My app uses iTunes File Share. I used the code to delete a single file:
It worked the first time. On the second try, however, iTunes showed a empty share directory. It turns out all data files are gone. Can I recover those data files from the iPad? Thanks
- (void) deleteFileFromDisk: (NSString*) fileName {
if([self fileExists: fileName]) {
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) ;
NSString *documentsDirectory = [paths objectAtIndex: 0];
NSString* theFile = [documentsDirectory stringByAppendingPathComponent: fileName];
NSError *error;
[[NSFileManager defaultManager] removeItemAtPath: theFile error: &error];
There's no "restore" feature on the iPad. But in all probability there's nothing to worry about.
There's nothing about your code that would delete multiple files. It would delete just that file from the Documents directory that you supplied the name of as fileName. If you didn't call deleteFileFromDisk: multiple times, you didn't delete multiple files.
Perhaps at some point you deleted the app. That would delete its entire sandbox and thus would take with it anything in the Documents directory. That sort of thing is perfectly normal during repeated testing.
Related
I am trying to take content from one file and write it into another. I am reading fine, but I am not able to write it into another file.
I have a database of words. I want to separate the words into different files based on the number of letters. All four letter words go into one file, and so on. I added a txt file called "4letter" into my resources and the following is my code:
NSError *error;
//READ
NSString *dbFile = [[NSBundle mainBundle] pathForResource:#"words" ofType:#"txt"];
NSString *test = [NSString stringWithContentsOfFile:dbFile encoding:NSUTF8StringEncoding error:&error];
//convert from string to array
NSArray *lines = [test componentsSeparatedByString:#"\n"];
NSFileHandle *logFile = nil;
logFile = [NSFileHandle fileHandleForWritingAtPath:[[NSBundle mainBundle] pathForResource:#"4letter" ofType:#"txt"]];
//Test if write works
for (int i=0; i<5; i++)
{
NSString *randomAnagram = [[lines objectAtIndex:i] lowercaseString];
[logFile writeData: [randomAnagram dataUsingEncoding: NSNEXTSTEPStringEncoding]];
}
In iOS, you can't write into a file in your app's bundle -- the entire bundle is read-only. Use a path into the Documents folder instead.
See special File System Programming Guide for better understnading.
In iOS, you can't write into a file in your app's bundle -- the entire bundle is read-only.
Consider reading iOS Data Storage Guidelines to better understand the purpose of directories below, in context of iCloud backup.
<Application_Home>/AppName.app
This is the bundle directory containing the app itself. Do not write
anything to this directory. To prevent tampering, the bundle directory
is signed at installation time. Writing to this directory changes the
signature and prevents your app from launching again.
<Application_Home>/Documents/
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. The contents of this directory can be
made available to the user through file sharing. The contents of this
directory are backed up by iTunes.
<Application_Home>/Library/
This directory is the top-level directory for files that are not user
data files. You typically put files in one of several standard
subdirectories but you can also create custom subdirectories for files
you want backed up but not exposed to the user. You should not use
this directory for user data files. The contents of this directory
(with the exception of the Caches subdirectory) are backed up by
iTunes. For additional information about the Library directory, see
“The Library Directory Stores App-Specific Files.”
See full list (tmp/, Documents/Inbox) in iOS Standard Directories: Where Files Reside
UPDATE
I use NSFileManager method URLForDirectory:inDomain:appropriateForURL:create:error:
Like Caleb said, you can't write to your app's directory, but you can write to your app's Documents folder. You can get it like this:
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
Your app's bundle is read-only. There is two ways I could see:
1) Write in documents folder:
NSArray *pathList = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *path = [myPathList objectAtIndex:0];
2) Use sqlite database. This is the same as 1 (you must save db in documents anyway), but you're using sqlite database. I think this is better than a lot of txt and plist files: here's a tutorial on the topic.
