CD's been an enormous learning curve for me and there's still a bit for me to go, but any help on the following could enable me to lift the current weight on my shoulders!
I'm trying to write a method that implements a "Save As.." for the user in my CD app.
So far I've got:
[saveAsPanel beginSheetModalForWindow:window completionHandler:^(NSInteger userResult)
{
if (userResult == NSOKButton) {
NSPersistentStoreCoordinator *psc = [self persistentStoreCoordinator];
NSURL *oldURL = [self URLOfInternalStore]; //returns the current store's URL
NSURL *newURL = [saveAsPanel URL];
NSError *error = nil;
NSPersistentStore *oldStore = [psc persistentStoreForURL:oldURL];
NSPersistentStore *sqLiteStore = [psc migratePersistentStore:oldStore
toURL:newURL
options:nil
withType:NSXMLStoreType
error:&error];
}
}];
Unfortunately, I just get the error:
Object's persistent store is not reachable from this NSManagedObjectContext's coordinator.
Should I 'remove' and then 'addPersistentStore...' to update it to the new URL? The doc's seem to suggest that all will be handled with in the 'migrate' method.
Thanks in advance!
Edit:
Ok, well, I've come up with my own 'dirty' method. I can imagine that this isn't an approved way of doing things, but there's no error thrown up and the app works as expected at all times (not often I can say that, either!):
-(IBAction)saveAsAction:(id)sender
{
NSSavePanel *saveAsPanel = [NSSavePanel savePanel];
[saveAsPanel beginSheetModalForWindow:window completionHandler:^(NSInteger userResult)
{
if (userResult == NSOKButton) {
[self saveAction:#"saveAsCalling"];
NSURL *newURL = [saveAsPanel URL];
NSError *error = nil;
[[NSFileManager defaultManager] copyItemAtURL:[NSURL fileURLWithPath:internalStore] toURL:newURL error:&error];
//internalStore is a hard-wired NSString that holds the path to the bundle's database
}
}];
}
-(IBAction)loadAction:(id)sender
{
NSOpenPanel *loadPanel = [NSOpenPanel openPanel];
[loadPanel beginSheetModalForWindow:window completionHandler:^(NSInteger userResult)
{
if (userResult == NSOKButton) {
[self saveAction:#"loadCalling"];
NSURL *newURL = [loadPanel URL];
NSURL *oldURL = [NSURL fileURLWithPath:internalStore];
NSError *error = nil;
NSPersistentStoreCoordinator *psc = [SELF_MOC persistentStoreCoordinator];
[psc removePersistentStore:[[self persistentStoreCoordinator] persistentStoreForURL:oldURL] error:&error];
[psc addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:newURL options:nil error:&error];
[[NSFileManager defaultManager] removeItemAtURL:oldURL error:&error];
[[NSFileManager defaultManager] copyItemAtURL:newURL toURL:oldURL error:&error];
[psc removePersistentStore:[[self persistentStoreCoordinator] persistentStoreForURL:newURL] error:&error];
[psc addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:oldURL options:nil error:&error];
}
}];
}
The basic reasoning is this: to do a 'SaveAs...' I simply copy out the SQLLite store file in the mainBundle to wherever the user selects and rename it to what they want - as per TechZen's suggestion.
To do a 'Load' then I first removePersistentStore from the bundle's file, add the one that the user's just chosen. Delete the bundle store (which in theory isn't now being used) and then copy the user's choice back into the bundle. Finally, the two operations of remove and addPersistentStore are performed to point the app back to it's bundle's file which is now the user's choice.
Hope that makes sense. If anyone has any thoughts on just how unprofessional a methodology this is then please - be kind as I'm fairly new - let me know. I can't find anything that is more elegant.
I know Apple don't like you using removePersistentStore and addPersistentStore but, as I say no errors are reported (in my actual code I scattered NSLog lines throughout to report what error is holding).
You only use a SaveAs... in a document based app. If you use Core Data as your model, you need to use NSPersistentDocument to save your data. It provide the SaveAs... functionality you seek.
