I have written different parsers and different NSDocument subclasses for files with different extensions to visualize the data. I would like to intergrate them together into one application. I am using NSDocument architecture. I am not sure how to map files identified by file extensions to its NSdocument object.
I have tried to add document types in the Xcode info session with class and extensions. However, it seems that it always execute the same parser regardless of the file's extension.
1)Subclass NSDocumentController
a)in your XIB with mainmenu put a new object and give it a class of your new NSDocumentController subclass
or
b)create a new instance before appDidFinishLaunching (initialize, load...)
2)override methods as you see on picture (those which determine type and return document instances) to provide new document instances (as per type)
Read more here
Also scan with your eyes NSDocumentController.h (CMD+SHIFT+O and type NSDoc...)
Related
I have a class which as its properties has a number of NSSet values. The content of these sets is not stored in Core Data, but comes from another source. They are basically ID strings which are unique. No point in filling up Core Data with them as separate entities.
However, as far as I can see it's not possible to store an NSSet as an attribute of an NSManagedObject. I guess I would need to serialise it into binary data by hand, whenever the object gets stored, and deserialise it when it gets retrieved from the persistent store? The same would also apply to storing other collection classes.
Has anybody else ever come across this issue and is able to give some advice?
You can set the attribute type to 'transformable' and then directly store the set into the attribute. Be sure that all of the contents of the set conform to < NSCoding >.
In Xcode, in the Project Navigator open up the project_name.xcdatamodeld source for the model editor and select the entity in question. Choose Editor in the Xcode menu bar and there is a Create NSManagedObject subclass... item. Make the subclass and use it for extra non-Core Data properties. The subclass becomes part of the model in place of the entity. It retains all of the entity's behaviors.
I'm working on my first Cocoa application, and I'm hoping very much that
[NSWindowController loadWindow]: failed to load window nib file 'Genius Document'
means that there's something very specific I've done wrong, because if I have to go back and redo all the bindings I'll want to kill myself.
FWIW, I'm working with a document-based application that has (so far) only one XIB file and no NIB files.
I can post code/screenshots of my bindings but in case that's not necessary I didn't want to make people wade through them.
Thanks for the help.
The error you have described ultimately occurs because a call to load the nib file is failing. Make sure you've supplied the correct name for your Interface Builder file.
You can supply the correct value in a number of ways (depending on your use of AppKit), so I'll lay out the two most common possibilities and you can track down which one applies to you. Given what you've said in your question, I suspect you'll be dealing with the first scenario.
NSDocument windowNibName
If you are relying on the document architecture's defaults, you are probably not making the call in question directly. Instead, the framework makes the call on your behalf, using whatever nib name you specify on the given document class.
For example, if you were to make a new document-based project with a document class of "XYZDocument," the Xcode template would provide you with a basic XYZDocument class and a XYZDocument.xib file. The XYZDocument implementation file would have the following in it:
// XYZDocument.m
- (NSString *)windowNibName {
return #"XYZDocument"; // this name tells AppKit which nib file to use
}
If you were to alter this value, you would create the [NSWindowController loadWindow] error.
NSWindowController initialization methods
If you are making this call yourself (perhaps on your own subclass of NSWindowController), then you will have written a line like the following.
// XYZWindowController.m (a subclass of NSWindowController)
- (id)init {
self = [super initWithWindowNibName:#"XYZDocument"];
if (self) {
// initializations
}
return self;
}
If the string argument you've supplied does not match the name of the nib file, the same error will occur.
I ran a Clean (Cmd-Shift-K) in Xcode and that solved the issue for me.
I need to be able to compare two versions of a plist file created with NSKeyedArchiver. In particular, it's the "elements" file created in Xcode for a .xcdatamodeld file.
Since I have not created this file myself I can not recreate its object model. Instead, I need to understand which classes and keyed properties the archive contains.
Ideally, I want to create a tree containing strings representing the names of classes along with their property names and values. I assume that all this information is stored in the archive, so it should be possible to generically parse this archive, right?
