We have an iOS application for the iphone that is having strange behavior. I store some data of the app in an SQLite Database file in the documents folder. Every once in a while i realize that when the application crashes the file on the disk gets deleted. And i can´t figure out why the app would do this...Any Ideas?!
Make sure that you're saving any documents for the application to the application's private folder in the documents. I use this:
[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainask, YES) lastObject];
Found the Solution...If i save my database in the Cache Directory instead of the Documents directory, it works...:)
Related
I have an app which displays text data with images and or videos which is displayed in a UITableView. I have a requirement now that the data must be available offline. I am thinking of pruge and store data every time I have a connection i.e new data is being downloaded. How can this be achieved - storing the data in a mysql table or any other solution. Please note that I am using AFNetworking to stream the images in uiimageview. The images and videos should be stored as blob is the local mysql database? Please note that my project is not using coredata.
The best way would probably be to download and store the media files in the caches directory.
Then, when you need to access a file, you can check to see if it exists, and if so, use it, and if not, handle that condition in whatever manner you need.
NSFileManager *fileManager = [NSFileManager defaultManager];
NSString *cachePath = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) objectAtIndex:0];
if(![fileManager fileExistsAtPath:[cachePath stringByAppendingPathComponent:#"myfile.zip"]]) {
//create it, copy it from app bundle, download it etc.
}
//start using it
The caches directory is not backed up with the rest of your app, so if you have large files you will not impact the user's backup storage sizes this way.
If you absolutely must have the files in the backup, use the Documents directory instead of the caches directory.
You said you were using AFNetworking, which can stream a download to a file just fine, and even has support for turning the task into a background operation so that it can finish after the app has been closed.
I want to save multipel photos in my application, so that application run in background.
So what is the main difference between saving photos in doc dir or temp path.
And suggest me which is best way to save photos
Document Dir
Temp Folder
NSUserDefaults
Thanks in advance
Here is a reference: File System Programming Guide.
Temp folder:
Use this directory to write temporary files that do not need to
persist between launches of your app. Your app should remove files
from this directory when it determines they are no longer needed. (The
system may also purge lingering files from this directory when your
app is not running.)
Documents folder:
Use this directory to store critical user documents and app data
files. Critical data is any data that cannot be recreated by your app,
such as user-generated content.
Usually, I put files in temporary folder only when I cache something and I don't care if these files will be deleted. If I want to be sure these files should live long life, I put them to documents folder.
The main difference is the path: <sandbox>/Documents or <sandbox>/tmp.
Some more differences:
The Documents directory can be accessed via iTunes if your app has file sharing enabled.
The contents of the tmp directory is volatile, the OS is free to purge it in order to save space.
About NSUserDefaults: that's something completely different, it's a mechanism which stores app-specific configuration data in property lists, I can't imagine how and/or why you would use it for storing images.
To get to my application documents folder, I use this code:
[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
I want to access this folder, however:
~/Library/Mobile Documents
How can i easily access this as a path value? Can I do this in a similar way?
The benefit of using the constants to access system provided directories is that if Apple decide to change the structure, your application will still work. Hardcoding in something like ~/Library/Mobile Documents is brittle.
However, you can access the Library directory with the same NSSearchPathForDirectoriesInDomain with the NSLibraryDirectory constant. Then, you should just append the Mobile Documents directory path.
// Set the NO to YES to get the full path, not the ~ version.
NSString *path = [NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, NO) lastObject];
path = [path stringByAppendingPathComponent:#"Mobile Documents"];
Looking at the constant values in http://developer.apple.com/library/ios/#documentation/Cocoa/Reference/Foundation/Miscellaneous/Foundation_Constants/Reference/reference.html#//apple_ref/doc/c_ref/NSSearchPathDirectory, it appears there is no specific constant for the Mobile Documents directory, so the hardcoding approach might be your only option.
Mobile Documents are iCloud documents. So you want to store documents in iCloud.