Straight Core Data is used for more database-like apps in which the entire app operates from one data set (more or less.)
Related
Ok, yes I know now that you can not use hardcoded paths with sandbox. Up to this point I have not delt with sandbox, so I never encountered it.
I have a Coredata App (Mac OSx) and I used the default save code and the default path location (user/...../applicationsupport/... This, of coarse, is not acceptable in the sandbox.
Without requiring the user to manually open the data file each time the program is launched, is there another way to deal with this?
I would appreciate any input/suggestions.
Thanks You
Sandbox doesn't mean there isn't any access to files and folders without user selection. As it said in App Sandbox in Depth article there's container directory you still having access to.
For taking a path to your Application Support-directory you should use the same code whenever you use Sandboxing or not.
+ (NSString *)executableName
{
NSString *executableName = [[[NSBundle mainBundle] infoDictionary] objectForKey:#"CFBundleExecutable"];
if(!executableName || executableName.length==0)
return nil;
return executableName;
}
- (NSString *)findOrCreateDirectory:(NSSearchPathDirectory)searchPathDirectory
inDomain:(NSSearchPathDomainMask)domainMask
appendPathComponent:(NSString *)appendComponent
error:(NSError **)errorOut
{
NSArray *paths = NSSearchPathForDirectoriesInDomains(searchPathDirectory,domainMask,YES);
if ([paths count]==0)
return nil;
NSString *resolvedPath = [paths objectAtIndex:0];
if (appendComponent)
resolvedPath = [resolvedPath stringByAppendingPathComponent:appendComponent];
NSError *error;
BOOL success = [self createDirectoryAtPath:resolvedPath withIntermediateDirectories:YES attributes:nil error:&error];
if (!success)
{
if (errorOut)
*errorOut = error;
return nil;
}
return resolvedPath;
}
- (NSString *)applicationSupportDirectory
{
NSError *error;
NSString *result = [self findOrCreateDirectory:NSApplicationSupportDirectory inDomain:NSUserDomainMask
appendPathComponent:[self executableName] error:&error];
if (error)
return nil;
return result;
}
-- a question about how to make an object that is saved to the documents directory persist on the drive and be recoverable after the iDevice is rebooted.
Here's my problem. I make a data object with NSCoding and fill it with data. I write it to the documentsDirectory each time the data in the object are updated. I stop the app and start the app again, and my data object persists, with all of its data. But if I reboot the iPhone the code I wrote to recover and read the data object fails.
The code I wrote originally used only a NSString for the file path. It worked well under ios7 but it fails under ios8.
Reading up on things, I found this clue from the Apple documentation:
"Important: Although they are safe to use while your app is running, file reference URLs are not safe to store and reuse between launches of your app because a file’s ID may change if the system is rebooted. If you want to store the location of a file persistently between launches of your app, create a bookmark as described in Locating Files Using Bookmarks."
So I rewrote my ios7 file open and file close methods so they no longer use strings or urls but get their strings and urls from a bookmark that is saved using NSUserDefaults. Same problem: everything works fine so long as I do not power off the phone, but all is lost once I do. I am not able to solve this.
Here is my current series of steps. First I either determine (or if it already exists in NSUsrDefaults, I recover) the absolute path to the documentsDirectory, using a bookmark:
+ (NSString*) getGeoModelAbsolutePath
{
NSString *path;
NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
NSURL *documentsDirectoryBookmarkURL;
NSData* documentsDirectoryBookmark = [userDefaults objectForKey:#"documentDirectoryBookmark"];
if(documentsDirectoryBookmark == nil)
{
documentsDirectoryBookmarkURL = [self getDocumentsDirectoryURL];
documentsDirectoryBookmark = [self bookmarkForURL:documentsDirectoryBookmarkURL];
}
documentsDirectoryBookmarkURL = [self urlForBookmark:documentsDirectoryBookmark];
path = documentsDirectoryBookmarkURL.path;
path = [path stringByAppendingString:#"/Model.mod"];
return path;
}
using methods modified from my ios7 code (which used only the getDocumentsDirectory method):
+ (NSString *)getDocumentsDirectory
{
NSURL *directory = [self getDocumentsDirectoryURL];
NSString * documentsDirectory = directory.path;
return documentsDirectory;
}
And
+ (NSURL *)getDocumentsDirectoryURL
{
NSURL *directory = [[[NSFileManager defaultManager]
URLsForDirectory:NSDocumentDirectory
inDomains:NSUserDomainMask]
lastObject];
return directory;
}
And
+ (NSData*)bookmarkForURL:(NSURL*)url {
NSError* theError = nil;
NSData* bookmark = [url bookmarkDataWithOptions:NSURLBookmarkCreationSuitableForBookmarkFile
includingResourceValuesForKeys:nil
relativeToURL:nil
error:&theError];
if (theError || (bookmark == nil)) {
// Handle any errors.
