreeController.
The NSTreeController is a 3 levels hierarchy controller (CBMovie, CBDisc and CBEpisode), but only the first 2 levels are displayed in the outline view.
The implementation is the same for all objects: I've implemented methods to specify children, children count and if the object is a leaf. These methods are correctly called for all objects (also for those ones that are not displayed, the grandchildren: CBEpisode).
In the outline View, everything is displayed correctly for the first 2 level. But grandchildren are never displayed, I don't have the option to expand their parent to see them. I can only see CBMovie and CBDiscs.
I'm wondering if there is another setting I'm missing, about how deep the nodes can expand in NSTreeControllers or NSOutlineView configurations.
Below: Implementation in one of the three nodes.
Each node class has different path to its children. This is specified in the -(NSArray*)children method (correctly called).
-(NSArray*)children
{
return [[self Episodes] allObjects];
}
-(int)childrenCount
{
return [[self Episodes] count];
}
-(BOOL)isLeaf
{
return ![[self Episodes] count];
}
Output of logging code. The datasource, the NSTreeController, seems to have the correct structure.
CBMovie
CBDisc
CBEpisode
CBEpisode
CBMovie
CBDisc
CBDisc
CBDisc
CBDisc
CBMovie
CBDisc
CBEpisode
CBEpisode
This is how I populate the NSOutlineView (cell based). I don't use datasource methods, but I'm binding it programmatically.
NSMutableDictionary *bindingOptions = [[NSMutableDictionary alloc] initWithCapacity:2];
if (metadata.valueTransformer) {
[bindingOptions setObject:metadata.valueTransformer forKey:NSValueTransformerNameBindingOption];
}
[bindingOptions setObject:[NSNumber numberWithBool:NO] forKey:NSCreatesSortDescriptorBindingOption];
[bindingOptions setObject:[NSNumber numberWithBool:NO] forKey:NSRaisesForNotApplicableKeysBindingOption];
[newColumn bind:#"value" toObject:currentItemsArrayController withKeyPath:[NSString stringWithFormat:#"arrangedObjects.%#", metadata.columnBindingKeyPath] options:bindingOptions];
Examining the NSTreeController side
The NSTreeController is a 3 levels hierarchy controller, but only the first 2 levels are displayed in the outline view.
Have you confirmed that all three levels are loaded into your NSTreeController? You could do this by logging its contents to the console with the extension below. If the output produced by this code matches what appears in your outline-view, the problem is probably on the NSTreeController side, not the outline-view.
#import "NSTreeController+Logging.h"
#implementation NSTreeController (Logging)
// Make sure this is declared in the associated header file.
-(void)logWithBlock:(NSString * (^)(NSTreeNode *))block {
NSArray *topNodes = [self.arrangedObjects childNodes];
[self logNodes:topNodes withIndent:#"" usingBlock:block];
}
// For internal use only.
-(void)logNodes:(NSArray *)nodes
withIndent:(NSString *)indent
usingBlock:(NSString * (^)(NSTreeNode *))block {
for (NSTreeNode * each in nodes) {
NSLog(#"%#%#", indent, block(each));
NSString *newIndent = [NSString stringWithFormat:#" %#", indent];
[self logNodes:each.childNodes withIndent:newIndent usingBlock:block];
}
}
#end
The above code does not need to be adjusted, all you need to do is call it with a customised block:
-(void)logIt {
[self.treeController logWithBlock:^NSString *(NSTreeNode * node) {
// This will be called for every node in the tree. This implementation
// will see the object's description logged to the console - you may
// want to do something more elaborate.
NSString *description = [[node representedObject] description];
return description;
}];
}
Examining the NSOutlineView side
If all the data seems to have loaded correctly into the NSTreeController you could have a look at how your NSOutlineView is populated. The delegate method -[NSOutlineViewDelegate outlineView:viewForTableColumn:item] is a good place to start. The item argument is the NSTreeNode instance, so, before you return the relevant view you can look at this node and make sure it's behaving as expected. In your case, you should scrutinize the properties of item objects that are representing CBDisc objects. (You may need to click on disclosure buttons to get this method to fire for the relevant objects.)
