I have a chat app with existing sqlite file, now I create a Notification Service Extension and need to share that sqlite file with NSE, so I move existing sqlite to public location with the following code:
NSURL *source = [[Utils applicationDocumentsDirectory] URLByAppendingPathComponent:#"file_name.sqlite"];
NSURL *destination = [[Utils applicationDocumentsDirectoryPublic] URLByAppendingPathComponent:#"file_name.sqlite"];
if ([[NSFileManager defaultManager] isReadableFileAtPath:source.path]) {
BOOL isSuccess = [[NSFileManager defaultManager] moveItemAtURL:source toURL:destination error:nil];
if(isSuccess) {
NSLog(#"movingCoreData success");
}
}
+ (NSURL *)applicationDocumentsDirectory {
NSURL *path = [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
return path;
}
+ (NSURL *)applicationDocumentsDirectoryPublic {
NSURL *path = [[NSFileManager defaultManager] containerURLForSecurityApplicationGroupIdentifier:APP_GROUP];
return path;
}
The sqlite file move success, but some data is lost, and it's not happend for all user (I tried with account A and account B, account A is lost half data (almost is group chat) while account B is fine. And when I fetch data in NSE, it's not return data for me, I see a warning:
CoreData: warning: Unable to load class named 'Conversation' for entity 'Conversation'. Class not found, using default NSManagedObject instead.
Can anyone explain this?
This is probably a result of CoreData using SQLite’s WAL mode by default, which means many of the transactions for the database are stored in a separate file (“...sqlite-wal”). Your copy process does not copy this file, so the transactions go missing.
You could just add another NSFileManager operation to move the WAL file, but as set out in this Technical Q&A it is better to use NSPersistentStoreCoordinator’s migratePersistentStore:toURL:options:withType:error: method.
Related
I am saving video/image in document directory.Now once the image is saved in document directory I want to save its reference in my local database.So I am thinking I can save URL of the image in the local database.
So is it constant throughout my app?
It's not constant, i have observed every time you launch the app it'll be different, but your data is moved to this new path. You can save your file name in your database, and dynamically append this file name to NSDocument directory.
- (NSString *)documentsFilePath:(NSString *)fileName {
NSArray *dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *docsDir = [dirPaths firstObject];
NSString *filePath = [docsDir stringByAppendingPathComponent:fileName];
return filePath;
}
- (void)storeFile:(NSString *)fileName {
NSString *filePath = [self documentsFilePath:fileName];
// create if needed
if (![[NSFileManager defaultManager] fileExistsAtPath:filePath]) {
// Write your data to file system here...
}
}
- (void)deleteFile:(NSString *)fileName {
NSString *filePath = [self documentsFilePath:fileName];
if ([[NSFileManager defaultManager] fileExistsAtPath:filePath]) {
NSError *deleteErr = nil;
[[NSFileManager defaultManager] removeItemAtPath:filePath error:&deleteErr];
if (deleteErr) {
NSLog(#"Can't delete %#: %#", filePath, deleteErr);
}
}
}
Please handle nil checks and store only filename in DB
No, it's not constant. Whenever your app reinstall or updated on device the document directory will change, because when app installed on device os made an directory for app with some random id and each install this random it get changed by OS.
So, you need to make it dynamic own your own, like store the file name only and append the document directory path while using it.
I would suggest only saving the filename or subdirectory/filename (if you have a subdirectory) in the database and then only attaching that to the NSDocumentDirectory.
This will ensure that you always know where the file is...
NSDocumentDirectory is however consistent accross updates, so the files should remain in the document directory even if you update...
I am learning iOS via Standford CS193P, I met a problem in core data part.
I am trying to build an app using core data, I create a category for the AppDelegate(I will create a UIManagedDocument in didFinishLaunchingWithOptions), this category implement one method to create a UIManagedDocument and return it to the AppDelegate, so that I can call self.managedDocument = [self createUIManagedDocument] to get one:
- (UIManagedDocument *)createUIManagedDocument
{
NSFileManager *fileManager = [NSFileManager defaultManager];
NSURL *documentsDirectory = [[fileManager URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] firstObject];
NSURL *url = [documentsDirectory URLByAppendingPathComponent:APP_NAME];
UIManagedDocument *managedDocument = [[UIManagedDocument alloc] initWithFileURL:url];
if ([[NSFileManager defaultManager] fileExistsAtPath:[url path]]) {
// If the file exists, open it
NSLog(#"File exists, not opening...");
[managedDocument openWithCompletionHandler:^(BOOL success) {
NSLog(#"File opened.");
}];
} else {
// If the file not exists, create it
NSLog(#"File not exists, now creating...");
[managedDocument saveToURL:url forSaveOperation:UIDocumentSaveForCreating completionHandler:^(BOOL success) {
// If the file create succesfully, open it
[managedDocument openWithCompletionHandler:^(BOOL success) {
NSLog(#"File opened.");
}];
}];
}
return managedDocument;
}
After the UIManagedDocument creation, I am trying to pass this UIManagedDocument to my view controllers using:
RootViewController *rootViewController = (RootViewController *)self.window.rootViewController;
rootViewController.managedDocument = self.managedDocument;
And the problem occurs, I am unable to open the UIManagedDocument in my view controllers. I searched it for a whole day and got the answer: I was trying to open it twice at the same time while it is asynchronous, it takes time to process the IO request. There are some approaches, and most of them using Singleton.