return nil;
}
return bookmark;
}
So now I have a NSString path with the model filename that I can use to get to the GeoModel
- (GeoModel*) openGeoModel
{
GeoModel *geoModel;
NSString* documentsDirectoryGeoModel =[FileManager getGeoModelAbsolutePath];
if([FileManager fileExistsAtAbsolutePath:documentsDirectoryGeoModel])
{
NSData* data = [NSData dataWithContentsOfFile: documentsDirectoryGeoModel]; //]documentsDirectoryGeoModel];
geoModel = [NSKeyedUnarchiver unarchiveObjectWithData: data];
NSString *unarchivedGeoModelVersion = geoModel.geoModel_VersionID;
if(![unarchivedGeoModelVersion isEqual: currentGeoModelVersion])
{
[FileManager deleteFile:documentsDirectoryGeoModel];
geoModel = [GeoModel geoModelInit];
[Utilities setGeoProjectCounter:0];
}
}
else
{
geoModel = [GeoModel geoModelInit];
}
[FileManager saveGeoModel];
return geoModel;
}
Which I then can save to the documentsDirectory as follows:
+ (BOOL)saveGeoModel
{
NSError *error = nil;
NSString *path = [self getGeoModelAbsolutePath];
[NSKeyedArchiver archiveRootObject:appDelegate.currentGeoModel toFile:path];
NSData* encodedData = [NSKeyedArchiver archivedDataWithRootObject: appDelegate.currentGeoModel];
BOOL success = [encodedData writeToFile: path options:NSDataWritingAtomic error:&error];
return success;
}
Which is always successful -- but is persistent only if I do not turn off the device! I am not making any progress with this: Any help would be much appreciated!
Thanks in advance
Tim Redfield
There. I think it is answered -- unless someone else has a comment on how to improve the above listings, they DO work as they ought to!
i have this code working on IOS7, its check if an image exist in device and if not, it download locally.
Now on IOS8 doesnt save nothing, could someone help me?
//folder where save
NSString *ImagesPath = [[NSString alloc] initWithString:[[[[NSBundle mainBundle] resourcePath] stringByDeletingLastPathComponent] stringByAppendingPathComponent:#"Documents"]];
// check if image exist
NSString* foofile = [ImagesPath stringByAppendingPathComponent:nombreImagenLocal];
BOOL fileExists = [[NSFileManager defaultManager] fileExistsAtPath:foofile];
// check if image exist locally
if (!fileExists){
NSData *data = [NSData dataWithContentsOfURL:[NSURL URLWithString:rutaCompletaLogo]];
//if not, i save it
if (data) {
// url where is saved
NSString *cachedImagePath = [ImagesPath stringByAppendingPathComponent:nombreImagenLocal];
if ([data writeToFile:cachedImagePath atomically:YES]) {
NSLog(#"Downloaded file saved to: %#", cachedImagePath);
}// end
The path to 'Documents' folder has changed from iOS8. Check the Apple tech note
Please, make sure you don't use hardcoded values. Use the methods provided by the API:
NSString *resourcePath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];
OR (as stated in the previous link)
// Returns the URL to the application's Documents directory.
- (NSURL *)applicationDocumentsDirectory{
return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
}
Hope this helps!
I am trying to write the data of core data to a xml file.
What is the best way? Using an arraycontroller which propably could provide the data?