-(NSView *)outlineView:(NSOutlineView *)outlineView
viewForTableColumn:(NSTableColumn *)tableColumn
item:(id)item {
NSTreeNode *node = (NSTreeNode *)item;
NSManagedObject *representedObject = (NSManagedObject *)node.representedObject;
// Query the node
NSLog(#"%# <%#>", representedObject.description, [representedObject class]);
NSLog(#" node is a leafNode: %#", node.isLeaf ? #"YES" : #"NO");
NSLog(#" node has child-count of: %lu", (unsigned long)node.childNodes.count);
// Query the NSManagedObject
// your stuff here...
// This is app-specific - you'll probably need to change the identifier.
return [outlineView makeViewWithIdentifier:#"StandardTableCellView" owner:self];
}
So, I've figured out why.
Quite stupid: the main outline column containing the disclosure arrows was 20px width only and the arrows of the children had indentation.
I'm using the outline column for the arrows only and not the titles of the nodes, that's why it's so narrow.
I had disabled indentation and now I can see all arrows.
I have a UITableView with a property(strong, nonatomic)NSMutableArray *currentContent, I also have a property(strong, nonatomic)NSMutableArray *cellHeights to keep track of the cell heights cos the user could expand or collapse each cell. The self.currentContent is set by another controller which load data from a web service, so it will change as the data load, I want to keep both of these variables in sync. As soon as currentContent is updated, I want to update cellHeights. How do I do that?
I tried:
- (void)setCurrentContent:(NSMutableArray *)currentContent{
_currentContent = currentContent;
self.cellHeights = [NSMutableArray arrayWithDefaultHeightsForCellCount:[currentContent count]];
}
But it's not working, cos it will only be set at the first time when I set currentContent, when it's empty. So self.cellHeights currently will stay empty. When there is finally value in self.currentContent, self.cellHeights was not updated.
I've done a similar thing before, with variable cell heights depending on the content from your web-service, and I'd advise that keeping an array of cell heights might not be the best idea.
What I did was to create a 'fake' cell in the viewDidLoad: method, that I use just to calculate cell heights.
Then I use the 'heightForRowAtIndexPath' method to specify how tall cell should be by populating the 'fake' cell with the data for the index path, then finding out how tall that cell is. For example:
#interface MyTableViewController()
#property (nonatomic, strong ) MyCustomTableViewCell *cellForTestingHeight;
#end
#implementation MyTableViewController
- (void)viewDidLoad {
[super viewDidLoad]
self.cellForTestingHeight = [[MyCustomTableViewCell alloc] initWithStyle:UITableViewCellStyleDefault];
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
NSDictionary *myData = [self.data objectAtIndex:indexPath.row];
self.cellForTestingHeight.viewData = myData;
return self.cellForTestingHeight.height;
}
#end
This code assumes that you've created a class called MyCustomTableViewCell which has a method to set the viewData property on it, and that after setting that property you'll be able to tell how tall that cell will be by accessing a height property.
What you need to do is observe changes to the mutable array itself, not your property which references the array. This should be straightforward but unfortunately there is a twist...
OK, let's assume there is no twist and rather than an NSMutableArray your property is of type MyObservableClass. Then to setup the observing you would do something like this (all code is pseudo - i.e. typed into the answer):
- (void)setCurrentContent:(MyObservableClass *)currentContent
{
if(_currentContent)
[_currentContent removeObserver:self forKeyPath:#"myObservableProperty"];
_currentContent = currentContent;
[_currentContent addObserver:self forKeyPath:#"myObservableProperty" ...];
}
Now whenever the currentContent is changed your code stops observing the properties of its old value and starts observing properties of its new value.
Easy, but its not quite that simple for arrays...