Here is my question:
Can I do this by using the approach above?
If no, what is the standard(or correct) way to create and pass this UIManagedDocument around my app?
Should I pass NSManagedObjectContext in this UIManagedDocument to my view controllers instead of passing UIManagedDocument?
Thank you for reviewing my question.
In the course, we are told to do this using notifications, he explains this in a demo in lecture 13 at 51:20.
In my game, I'm saving stats of the player in a plist that I store in the Documents directory. I have an empty dictionary of each stats that should be saved named "Default_Stats.plist" so that if it's the first time the app is loaded, it will copy it in the appropriate directory so it could be loaded and overwritten at will. The problem is, every time my app is loaded, it doesn't recognize the "Stats.plist" and overwrite it with the Default Stats, resetting every stats the player have made... And weird enough, it was perfectly working on the simulator, but not on the device. Here's my code :
In this method I read the stats :
- (void) readStatsFromFile{
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *statsPath = [[paths objectAtIndex:0] stringByAppendingPathComponent:#"Stats.plist"];
//Check if the file has already been created
if (![[NSFileManager defaultManager] fileExistsAtPath:statsPath]){
[self createStatsList];
}else{
stats = [[NSMutableDictionary dictionaryWithContentsOfFile:statsPath]retain];
}
}
Here's my creating method :
- (void) createStatsList{
NSString *statsPath = [[NSBundle mainBundle] bundlePath];
statsPath = [statsPath stringByAppendingPathComponent:#"Default_Stats.plist"];
stats = [[NSMutableDictionary dictionaryWithContentsOfFile:statsPath] retain];
[self writeStatsToFile];
}
And my writing method :
- (void) writeStatsToFile{
BOOL ok;
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *statsPath = [[paths objectAtIndex:0] stringByAppendingPathComponent:#"Stats.plist"];
ok = [stats writeToFile:statsPath atomically:YES];
if (!ok) {
NSLog(#"Couldn't write to file");
}else
NSLog(#"Stats written succesfully!");
}
Please help, I really don't understand what's wrong! I hope I've made myself clear enough!
Use filepath instead of absolute path.
Maybe duplicates exist in your mac, which makes exists=true on simulator, but not on device.
The easiest way to check would be to NSLog the paths encountered. Refer to these tools - they allow console logs to be captured for release builds running on your device.
Most likely that your documents directory just doesn't exist - on the simulator you share a documents directory with everyone on the Mac; on the device everyone has his own directory. Use the file manager method
createDirectoryAtURL:url withIntermediateDirectories:YES
to make sure that the directory is there before you try writing there. (I tend to use the URL methods instead of the file path methods).
PS. I'd recommend having one method that returns the path or url that you want. It's a good habit not to duplicate your code again and again.
I would do pretty much that, like everything in one session:
gets the URL for the file in the Document folder;
if the file is not there yet, copies the file from bundle to the Documents folder;
that should be the method for that, I have defined some macros for avoiding mistyping the file's name in the code:
- (NSURL *)statsFileURL {
#define NSStringFromFileNameWithExtension(filename, extension) [(filename) stringByAppendingPathExtension:(extension)]
#define kExtension #"plist"
#define kDefaultStatsFileName #"Default_Stats"
#define kCustomStatsFileName #"Stats"
NSURL *_returnURL = nil;
NSFileManager *_fileManager = [NSFileManager defaultManager];
NSURL *_documentDirectory = [[_fileManager URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
NSURL *_myFileURLInDocumentFolder = [_documentDirectory URLByAppendingPathComponent:NSStringFromFileNameWithExtension(kDefaultStatsFileName, kExtension)];
if ([_fileManager fileExistsAtPath:[_myFileURLInDocumentFolder path]]) {
_returnURL = _myFileURLInDocumentFolder;
} else {
NSURL *_myFileURLInBundle = [[NSBundle mainBundle] URLForResource:kDefaultStatsFileName withExtension:kExtension];
if ([_fileManager fileExistsAtPath:[_myFileURLInBundle path]]) {
NSError *_error = nil;
if ([_fileManager copyItemAtURL:_myFileURLInBundle toURL:_myFileURLInDocumentFolder error:&_error]) {
if (_error == nil) {
_returnURL = _myFileURLInDocumentFolder;
} else {
// some error during copying
}
} else {
// some error during copying
}
} else {
// the file does not esixts at all, not even in the bundle
}
}
return _returnURL;
}
the URL always points inside the Documents folder, so you will have read/write access to the file – or will be nil if some error happens.
after you have the URL, you can restore back to file without any issue, and at some other point in runtime you can override the file for your convenience anytime.
