I have a tableview with 9 cells and in each cell i have at least 2 textfields. Each cell has a label, and the textfields.placeholder are the same in each cell:(example foto below)
I already created the entities in core data (which are the labels) and the attributes for each one ( which are the textfields.placeholder):
My question is, how can i set the textfield.text to each attribute in each entity? how to distinguish the textfields?....i don´t think that the IF statment is the best approach ( it would be a LOT!!), and the other problem is the cells are dynamic ( so the user can add more kind of trousers for example)...
Any ideas would be most appreciate... i´m really stuck!.
Thanks in advance.
I´ve been reading a little, but i´m having trouble understanding something: When you say "you can set an object for each cell" are your referring to the classes that core data automatically creates for each entity(when you hit subclass NSmanageobject button),and then i should bind the texfields from each cell to an object of each entity class??.I already have the classes that are referring to each cell, and then i think i should be doing this: Trousers *trouse = [NSEntityDescription insertNewObjectForEntityForName:#"Trousers" inManagedObjectContext:self.managedObjectContext]; trouse.nameProduct =Textfield.text.and this is the part i don´t no the best approach, because i have more than one textfield in each cell(and i din´t make them property´s of my view) and doing like this, it will be an enourmous amount of work! Can you help me understand better?.
If you are using CoreData with a table view you should be hooking up model objects to the UI using NSFetchedResultsController
Have a look at the documentation and examples for this. It's designed to make this sort of thing less painful.
Related
I am refactoring an old web app into React and Material-UI, and I find myself stuck when trying to find the proper way of presenting a "property table". I have looked into several data table implementations, but neither a data table nor Material-UI's List seems to be the right tool for the work.
Data tables are meant for each row having the same properties (columns) repated for different entities, whilst I need a kind of table where each row is a key+value presentation. I will call it a property table unless someone can tell me there is already a better name.
Below is a picture of current view in the refactored app (contains only test data). I realize I might need to think differently and not just copy the old structures.
So what would be the correct way to present a similar list of properties with Material Design?
I seem to find no explicit component or view type for my "property table", so I will simply make a table with Material-UI <Table>component, and skip the header.
I have two windows, one is a table view to display content. One is a window for inputting content.
I have an NSTextField binded to a property in my app delegate. When I change a value in the text field, the app delegate property will change. However, if I go the other way and programmatically change the property's binded key, the value of the text field does not update. However, it does in the table view.
What is going wrong here? How can I update text field?
EDIT:
I tried all 3 of these with the same result
[_addEntry setValue:#"Chet" forKey:#"payee"];
[_addEntry setPayee:#"chet"];
_addEntry.payee = #"chet";
EDIT:
Here's a simple example to elaborate on my point
https://dl.dropboxusercontent.com/u/48014761/test.zip
the label and the textfield are bound to the "str" property. It is initially null. press log to see that in the console. press change str button to change the string. Log to verify. Note that the label and the textfield do not update!
EDIT:
"What am I trying to accomplish?"
Here's the project I am working with:
https://dl.dropboxusercontent.com/u/48014761/Write-Offs.zip
I am trying to use Cocoa Bindings as much as possible. I have a table with a bunch of data. However, each entry is going to have an array of images associated with it. Thus, when I add a new entry, I need to open up a new window so I can set the properties of that entry (rather than through the table) along with upload some images.
I am not sure I am implementing the addEntryWindow correctly. It seems like I should create and destroy the window each time I open and close it. This doesn't appear to be happening.
Also, [[self addEntry] setDate:[NSDate date]]; doesn't seem to fix the problem for me.
Thanks
Chet
How are you programmatically changing the field? Are you using KVO? Is the field inside of a NSManagedObject instance?
Bindings work through KVO. Core Data disables some aspects of KVO for its own internal uses and you might be tripping over one of those.
Update your question with the code sample and lets see what is going on.
Update
Both windows don't necessarily need to be in the same xib but they do need to be talking to the same instances. Ideally they should both be talking to the same instance of NSManagedObject and therefore talking to the same NSManagedObjectContext.
Who is the owner of each window?