The twist, though KVO will inform an observer of additions, deletions and changes to a collection the NSMutableArray class doesn't issue those notifications. You need to use a proxy for the array, and such a proxy is provided by the frameworks - see for example NSArrayController and mutableArrayValueForKey:. However the second part of the twist is that the changes to the array must be done through this proxy - you can't have your client call setCurrentContent and pass any NSMutableArray if you are going to observe it, your client needs to pass in the proxy... Whether you can use this easily in your design you'll have to figure out. You'll need to read Automatic Change Notification in this document and other Apple docs to sort this out.
This sounds more complicated that it needs to be, maybe somebody else will provide a more succinct way of doing this.
I am trying to nest NSCollection view inside of one another. I have tried to create a new project using the Apple Quick Start Guide as a base.
I start by inserting a collection view into my nib, to the view that is automatically added I drag another collection view onto it. The sub-collection view added gets some labels. Here is a picture of my nib:
I then go back and build my models:
My second level model .h is
#interface BPG_PersonModel : NSObject
#property(retain, readwrite) NSString * name;
#property(retain, readwrite) NSString * occupation;
#end
My First level model .h is:
#interface BPG_MultiPersonModel : NSObject
#property(retain, readwrite) NSString * groupName;
#property(retain,readwrite) NSMutableArray *personModelArray;
-(NSMutableArray*)setupMultiPersonArray;
#end
I then write out the implementation to make some fake people within the first level controller(building up the second level model):
(edit) remove the awakefromnibcode
/*- (void)awakeFromNib {
BPG_PersonModel * pm1 = [[BPG_PersonModel alloc] init];
pm1.name = #"John Appleseed";
pm1.occupation = #"Doctor";
//similar code here for pm2,pm3
NSMutableArray * tempArray = [NSMutableArray arrayWithObjects:pm1, pm2, pm3, nil];
[self setPersonModelArray:tempArray];
} */
-(NSMutableArray*)setupMultiPersonArray{
BPG_PersonModel * pm1 = [[BPG_PersonModel alloc] init];
pm1.name = #"John Appleseed";
pm1.occupation = #"Doctor";
//similar code here for pm2,pm3
NSMutableArray * tempArray = [NSMutableArray arrayWithObjects:pm1, pm2, pm3, nil];
return tempArray;
}
Finally I do a similar implementation in my appdelegate to build the multiperson array
- (void)awakeFromNib {
self.multiPersonArray = [[NSMutableArray alloc] initWithCapacity:1];
BPG_MultiPersonModel * mpm1 = [[BPG_MultiPersonModel alloc] init];
mpm1.groupName = #"1st list";
mpm1.personModelArray = [mpm1 setupMultiPersonArray];
(I'm not including all the code here, let me know if it would be useful.)
I then bind everything as recommended by the quick start guide. I add two nsarraycontrollers with attributes added to bind each level of array controller to the controller object
I then bind collectionview to the array controller using content bound to arrangedobjects
Finally I bind the subviews:
with the grouptitle label to representedobject.grouptitle object in my model
then my name and occupation labels to their respective representedobjects
I made all the objects kvo compliant by including the necessary accessor methods
I then try to run this app and the first error I get is: NSCollectionView item prototype must not be nil.
(edit) after removing awakefromnib from the first level model I get this
Has anyone been successful at nesting nscollection views? What am I doing wrong here? Here is the complete project zipped up for others to test:
http://db.tt/WPMFuKsk
thanks for the help
EDITED:
I finally contacted apple technical support to see if they could help me out.
Response from them is:
Cocoa bindings will only go so far, until you need some extra code to make it all work.
When using arrays within arrays to populate your collection view the
bindings will not be transferred correctly to each replicated view
without subclassing NSCollectionView and overriding
newItemForRepresentedObject and instantiating the same xib yourself,
instead of using the view replication implementation provided by
NSCollectionView.
So in using the newItemForRepresentedObject approach, you need to
factor our your NSCollectionViewItems into separate xibs so that you
can pass down the subarray of people from the group collection view to
your inner collection view.