I've read about NSKeyedUnarchiver and its delegate. I've only gotten as as as this:
Unarchive the file data:
NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:data];
unarchiver.delegate = self;
id graph = [unarchiver decodeObjectForKey:#"root"];
Here's the delegate method that gets called when an unknown class is requested. I return a proxy class here in which I hope to collect its values:
- (Class)unarchiver:(NSKeyedUnarchiver *)unarchiver cannotDecodeObjectOfClassName:(NSString *)name originalClasses:(NSArray *)classNames
{
NSLog(#"wants: %#", name);
return [ObjProxy class];
}
The proxy class implements
- (id)initWithCoder:(NSCoder *)aDecoder
in which I do not know how to proceed, not knowing the actual properties of the classes. NSCoder doesn't seem to provide any function to learn of the available keys. Is there a trick to get to them, maybe by overriding some of the lower level objc methods?
So far, with this little code shown above, when parsing the "elements" file, I only get the request for one class, "XDPMModel", and then it's done.
Any ideas how to get this working, i.e. traverse the tree deeper?
You can use PlistExplorer, it's a Cocoa Tool to inspect files written by NSKeyedArchiver.
I've done exactly this before, to decode objects stored in the preferences file for Panic's Coda. What I did was to use class-dump on the app (in your case Xcode and its related frameworks), which allows you to see the properties of the real objects, and use these to create proxy objects that match those properties. You can then use NSKeyedUnarchiver successfully and query the proxy objects for their values.
It's a fairly laborious process but it works perfectly. In my case I was working with a user defaults plist so I only had to define a couple of these proxy classes for the objects I was interested in, but I would imagine that you'll have to define quite a few for Xcode.
I'd also be very interested to know if there's a way to do this without having to go the class-dump route (possibly, as you say, via some of the lower-level Objective-C functions) because it would greatly simplify this type of reverse engineering.
Ok, I am creating a document-based application in Cocoa and the document's file type is actually a package. Within that package is an XML settings file, a SQLite database and a zip file which is downloaded at runtime. Now the only thing that changes, really, is the XML settings file as the other ones can be recreated at run-time.
Each one of these packages will have one and only one window, hence my desire to use document-based. These files can also be copied, renamed, moved, etc. just like any other file that is part of such an architecture.
But I am completely lost as how to implement this in the Documentation Framework! It seems everywhere I look in the docs it's always talking about in-memory representations of the files which you then write out using the path presented to you in one of the NSDocument overrides (since Cocoa may move it, etc.) But again, I'm using a SQLite database that sits on disk, not in memory.
I have looked all over for overridable methods that would still give me things like dirty-state checking of the doc, open and save file dialog support and the like, but I can't seem to find anything that just says 'Here's a file URL... Open it as you see fit' althought I did get close at the application's delegate level, at least for the opening.
So let's assume that's working as expected. How do I implement the save/save-as where I want to control everything that is written to disk or not? I don't want to (not can I) mess around with data structures or the like. I just want to be given a psth that the user selects in the 'Save As' dialog (for new) and be able to write what I need to there. Simple. But again, the 50+ page document from developer.apple.com about Document-based architecture tells me where to overload a lot of things, but every one seems to stem from some in-memory representation of the document, which again, is not what my package is. Technically, only the internal XML file is what would be tied to the document. Everything else is just support for it.
So? Anyone? Takers?
Mark
I can't seem to find anything that just says 'Here's a file URL... Open it as you see fit'
Implement the readFromURL:ofType:error: method in your document class. Alternatively, since your document type is a package type, implement the readFromFileWrapper:ofType:error: method.
You don't have to read the data into memory; you can do whatever you want in whichever method you implement, including opening the database.
How do I implement the save/save-as where I want to control everything that is written to disk or not?
Implement the writeToURL:ofType:error: method or the fileWrapperOfType:error: method.
If you had or could easily create data in memory, you would implement the readFromData:ofType:error: and dataOfType:error: methods. The URL-based and file-wrapper-based methods are for cases where data in memory is not an option. And the primary use of file wrappers is for package types like yours.
Actually, I found it. It's not the 'writeTo' methods, but rather the 'saveTo' methods you want to override. When I did that, the saving code worked as I expected, including automatic save panel support. For clarity, this is the one I chose...
saveToURL:ofType:forSaveOperation:error:
and it works like a champ! Not too confusing now, was it! Sheesh!!!
That was of course the very first thing that I tried, but if you read the developer documentation--specifically the Cocoa Document-Based Architecture--here's what it says about those very methods...
During writing, your document may be asked to write its contents to a different location or using a different file type. Again, your overridden method should be able to determine everything it needs to do the writing from the passed-in parameters.