Is the owner the same?
If not, is a new Core Data stack being created?
Update
In your test, I was able to correct it by how you were editing the property
- (IBAction)press:(id)sender {
[self setStr:#"this"];
}
You were accessing the iVar directly instead of the property. When you access the iVar directly KVO does not fire.
In addition, in your xib files you were accessing self.str which is unnecessary. It should be just str.
Are you doing any direct property access in your actual project?
Update
You can do a get accessor and then a set accessor:
[[self addEntry] setPayee:xxx];
Based on the variables you are using I wonder what you are trying to accomplish. Can you post the exact code of the programmatic change you are trying to enact?
I am having a very hard time understanding what needs to be included in the Children Views in order to perform a fetch request and display the results in a table view when using Core Data. All the examples I have found are either only one layer deep (Random Dates), using the Root View Controller which always works, or using several view controllers with pictures and other attributes (Recipes) that make it confusing for me to follow.
An example of what I am looking for would be an Entity with three attributes. The entity is album and the three attributes are albumTitle, albumArtist and yearRecorded.
Now in my Navigation app my Root View Controller has three rows to choose from not using the Entity or Core Data at all. The three choices are "Title", "Artist" and "Year". When you click on one of the three rows it will push a new view controller and list all of the appropriate attributes in a new table view.
I believe it should be very simple and not require too much code but I can't get a handle on it. Any explanations or sample code is greatly appreciated.
You could just make a fetch request with no predicates to get all the objects from your Core Data store, so, you'll have an array of songs.
Than you just call, for example, [fetchedSongs valueForKeyPath:#"artist"]; to get an arry of artist and add it as a source to your tableview.
I've got a few questions I've been trying to answer for myself (by hunting through the documentation) but I have a feeling I'm missing something.
Any hints (and/or pointers to appropriate documentation) would be much appreciated.
I'm building a Core Data document-based application. There are essentially two entities:
There is a single "Comparison" record associated with each document.
There are potentially many "Node" records associated with each document.
My first question is whether I'm thinking about this correctly. Since there is only a single Comparison object for each document, the attributes of the Comparison are essentially attributes of the Document itself. What (if any) is the preferred way of modeling that?
If a Comparison entity is in fact the right way to go, my next question is how and when to actually instantiate the (single) Comparison object. The user should not have to explicitly "add" the Comparison since there's going to be only one of them associated with the Document. Instead, a single Comparison object should be instantiated and inserted into the managedObjectContext. I've got something like this working already, with code in MyDocument.m that looks like this:
(void)windowControllerDidLoadNib:(NSWindowController *)windowController {
[super windowControllerDidLoadNib:windowController];
[NSEntityDescription insertNewObjectForEntityForName:#"Comparison" inManagedObjectContext:managedObjectContext];
}
However -- if the user creates a new document but then never does any work with it -- for example if he immediately clicks the close button -- then he should not be asked to "Save" the document. He should be asked to save his work only if he's actually entered any information. Is there a preferred way to implement this behavior?
I found this thread while struggling with the exact same issue. I have a table of Entity_A working in my document based Core Data app, but I need to figure out how to handle a required single-instance per document of Entity_B.
I've found something that seems to work. There's probably a better way, but this is getting me past this hurdle for now.
When the document's xib is loaded I simply check to see if an Entity_B has been created. if not, I create one and initialize its attributes.
- (void)windowControllerDidLoadNib:(NSWindowController *)aController
{
[super windowControllerDidLoadNib:aController];
//has an Entity_B been created? if not, create one.
NSError *theError = nil;
NSUInteger count = [[self managedObjectContext] countForFetchRequest:[NSFetchRequest fetchRequestWithEntityName:#"Entity_B"] error:&theError];
if( count == 0 )
{
NSManagedObject *newEntity_B = [NSEntityDescription insertNewObjectForEntityForName:#"Entity_B" inManagedObjectContext:[self managedObjectContext]];
[newEntity_B setValue:[NSNumber numberWithBool:YES] forKey:#"boolAttribute"];
[newEntity_B setValue:[NSNumber numberWithInt:2] forKey:#"intAttribute"];
}
}
I didn't insert that code snippet into the original post correctly. Trying again:
-(void)windowControllerDidLoadNib:(NSWindowController *)windowController {
[super windowControllerDidLoadNib:windowController];
[NSEntityDescription insertNewObjectForEntityForName:#"Comparison" inManagedObjectContext:managedObjectContext];
}
Your question about modelling is not very clear, can you please elaborate on what your "Comparison" entity is supposed to do and what sort of attributes you are assigning to it? It would be handy to see your "Document" entity structure so we can provide some useful input.