So for your grouped collection view your override looks like this:
- (NSCollectionViewItem *)newItemForRepresentedObject:(id)object
{
BPG_MultiPersonModel *model = object;
MyItemViewController *item = [[MyItemViewController alloc] initWithNibName:#"GroupPrototype" bundle:nil];
item.representedObject = object;
item.personModelArray = [[NSArrayController alloc] initWithContent:model.personModelArray];
return item;
}
And for your inner collection subclass your override looks like this:
- (NSCollectionViewItem *)newItemForRepresentedObject:(id)object
{
PersonViewController *item = [[PersonViewController alloc] initWithNibName:#"PersonPrototype" bundle:nil];
item.representedObject = object;
return item;
}
here is a sample project that they sent back to me -
http://db.tt/WPMFuKsk
I am still unable to get this to work with my own project. Can the project they sent back be simplified further?
Please take a closer look at this answer
Short answer:
Extracting each NSView into its own .xib should solves this issue.
Extended:
The IBOutlet’s specified in your NSCollectionViewItem subclass are not connected when the prototype is copied. So how do we connect the IBOutlet’s specified in our NSCollectionViewItem subclass to the controls in the view?
Interface Builder puts the custom NSView in the same nib as the NSCollectionView and NSCollectionViewItem. This is dumb. The solution is to move the NSView to its own nib and get the controller to load the view programmatically:
Move the NSView into its own nib (thus breaking the connection between the NSCollectionViewItem and NSView).
In I.B., change the Class Identity of File Owner to the NSCollectionViewItem subclass.
Connect the controls to the File Owner outlets.
Finally get the NSCollectionViewItem subclass to load the nib:
Usefull links:
how to create nscollectionview programatically from scratch
nscollectionview tips
attempt to nest an nscollectionview fails
nscollectionview redux
I am having trouble using the new Lion functionality to rearrange rows in my app. I am using outlineView:pasteboardWriterForItem: to store the row indexes so that I can access them later when I validate/accept the drop. I create a new NSPasteboardItem to return, and am attempting to store the row number as so:
[pbItem setData: [NSKeyedArchiver archivedDataWithRootObject: [NSNumber numberWithInteger: [fTableView rowForItem: item]]]
forType: TABLE_VIEW_DATA_TYPE];
TABLE_VIEW_DATA_TYPE is a custom string I'm using to distinguish my custom data in the dragging pasteboard. I don't use it outside of dragging these rows.
When attempting the drag, I receive in Console: 'TableViewDataType' is not a valid UTI string. Cannot set data for an invalid UTI.
Of course I could use some of the built-in UTIs for pasteboards, but none of them apply (and using them causes the drag to accept drags other than the rows, which it shouldn't). Is there something I'm missing, like a way to define a custom UTI just for dragging (without making it a "real" UTI since I have no use for it outside of the internal dragging, so it shouldn't be public).
Thanks for any help!
I had similar requirements except I had a grid of objects that I wanted to rearrange by dragging selected objects to a new location. There are several ways of doing this, including creating a custom object and implementing the NSPasteboardWriting and NSPasteboardReading protocols, (and NSCoding protocols if you will be reading data as NSPasteboardReadingAsKeyedArchive), but this seems to be overkill for dragging of objects that remain internal to the application.
What I did involves using the NSPasteboardItem as a wrapper with a custom UTI type (it already implements the NSPasteboardWriting and NSPasteboardReading protocols). First declare a custom UTI type:
#define kUTIMyCustomType #“com.mycompany.MyApp.MyCustomType”
This needs to be defined in the ‘com.domain.MyApp’ format otherwise you will get errors of the form: “XXX is not a valid UTI string. Cannot set data for an invalid UTI.” Apple mentions this in their documentation.
