i created a nsarraycontroller to display its data on my nstableview. this is working. but how do i modify this data now?
[arrayController addObject:[...]]
adds an object, how do i get it back?
i tried:
NSMutableArray *data = [arrayController mutableArrayValueForKey:#"column1"];]
but then i get this error
2011-05-29 19:25:50.125 TestApp[1665:903] [<NSArrayController 0x113808500> valueForUndefinedKey:]: this class is not key value coding-compliant for the key column1.
(the objects in my arraycontroller representing the rows in my view are of a class (named FileEntry) consisting of 4 properties and i added these as keys to my nsarraycontroller)
i thought kvc-compilant means every attribute has a getter and setter? (and isnt that what properties do?).
i tested my class if i could use this function:
FileEntry *entry = [[FileEntry alloc] initWithUrl:#"test"]; //(this adds the string "test" to the property "fileurl")
NSLog(#"%#\n", [entry valueForKey:#"fileurl"]);
and it returns:
> 2011-05-29 19:31:54.760 TestApp[1718:903] test
and it works. so how can my class not be kvc-compilant?
anyway, i also tried to use the tableviews datasource instead but cant get those 2 functions to work. would that be of more use than the nsarraycontroller? is it even possible to modify data of the nsarraycontroller?
Usually you need a contend array for the NSArrayController to handle, so you could simply take this array and use the NSMutableArray methods. For example you have in your MyController.h a declaration of an array with its setter and getter methods, and you only have to bind the contend array of the array controller to it. Then you can take two buttons for the add and remove methods of the array controller to add something. Now you must bind the value of the column to e.g. FileEntry.fileurl of your array controller managed objects, Now you should be able to add stuff to the table view. And you can also Edit the names in the table view. If you want to get some stuff out of the array in your program somewhere, you can use an outlet of your table view like this:
NSInteger row = [myTableViewOutlet selectedRow];
FileEntry* myEntry = [myArray objectAtIndex:row];
Related
I'm writing my first master detail view in Cocoa. My data model is really simple: just an NSMutableArray that contains instances of a single class having a few NSStrings properties.
Here's what I've created so far:
A class representing the instances.
An NSMutableArray specified as a property of my app delegate to hold the class instances.
A master detail view, with an NSTable and some text fields to hold the properties of a selection instance.
An NSArrayController with a binding specifying the app delegate, and the name of the NSMutableArray property as the model key path.
Bindings between the columns of the NSTable and the NSArrayController (controller key = "arrangedObjects", and model key path of each column = a property of the class).
Bindings between the text fields of the view and the selection (controller key = "selection", and model key path of each text field = a property of the class).
A "+" button and a "-" button in the view to enable adding and removing objects.
However, I'm having two problems with this design:
(1) I can't find a good way to implement the "+" and "-" buttons. First, I bound them to the add: and remove: properties of the array controller. While this seems to work, it has a problem: my class declares an init member that initializes the NSStrings to stub values, but the array controller doesn't seem to [init] the new instances, because the new list entry has empty strings for each column.
Next, I attached them to IBActions in my app delegate that added or removed an object from the NSMutableArray. However, this feels wrong - it feels like I'm violating the model-view-controller architecture by not talking to the array controller. For example, the "-" function has to talk to the array controller to get the selected item. Also, I notice that I have to send a [didChangeValueForKey] message after altering the array - which feels like a signal that I'm doing this wrong.
(2) One of the detail subviews in my view is an NSTextView that's bound to an NSString in the selected object. It really isn't working as expected: when new text is entered, the text remains the same even if other members of the class (which should have different values) are selected. Also, the text data isn't being saved to any instance of the class.
Any thoughts? Thanks in advance.
Here is an example that should be close to what you want:
#import "AppDelegate.h"
#import "Members.h"
#implementation AppDelegate
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification {
self.theData = [NSMutableArray arrayWithObject:[[Members alloc] init]];
}
-(IBAction)addMember:(id)sender {
[self.controller addObject:[[Members alloc] init]];
}
-(IBAction)removeMember:(id)sender {
[self.controller removeObjectAtArrangedObjectIndex:self.controller.selectionIndex];
}
The array controller (whose IBOutlet is controller) has its content array bound to theData. Members is the name of my class that has 3 string properties, name, author and blurb. In the detail view, the 2 text field's are bound to ArrayController.selection.name or author, just like you said you did. The other property, blurb, is bound the same way (ArrayController.selection.blurb), but to the Attributed String value of a text view. This worked fine, I'm not sure what your trouble with the text view was. If I add text to the text view, it does show up there if I click another row in the mater table and then click back (also if I log the array, it shows up there too).