With regards to your second question, you could check if your NSManagedObject has been updated before deciding on whether to prompt the user to save their document or not:
if ([documentObject isUpdated]) {
...
}
More details in the documentation here http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/CoreDataFramework/Classes/NSManagedObject_Class/Reference/NSManagedObject.html#//apple_ref/occ/cl/NSManagedObject
Cheers,
Rog
There isn't really a "Document" entity, I was simply using that term to refer to the overall document that is saved when the user invokes the Save menu item. Perhaps there is a better way to refer to this concept? NSPersistentDocument?
Backing up a bit... the central idea of the application is to compare two hierarchical directory structures (a visual recursive "diff").
For now the "Comparison" entity has two string attributes, pathA and pathB, which are the names of the two directories to be compared. Each "Node" entity represents the name of a file down in the directory trees that are being compared. The Node entity contains at least one attribute ("relativePath") which is the path relative to the starting point specified in the Comparison.
My first question was simply whether it makes sense for there to be a "Comparison" entity since there is going to be only one of them instantiated (at some point after the user invokes the "New" menu item).
The second question is really at what point should the single "Comparison" object be instantiated and inserted into the managedObjectContext, i.e. what method is most appropriate to make this happen?
Finally if a "Comparison" object is automatically instantiated (at awakeFromNib time, perhaps?) but the user decides not to proceed, and simply clicks the close button, he should not be prompted to save (right?) What would be the appropriate way to accomplish this? The documentObject will appear to have been updated, because an "empty" Comparison object has in fact already been inserted automatically at startup, but the user has not modified it.
Hope that's clear... thanks.
I have core data app with an entity OBSERVATION that has as one of its attributes DEALNAME.
I want to reference through Interface Builder or by making custom modifications to an NSArrayController a list of unique sorted dealnames so that I can use them in a pop-up.
I have attempted to use #distinctUnionOfSets (and #distinctUnionOfArrays) but am unable to locate the proper key sequence.
I can sort the ArrayController by providing a sort descriptor, but do not know how to eliminate duplicates.
Are the #distinct... keys the right methodology? It would seem to provide the easiest way to optimize the use of IB.
Is there a predicate form for removing duplicates?
Or do I need to use my custom controller to extract an NSSet of the specific dealnames, put them back in an array and sort it and reference the custom array from IB?
Any help would be appreciated. I am astounded that other have not tried to create a sorted-unique pop-up in tableviews.
You need to take a look at -[NSFetchRequest returnsDistinctResults]. That is the level you need to be handling the uniquing of data.
Although I do not have a definitive answer for you, I think there are two ways you can go about it.
The way you already started. You need to bind the contents array of the PopUp button, not just against the arrayController.arrangedObjects, but continue on the path and somehow filter only objects with distinct "DealName"s. This means - the arrayController presents ALL the entities (and may sort them for you) but the PopUp button will have its contents filter via some sophisticated binding to the array controller.
Make your filtering at the ArrayController level (as suggested in another answer here). Here it depends how you set up the array controller. If It is set up to use an "Entity" (vs. "Class") which means the array controller will fetch CoreData entities directly - you can modify its "Fetch" to only bring a subset of the "OBSERVATION" entities with distinct values of "DEALNAME". I don't know how to control WHICH entities are filtered out in this case. Otherwise, you can setup the arrayController to work with "Class" objects, and then you can fetch the entities yourself (in code) and populate the arrayController programmatically, with just the entities you like.
In the second option, the Popup button should be bound normally to the arrayController's arrangedObjects.