Then you must register this custom UTI type in the view in which your dragging will occur. This can be done at runtime, and does not require any .plist additions. In your view's init method add the following:
[self registerForDraggedTypes:[NSArray arrayWithObjects:(NSString *)kUTIMyCustomType, nil]];
Now, make sure that the delegate is set for this view, and the delegate object implements the required NSDraggingSource and NSDraggingDestination protocol methods. This will allow you to avoid breaking the MVC design pattern, by allowing the designated controller object to handle placing the data on the pasteboard which will likely involve querying model data (i.e., indexes).
Specifically, for placing on the dragging pasteboard the indexes of objects to be moved when dragging begins as NSPasteboardItem wrappers of your index data:
- (void) draggingSession:(NSDraggingSession *)session willBeginAtPoint:(NSPoint)screenPoint
{
NSPasteboard * pboard = [NSPasteboard pasteboardWithName:NSDragPboard];
[pboard clearContents];
NSMutableArray * selectedIndexes = [NSMutableArray array];
// Add NSString indexes for dragged items to pasteboard in NSPasteboardItem wrappers.
for (MyModel * myModel in [self selectedObjects])
{
NSPasteboardItem * pasteboardItem = [[[NSPasteboardItem alloc] init] autorelease];
[pasteboardItem setString:[NSString stringWithFormat:#"%#", [myModel index]]
forType:kUTIMyCustomType];
[selectedIndexes addObject:pasteboardItem];
}
[pboard writeObjects:selectedIndexes];
}
And when the dragging operation completes, to read the dragged index NSPasteboardItem data:
- (BOOL) performDragOperation:(id <NSDraggingInfo>)sender
{
NSPasteboard * pasteboard = [sender draggingPasteboard];
// Check for custom NSPasteboardItem's which wrap our custom object indexes.
NSArray * classArray = [NSArray arrayWithObject:[NSPasteboardItem class]];
NSArray * items = [pasteboard readObjectsForClasses:classArray options:[NSDictionary dictionary]];
if (items == nil)
return NO;
// Convert array of NSPasteboardItem's with NSString index reps. to array of NSNumber indexes.
NSMutableArray * indexes = [NSMutableArray array];
for (NSPasteboardItem * item in items)
[indexes addObject:[NSNumber numberWithInteger:[[item stringForType:kUTIMyCustomType] integerValue]]];
//
// Handle dragged indexes…
//
return YES;
}
Another technique you can use is to just store the indices of the objects you're dragging in an instance variable on the side. Putting everything on the pasteboard isn't strictly necessary unless you're accepting items from another app or vice versa.
In awakeFromNib, register for the NSStringPboardType.
In …pasteboardWriterForRow, return [NSString string].
In …draggingSession:willBegin…, set your instance variable to the indices you want to track.
In validateDrop, return NSDragOperationNone if your instance variable is nil or the view is not yours.
In …draggingSession:ended…, nil out your instance variable.
Hope that helps… I'm using the technique for a table view, but it should be virtually identical for an outline view.
Instead of using a vanilla NSPasteboardItem, you should create a custom object that conforms to the NSPasteboardWriting protocol.
In your custom object, you can implement writableTypesForPasteboard: to return a list of custom UTIs that your pasteboard item supports. You then implement pasteboardPropertyListForType: to return a plist representation of your object for the appropriate custom UTI when the pasteboard asks for it.
You can create a plist from arbitrary data using the +propertyListWithData:options:format:error: method of NSPropertyListSerialization.
You would then override tableView:pasteboardWriterForRow: in your table view data source to return an instance of your custom object.
I am struggling trying to perform what I would think would be a relatively common task. I have an NSTableView that is bound to it's array via an NSArrayController. The array controller has it's content set to an NSMutableArray that contains one or more NSObject instances of a model class. What I don't know how to do is expose the model inside the NSCell subclass in a way that is bindings friendly.
For the purpose of illustration, we'll say that the object model is a person consisting of a first name, last name, age and gender. Thus the model would appear something like this:
#interface PersonModel : NSObject {
NSString * firstName;
NSString * lastName;
NSString * gender;
int * age;
}
Obviously the appropriate setters, getters init etc for the class.