I use the following code :
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *appFile = [documentsDirectory stringByAppendingPathComponent:#"set.txt"];
NSString *data=#"Kostas";
[data writeToFile:appFile atomically:YES];
NSString *myData = [NSString stringWithContentsOfFile:appFile];
NSLog(#"Data : %# ",myData);
I am trying to take content from one file and write it into another. I am reading fine, but I am not able to write it into another file.
I have a database of words. I want to separate the words into different files based on the number of letters. All four letter words go into one file, and so on. I added a txt file called "4letter" into my resources and the following is my code:
NSError *error;
//READ
NSString *dbFile = [[NSBundle mainBundle] pathForResource:#"words" ofType:#"txt"];
NSString *test = [NSString stringWithContentsOfFile:dbFile encoding:NSUTF8StringEncoding error:&error];
//convert from string to array
NSArray *lines = [test componentsSeparatedByString:#"\n"];
NSFileHandle *logFile = nil;
logFile = [NSFileHandle fileHandleForWritingAtPath:[[NSBundle mainBundle] pathForResource:#"4letter" ofType:#"txt"]];
//Test if write works
for (int i=0; i<5; i++)
{
NSString *randomAnagram = [[lines objectAtIndex:i] lowercaseString];
[logFile writeData: [randomAnagram dataUsingEncoding: NSNEXTSTEPStringEncoding]];
}
In iOS, you can't write into a file in your app's bundle -- the entire bundle is read-only. Use a path into the Documents folder instead.
See special File System Programming Guide for better understnading.
In iOS, you can't write into a file in your app's bundle -- the entire bundle is read-only.
Consider reading iOS Data Storage Guidelines to better understand the purpose of directories below, in context of iCloud backup.
<Application_Home>/AppName.app
This is the bundle directory containing the app itself. Do not write
anything to this directory. To prevent tampering, the bundle directory
is signed at installation time. Writing to this directory changes the
signature and prevents your app from launching again.
<Application_Home>/Documents/
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. The contents of this directory can be
made available to the user through file sharing. The contents of this
directory are backed up by iTunes.
<Application_Home>/Library/
This directory is the top-level directory for files that are not user
data files. You typically put files in one of several standard
subdirectories but you can also create custom subdirectories for files
you want backed up but not exposed to the user. You should not use
this directory for user data files. The contents of this directory
(with the exception of the Caches subdirectory) are backed up by
iTunes. For additional information about the Library directory, see
“The Library Directory Stores App-Specific Files.”
See full list (tmp/, Documents/Inbox) in iOS Standard Directories: Where Files Reside
UPDATE
I use NSFileManager method URLForDirectory:inDomain:appropriateForURL:create:error:
Like Caleb said, you can't write to your app's directory, but you can write to your app's Documents folder. You can get it like this:
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
Your app's bundle is read-only. There is two ways I could see:
1) Write in documents folder:
NSArray *pathList = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *path = [myPathList objectAtIndex:0];
2) Use sqlite database. This is the same as 1 (you must save db in documents anyway), but you're using sqlite database. I think this is better than a lot of txt and plist files: here's a tutorial on the topic.
I use the following code :
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *appFile = [documentsDirectory stringByAppendingPathComponent:#"set.txt"];
NSString *data=#"Kostas";
[data writeToFile:appFile atomically:YES];
NSString *myData = [NSString stringWithContentsOfFile:appFile];
NSLog(#"Data : %# ",myData);
I'm trying to create a folder in my documents directory and I want to be able to do it without typing out /Users/(username)/Documents/Foo/Bar
NSString *directoryPath = [NSString stringWithFormat:#"%#/Documents/Foo/Bar", NSHomeDirectory()];
BOOL isDir;
NSFileManager *fileManager= [NSFileManager defaultManager];
if(![fileManager fileExistsAtPath:directoryPath isDirectory:&isDir])
if(![fileManager createDirectoryAtPath:directoryPath withIntermediateDirectories:YES attributes:nil error:NULL])
NSLog(#"Error: Create folder failed %#", directoryPath);
This doesn't work when I try using NSHomeDirectory() with it. But if I typed out the full path /Users/(username)/Documents/Foo/Ba it works. How can it be done to not have to know the users folder?