On OS X they are definitely in ~/Library/Mobile Documents (10.7 and 10.8), but on iOS you should not look.
"All documents of an application are stored either in the local sandbox or in an iCloud container directory."...
"A user should not be able to select individual documents for storage in iCloud. "
http://developer.apple.com/library/ios/#documentation/DataManagement/Conceptual/DocumentBasedAppPGiOS/ManageDocumentLifeCycle/ManageDocumentLifeCycle.html
So if your user picks iCloud then you should use iCloud.
How long the iCloud document model will last is anyones guess, but that's the way it works today. The whole thing seems a masterpiece of poor UI design, as this direct answer to your question shows:
-(NSURL*)ubiquitousContainerURL {
return [[NSFileManager defaultManager] URLForUbiquityContainerIdentifier:nil];
}
In my recent macOS app I had the same need: how to gain access to the root folder of your iCloud directory.
IMPORTANT!
This is written for an unsandboxed version, since the app is only intended for myself. If you plan to release an app on the Mac App Store, do not turn off sandboxed version.
I turn off sandbox in the app's entitlements file.
This code will access your iCloud root folder:
let pathToiCloudFolder = NSString(string: "com~apple~CloudDocs").expandingTildeInPath
let backUpFolderUrl = FileManager.default.urls(for: .libraryDirectory, in:.userDomainMask).first!
let backupUrl = backUpFolderUrl.appendingPathComponent("Mobile Documents/" + pathToiCloudFolder)
print("Backup Folder:", backupUrl)
I am downloading some mp3 files through my application using NSURLConnection. Actually where can I save the downloaded file. Someone says that saving in to NSDocumentDirectory will lead to app rejection.
Can I save the file to NSCacheDictionary and retrieve this from itunes?
I used this bit of code to save files to NSCacheDictionary
NSString *cachesPath = [NSSearchPathForDirectoriesInDomains(
NSCachesDirectory, NSUserDomainMask, YES)
objectAtIndex: 0];
NSString *documentsDirectoryPath = [cachesPath stringByAppendingPathComponent:#"music.mp3"];
[receivedData writeToFile:documentsDirectoryPath atomically:YES];
Can I use like this?
If you save the files to NSCacheDictionary you will not be able to retrieve them from itunes.
Edit:
You can store the mp3 files to NSDocumentDirectory and set "do not backup" flag
for setting the flag you can check the Technical Q&A QA1719.
For additional information you can check the docs.
specifically:
Use this attribute with data that can be recreated but needs to
persist even in low storage situations for proper functioning of your
app or because customers expect it to be available during offline use.
This attribute works on marked files regardless of what directory they
are in, including the Documents directory.
I have developed one app in which, monthly magazine issues are downloaded and stored inside the app Document directory.
But app have rejected app due to storing of magazine issue in document directory. My magazine file size is around 50 MB.
They mentioned below:
The iOS Data Storage Guidelines indicate that only content that the user creates using your app, e.g., documents, new files, edits, etc., may be stored in the /Documents directory - and backed up by iCloud.
Temporary files used by your app should only be stored in the /tmp directory; please remember to delete the files stored in this location when the user exits the app.
Data that can be recreated but must persist for proper functioning of your app - or because customers expect it to be available for offline use - should be marked with the "do not back up" attribute. For NSURL objects, add the NSURLIsExcludedFromBackupKey attribute to prevent the corresponding file from being backed up. For CFURLRef objects, use the corresponding kCFURLIsExcludedFromBackupKey attribute.
Any help appreciate.
Thanks.
Move your files to the Caches directory and you should be good to go.
I believe that if it is user generated content, there is no problem with storing it on the /Documents folder.
Since it is content that can be downloaded again, you have to set the NSURLIsExcludedFromBackupKey file attribute which prevents it from being backed up to iCloud.
Take a look at this question on setting the attribute: Use NSURLIsExcludedFromBackupKey without crashing on iOS 5.0