Or try with NSFetchRequest? I tried the last but I think the output of the NSFecthRequest can not written to a xml file.
I used this code:
NSManagedObjectContext *moc = [self managedObjectContext];
NSEntityDescription *entityDescription = [NSEntityDescription entityForName:#"LanguageEntity" inManagedObjectContext:moc];
NSFetchRequest *request = [[NSFetchRequest alloc] init];
[request setEntity:entityDescription];
[request setReturnsObjectsAsFaults:NO];
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"1==1"];
[request setPredicate:predicate];
NSSortDescriptor *descriptor = [NSSortDescriptor sortDescriptorWithKey:#"language" ascending:YES];
request.sortDescriptors = [NSArray arrayWithObject:descriptor];
NSError *error;
NSArray *array = [moc executeFetchRequest:request error:&error];
NSLog(#"%#", array);
if (array == nil)
{
NSLog(#"error");
}
else
{
NSString *root = #"/Users/Sebastian/Desktop/A6/A6/newPlist.xml";
if (![[NSFileManager defaultManager]fileExistsAtPath:root])//checking fileexist or not
{
//if not exist creating the same
[[NSFileManager defaultManager]createFileAtPath:root contents:nil attributes:nil];
[[moc executeFetchRequest:request error:&error] writeToFile:root atomically:YES];
}
else
{
[[moc executeFetchRequest:request error:&error] writeToFile:root atomically:YES];
}
}
Is this mainly the correct way? Or should I use an ArrayController? And if so can you tell me please how to do?
Later I want to be able to save the core data content to an xml file and load an other xml or something particular.
Kind regards
How you get the data is really beside the point. Your issue is with converting the data into a form which can be exported to XML and how you process that data.
By using:
[[moc executeFetchRequest:request error:&error] writeToFile:root atomically:YES];
(firstly you are re-executing a fetch that you have already executed) you are trying to directly convert an array of managed objects into XML (in a plist format). This isn't necessarily going to work because a plist has a very specific set of allowed data types, and managed objects aren't one of them.
You could change the fetch to return dictionaries (NSDictionaryResultType), and this would get you closer. But, any dates in the data you fetch would still cause it to fail. If you have any data types that can't be stored into a plist then you will need to perform a conversion into another data type before you try to convert the array.
Is there a way to delete all the records from an NSManagedObjectContext?
I'm using the following code to insert data:
NSManagedObjectContext * context = [[NSApp delegate] managedObjectContext];
NSManagedObject * basket = nil;
basket = [NSEntityDescription insertNewObjectForEntityForName:#"ShoppingBasket"
inManagedObjectContext: context];
[basket setValue:[firstSelectedObject valueForKey:#"accessoryID"]
forKey: #"accessoryID"];
How do I delete all the records? I want something that's like the "remove:" function, but to remove everything.
To delete all instances of a given entity (we'll use your ShoppingBasket), you can simply fetch all baskets then delete them. It's just a few lines of code:
NSManagedObjectContext * context = [self managedObjectContext];
NSFetchRequest * fetch = [[[NSFetchRequest alloc] init] autorelease];
[fetch setEntity:[NSEntityDescription entityForName:#"ShoppingBasket" inManagedObjectContext:context]];
NSArray * result = [context executeFetchRequest:fetch error:nil];
for (id basket in result)
[context deleteObject:basket];
The alternative in a non-document-based app is to shut down your connection to the data store, delete the actual file, then reconnect (the template code that comes with a standard Core Data project will automatically create the file if it's absent). You then have a brand new, empty store.
Note, the code example ignores any possible error. Don't do that. :-)
A much quicker way would be to just remove store entirely. This way you're not wasting any time fetching objects, or enumerating through them as the other answer does.
NSError *error;
NSURL *applicationDocumentsDirectory = [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
NSURL *storeURL = [applicationDocumentsDirectory URLByAppendingPathComponent:#"MyCDStore.sqlite"];
[[NSFileManager defaultManager] removeItemAtPath:storeURL.path error:&error];
Don't forget to re-create it after you have deleted it.