NOTE: you may need to extend this code for a more detailed error handling, I put the comment only the places when you need to worry about potential errors.
I'm trying to copy a downloaded file to a specific folder in the app's documents directory but can't seem to get it working. The code I'm using is:
NSString *itemPathString = #"http://pathToFolder/folder/myFile.doc";
NSURL *myUrl = [NSURL URLWithString:itemPathString];
NSArray *paths = [fm URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask];
NSURL *folderPath = [[paths objectAtIndex:0] URLByAppendingPathComponent:#"folder"];
NSURL *itemURL = [documentsPath URLByAppendingPathComponent:#"myFile.doc"];
// copy to documents directory asynchronously
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
NSFileManager *theFM = [[NSFileManager alloc] init];
NSError *error;
[theFM copyItemAtURL:myUrl toURL:itemURL error:&error];
}
});
I can retrieve the file OK but can't copy it. Can anyone tell me if there's anything wrong with the above code?
If downloading a file from a server, if it's a reasonably small file (e.g. measured in kb, not mb), you can use dataWithContentsOfURL. You can use that method to load the file into memory, and then use the NSData instance method writeToFile to save the file.
But, if it's a larger file, you will want to use NSURLConnection, which doesn't try to hold the whole file in memory, but rather writes it to the file system when appropriate. The trick here, though, is if you want to download multiple files, you either have to download them sequentially, or encapsulate the NSURLConnection and the NSOutputStream such that you can have separate copies of those for each simultaneous download.
I have uploaded a project, Download Manager that demonstrates what a NSURLConnection implementation might look like, but it's non-trivial. You might rather want to contemplate using an established, third-party library, such as ASIHTTPRequest or RestKit.
If you want to access a folder with a given name you should check if it exists and if not create it. That could quite easy be done like this:
NSString *folder = [documentsPath stringByAppendingPathComponent:folderName];
NSFileManager *fileManager = [NSFileManager defaultManager];
NSError *error = nil;
if (![fileManager fileExistsAtPath:folder]) {
[fileManager createDirectoryAtPath:folder withIntermediateDirectories:YES attributes:nil error:&error];
}
if (error != nil) {
NSLog(#"Some error: %#", error);
return;
}
EDIT
If you want to check if the folder was created properly on your device got to Organizer -> Devices -> [YourDevelopingDeviceWhereTheAppWasInstalled] -> Applications -> [YourApplication]
In the lower section you should at least see some folders like Documents. And if successful your created folders as well.
You need to create any intermediate directories prior to copying files. Check in the Simulator folder to see wether the "folder" directory is created in the applications Documents-folder.
Path to simulator is /Users/$username/Library/Application Support/iPhone Simulator/
I have a weird problem. My app works fine on my device but the sqlite database does not work on the simulator. The file "database.sqlite" exists in the same folder as my apps, it has the same name and the columns names are also correct.
So I assume there is something wrong with the configuration but I don't know what. Can someone please help me out.
Thanks
Here are some posts that seem to address the problem : http://forums.macrumors.com/showthread.php?t=484899
One reason might be because you should ensure the database is copied from your Supporting Files application directory (read only) to library or documents before you use it. Here's an ensurePrepared function from a sample of mine that uses sqlite that does just that. In this case, it's called contacts.db
- (BOOL)ensureDatabasePrepared: (NSError **)error
{
// already prepared
if ((_dbPath != nil) &&
([[NSFileManager defaultManager] fileExistsAtPath:_dbPath]))
{
return YES;
}
// db in main bundle - cant edit. copy to library if !exist
NSString *dbTemplatePath = [[NSBundle mainBundle] pathForResource:#"contacts" ofType:#"db"];
NSLog(#"%#", dbTemplatePath);
NSString *libraryPath = [NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES) lastObject];
_dbPath = [libraryPath stringByAppendingPathComponent:#"contacts.db"];
NSLog(#"dbPath: %#", _dbPath);
// copy db from template to library
if (![[NSFileManager defaultManager] fileExistsAtPath:_dbPath])
{
NSLog(#"db not exists");
NSError *error = nil;
if (![[NSFileManager defaultManager] copyItemAtPath:dbTemplatePath toPath:_dbPath error:&error])
{
return NO;
}
NSLog(#"copied");
}
return YES;
}