I want to show in a label the current number of elements in an NSArray called pages. Following other guides I did the following:
Created an NSArrayController in IB (called pagesController) and bounded it to the NSArray pages
Bounded the value property of the label to the NSArrayController with Controller Key = arrangedObjects and Model Key Path = #count
The problem is that when the program is running the label always shows "0". To check if the things are working correctly I tried to log a message when the user clicks on another button (the button basically inserts a new element in the pages array): NSLog(#"count = %d", [self.pagesController valueForKeyPath:#"arrangedObjects.#count"]); in this case the output is correct, i.e. the current number of elements in the array printed is correct.
Where am I mistaking?
You many not be using KVC correctly. Your array controller will only be notified with the pages property is redefined, not when objects are added to the array. Try wrapping your code with the appropriate change notifications:
[self willChangeValueForKey:#"pages"];
[pages addObject:someObject];
[self didChangeValueFOrKey:#"pages"];
My CoreData model drives series of UITableViewControllers.
One of the detail tables has a header that contains a UIView "GraphView" that uses data from the rows of the table. (It's like iTunes having a custom header to chart song length in a given playlist.) My "playlist" populates from CoreData correctly. But how do I pass data from the TableView to the UIView in its header?
It seems wasteful and redundant to fetch and parse it again, especially when the data is sitting in a convenient mutable array called "steps". Can I just pass the mutable array to the UIView in the header? If so, how?
I've tried creating an NSArray property in the UIView's class called "passedStepsArray", and then setting it from the StepDetailViewController like so:
graphView.passedStepsArray = [[NSArray alloc] initWithArray:steps copyItems:YES];
But back in the GraphView class, it remains NULL. No value gets passed.
Any ideas?
From my visualization of the problem, it seems you are on the right tracks by having an NSArray property in the GraphView. You probably don't need to copy the existing array using the initWithArray:copyItems: method, just pass a non-mutable copy of the populated steps array:
graphView.passedStepsArray = [[steps copy] autorelease];
This is assuming that the graphView passedStepsArray property is set to retain. (Then don't forget to set self.passedStepsArray = nil; in the graphView dealloc methood.)
I am trying to learn cocoa and have a few problems with KVC and bindings. I have a nstableview with three columns; "checkbox", "text", "icon". The values of each column is binded to an arraycontroller using KVC. When program is launched the rows and columns are correctly filled into the tableview according to the values in the array. I can click a row and correctly print the content of that row using something like this:
- (IBAction)fileTableViewSelected:(id)sender{
NSInteger r;
NSDate *fModOne;
id object;
r = [[NSNumber numberWithInt:[sender selectedRow]] intValue];
object = [arrayIntersect objectAtIndex:r];
fModOne = [object valueForKey:#"fileModifiedDirOne"];
NSLog(#"Date found in row is %#",fModOne);
}
My problem is when I try to click the checkbox in column one and change the value of the box. Initially, the value of the checkbox is set to 1 using the arraycontroller which works fine, but when I want to change the value of the checkbox of a specific row to 0 by clicking on it the program crashes. When the box is clicked an action is correctly called and this is where I thought I could simply change the value of my objects BOOL by calling:
[object setValue:[NSNumber numberWithBool:NO] forKey:#"doSync"];
My setters and getters for the BOOL doSync is defined as:
#property(nonatomic, readwrite) BOOL doSync;
#dynamic doSync;
- (void)setDoSync:(BOOL) value{
NSLog(#"setting dosync %i", value);
doSync = NO;
}
- (BOOL)doSync{
return doSync;
}
I have searched everywhere for a solution to my problem, but I am unable to find any examples of how to use checkboxes in tableview using KVC and bindings. I appreciate any help I can get on this and I would appreciate any examples I could take a look at.
Cheers and thanks! Trond
You don't need to implement this yourself as an action. Just bind the column through your array controller's arrangedObjects to the doSync property of the model objects.
If you don't want to use Bindings, you still shouldn't implement it as an action. Instead, be the table view's data source and respond to the message the table view will send you to change one of the values.
#dynamic doSync;
There's no reason to have this if you turn around and implement the accessors for that property in the same class.
If this is a managed-object class and the property is an attribute of the entity, then your accessors should send [self willAccessValueforKey:] before and [self didAccessValueForKey:] after accessing the instance variable. If that's all they do, then you should not implement the custom accessors at all; cut them out and have #dynamic alone.
- (void)setDoSync:(BOOL) value{
doSync = NO;
That's not setting the property to the value passed in.
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!