In my controller class I define an NSTableView, NSMutableArray and an NSArrayController:
#interface ControllerClass : NSObject {
IBOutlet NSTableView * myTableView;
NSMutableArray * myPersonArray;
IBOutlet NSArrayController * myPersonArrayController;
}
Using Interface Builder I can easily bind the model to the appropriate columns:
myPersonArray --> myPersonArrayController --> table column binding
This works fine. So I remove the extra columns, leaving one column hidden that is bound to the NSArrayController (this creates and keeps the association between each row and the NSArrayController) so that I am down to one visible column in my NSTableView and one hidden column. I create an NSCell subclass and put the appropriate drawing method to create the cell. In my awakeFromNib I establish the custom NSCell subclass:
MyCustomCell * aCustomCell = [[[MyCustomCell alloc] init] autorelease];
[[myTableView tableColumnWithIdentifier:#"customCellColumn"]
setDataCell:aCustomCell];
This, too, works fine from a drawing perspective. I get my custom cell showing up in the column and it repeats for every managed object in my array controller. If I add an object or remove an object from the array controller the table updates accordingly.
However... I was under the impression that my PersonModel object would be available from within my NSCell subclass. But I don't know how to get to it. I don't want to set each NSCell using setters and getters because then I'm breaking the whole model concept by storing data in the NSCell instead of referencing it from the array controller.
And yes I do need to have a custom NSCell, so having multiple columns is not an option. Where to from here?
In addition to the Google and StackOverflow search, I've done the obligatory walk through on Apple's docs and don't seem to have found the answer. I have found a lot of references that beat around the bush but nothing involving an NSArrayController. The controller makes life very easy when binding to other elements of the model entity (such as a master/detail scenario). I have also found a lot of references (although no answers) when using Core Data, but Im not using Core Data.
As per the norm, I'm very grateful for any assistance that can be offered!
Finally figured this one out. Man that took some doing. So here is what I needed to do...
First of all I needed to create an array of my model's key values in my model object and return those key values in an NSDictionary from within the model.
Thus my model got two new methods as follows (based on my simplified example above):
+(NSArray *)personKeys
{
static NSArray * personKeys = nil;
if (personKeys == nil)
personKeys = [[NSArray alloc] initWithObjects:#"firstName", #"lastName", #"gender", #"age", nil];
return personKeys;
}
-(NSDictionary *)personDictionary
{
return [self dictionaryWithValuesForKeys:[[self class] personKeys]];
}
Once implemented, I assign my bound value in my table to
arrayController --> arrangeObjects --> personDictionary.
The last step is to reference the object in the NSCell drawWithFrame and use as needed as follows:
NSDictionary * thisCellObject = [self objectValue];
NSString * objectFirstName = [thisCellObject valueForkey:#"firstName"];
NSString * objectLastName = [thisCellObject valueForKey:#"lastName"];
And as I hoped, any update to the model object reflects in the custom NSCell.
There is another approach that does not require the dictionary. However, it does require the implementation of the - (id)copyWithZone:(NSZone *)zone method within your data class. For example:
- (id)copyWithZone:(NSZone *)zone {
Activity *copy = [[self class] allocWithZone: zone];
copy.activityDate = self.activityDate;
copy.sport = self.sport;
copy.sportIcon = self.sportIcon;
copy.laps = self.laps;
return copy; }
Now in IB, you point the Table Column's value at Array Controller --> arrangedObjects
The drawWithFrame method will now return your actual object from the objectValue.
Activity *rowActivity = [self objectValue];
Changing the class requires updating the copyWithZone method and then accessing the data directly in your drawWithFrame method.
I'm very grateful for this post, Hooligancat, because my project was stalled on this problem, and as hard as I looked at Tim Isted's identical solution at http://www.timisted.net/blog/archive/custom-cells-and-core-data/
I couldn't figure it out.
It was only when I read your excellent simplification of the problem and your version of the solution that the penny dropped - I'm very grateful!