If your override cannot determine all of the information it needs from the passed-in parameters, consider overriding another method. For example, if you see the need to invoke fileURL from within an override of readFromData:ofType:error:, perhaps you should instead override readFromURL:ofType:error:. For another example, if you see the need to invoke fileURL from within an override of writeToURL:ofType:error:, perhaps you should instead override writeToURL:ofType:forSaveOperation:originalContentsURL:error:.
In other words, it seems to say that you can't assume the URL that is passed to you is the actual place on disk where the 'something' is eventually written to, which wreaks havoc when dealing with database files that are opened by URL. Maybe I'm missing something.
But ok... forget I read that and simply even try to just override those methods. I do and return TRUE for each, (I log the URL so I can see what is being passed in), I get this error on 'Save As' after you have chosen a filename...
2009-10-28 14:31:51.548 XPanel[1001:a0f] dataOfType:error: is a subclass responsibility but has not been overridden.
...but when you look at the documentation for that it says the default implementation throws an exception because you must override one of the other implementations above... which I obviously just did! Plus, again, this can't be represented as simple data!
So grasping at straws here, I overrode that one too and just returned nil, since again, you can't represent what I'm doing with a NSData object. Then I get a 'Can't be saved' message.
WTF?! Why is it calling that thing anyway??!!
...and that's when I gave up and posted this here.
Now if YOU can give me a simple example that perhaps doesn't even actually read or write a file but instead just logs the URL, that would be perfect. Not to useful but still, it should work... I just can't seem to implement get it to.
I'm trying to figure out how to decide when to use NSDictionary or NSCoder/NSCoding?
It seems that for general property lists and such that NSDictionary is the easy way to go that generates XML files that are easily editable outside of the application.
When dealing with custom classes that holds data or possibly other custom classes nested inside, it seems like NSCoder/NSCoding would be the better route since it will step through all the contained object classes and encode them as well when an archive command is used.
NSDictionary seems like it would take more work to get all the properties or data characteristics to a single level to be able to save it, where as NSCoder/NSCoding would automatically encode nested custom classes that implement the NSCoding interface.
Outside of it being binary data and not editable outside of your application is there a real reason to use one over the other? And along those lines is there an indicator of which way you should lean between the two? Am I missing something obvious?
Apple's documentation on object graphs has this to say:
Mac OS X serializations store a simple hierarchy of value objects, such as dictionaries, arrays, strings, and binary data. The serialization only preserves the values of the objects and their position in the hierarchy. Multiple references to the same value object might result in multiple objects when deserialized. The mutability of the objects is not maintained.
…
Mac OS X archives store an arbitrarily complex object graph. The archive preserves the identity of every object in the graph and all the relationships it has with all the other objects in the graph. When unarchived, the rebuilt object graph should, with few exceptions, be an exact copy of the original object graph.
The way I interpret this is that, if you want to store simple values, serialization (using an NSDictionary, for example) is a fine way to go. If you want to store an object graph of arbitrary types, with uniqueness and mutability preserved, using archives (with NSCoder, for example) is your best bet.
You may also want to read Apple's Archives and Serializations Programming Guide for Cocoa, of which the aforelinked page on object graphs is a part, as it covers this topic well.
I am NOT a big fan of using NSCoding/NSCoder/NSArchiver (we need to pick a name!) to serialise an object graph to a file.
Archives created in this way are incredibly fragile. If you save an object of class Foo then by golly you need to make sure when you load the data back in you have a class Foo in your application.
This makes NSCoder based serialisation difficult from the perspective of sharing files with other applications or even forwards compatibility with your future application.
I forgot to list what I would recommend.
NSCoding can be ok in certain situations: if you're just doing something quick and simple (although you do have to write a lot of code - two methods per class to be serialised). It can also be ok if you're not worried about compatibility with other applications.
Export/import via property lists (perhaps using the NSPropertyListSerializaion class) is a fine solution. XML based plists are easy to create and edit. Main advantage to plists is that you're not tying the file format to just your application.
You can also create your own XML based file format and read/write to it using NSXMLDocument API and friends. This really isn't much more work than using property lists.
I think you're a bit confused, NSDictionary is a data structure, it also happens to implement the NSCoding protocol. So in essence, you could either put all your data into a NSDictionary and have that encode itself later on, or you can implement the NSCoding protocol and encode your object tree using the NSCoder API. Based on the type of NSCoder object passed in to the encodeWithCoder: method, is the output of your encoding.