EDIT:
directoryPath becomes
/Users/(username)/Library/Developer/CoreSimulator/Devices/FAB78255-38D2-49BE-9683-7A0676EA2288/data/Containers/Data/Application/67B0AACE-572A-4808-9535-D221AEEB9EFA/Foo/Bar
I just want /Users/(username)
This is an iOS app. The "Documents" folder of an iOS app's sandbox is not at all related to the user's "Documents" folder on their computer.
Since you appear to be running your iOS in the simulator, the path you are getting is more like what you should be seeing. You do not want a path in the user's home directory.
Keep in mind that you can't get access to the "Documents" folder of an iOS app using NSHomeDirectory(). That may have worked in older versions of iOS but it fails in iOS 8 and later. The proper code needs to be something like this:
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsFolder = paths[0];
NSString *directoryPath = [documentsFolder stringByAppendingPathComponent:#"Foo/Bar"];
I am using NSKeyedArchiver and NSKeyedUnarchiver to implement cache function for my app.
In order to load the cache file each time the app launches, I store the cache file under NSHomeDirectory(). The code (C function) is as following:
NSString* getArchivePathForId(NSString* modelId)
{
NSString *cacheIdentifier = #"CacheIdentifier";
NSString *archiveDirPath = [NSHomeDirectory() stringByAppendingFormat:#"/tmp/%#/cachedModel/%#", getAppVersion(), cacheIdentifier];
NSError* error;
if (![[NSFileManager defaultManager] fileExistsAtPath:archiveDirPath]) {
if (![[NSFileManager defaultManager] createDirectoryAtPath:archiveDirPath
withIntermediateDirectories:YES
attributes:nil
error:&error])
{
NSLog(#"Create directory tmp/cachedModel directory error: %#", error);
return nil;
}
}
NSString *archivePath = [archiveDirPath stringByAppendingFormat:#"/%#", modelId];
return archivePath;
}
It works fine as long as the App is running or coming back to live from the background mode. But once the app is terminated and re-run, the cached archive file is deleted.
Is there any way to persist the archive file so that I can load the cache stored last time when the app was launched.
I have already realised that each time the app is launched, the application id part of the NSHomeDirectory() is different. Does this have anything to do with my issue?
The issue is the "tmp" directory name at the top level. Generally files are saved under the "Documents" directory:
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths firstObject];`
Persistent caches are generally placed under the "Library" directly, use NSLibraryDirectory.
See: File System Programming Guide
tmp/
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 they are no longer needed; however, the system may purge this directory when your app is not running.
I'm using this code to read data from a local (in the XCode project) .plist file.
NSError *error;
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *path = [documentsDirectory stringByAppendingPathComponent:#"GameData.plist"];
NSFileManager *fileManager = [NSFileManager defaultManager];
if (![fileManager fileExistsAtPath: path])
{
NSString *bundle = [[NSBundle mainBundle] pathForResource:#"GameData" ofType:#"plist"];
[fileManager copyItemAtPath:bundle toPath: path error:&error];
}
gameData = [[NSMutableDictionary alloc] initWithContentsOfFile: path];
And it worked great the start, but now I find when I step through the code in the simulator that my game is using a version of the .plist file that existed right at the start, and the new fields I've set up in my new GameData.plist file is not appearing.
I presume that's because it doesn't get the data again if the file already exists? but then how do I get the new version of the .plist file? I tried removing the if statement, but I get a runtime error saying the file already exists.
It sounds like you need to setup a version system. But, the only reason to copy a file from the bundle to the documents folder is so you can edit it, so you need to think about how to merge the updated file in the bundle and the users additions in the documents folder.
Once you have a plan for merging the files, then you can change your if statement so it doesn't just check if the file already exists (if it does, you need to delete it before you can replace it) but also considers the version. You may want to store the currently copied version number in user defaults and add a version number to the file in the bundle. You may also want to keep the user modified data in a different file and use that as overrides.