I am using the symbolic link with iPhoneApp.
NSString* js_path = [[NSBundle mainBundle] pathForResource:#"js" ofType:nil];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
if (js_path != nil) {
NSFileManager *fm = [NSFileManager defaultManager];
NSString* move_js_path = [NSString stringWithFormat:#"%#/js", [paths objectAtIndex:0]];
NSError *error;
if ([fm createSymbolicLinkAtPath:move_js_path withDestinationPath:js_path error:&error]) {
} else {}
}
I updated the application program. It becomes impossible to read the file afterwards.
However, the file was able to be read by reinstalling it after the application program had been deleted once.
Is there a problem in this code?
If anyones wondering about this, the reason is the application moves directory every time it's updated, the solution might be to use relative paths bundles are located at /var/mobile/Applications/[unique id that changes every update]/app.app whereas the documents directory is located at /var/mobile/Applications/[unique id that changes every update]/Documents so a symlink from Documents to the bundle will always work if it uses something like ../[bundlepath lastPathComponent]/Documents
ofc it's a good idea to build the relativeness from the directories you get at runtime rather than hard coding it, incase these relative paths change in the future.
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...
So, my app queries an Amazon Dynamo DB database and retrieves a few kilobytes worth of data. What I want the app to do is download everything the first time, and then every time after, just download a timestamp to see if it has the most recent version of the data. So that I only have to download the data every once in a while, I'm trying to use NSKeyedArchiver to archive the array that I'm downloading. I have tried this three different ways, and none of them work on an iPhone, although two of them work on the simulator.
[NSKeyedArchiver archiveRootObject:self.dataArray toFile:#"dataArray.archive"];
This does not work on the simulator nor the actual iphone. The result of this method is NO.
The next thing I used was the full path:
[NSKeyedArchiver archiveRootObject:self.dataArray toFile:#"Users/Corey/Desktop/.../dataArray.archive"];
And this worked on the simulator, but not on the iPhone. My guess was that when compiled, the filesystem looks different (and obviously doesn't have the same path). So next I tried:
NSString *filePath = [[NSBundle mainBundle] pathForResource:#"dataArray" ofType:#".archive"];
[NSKeyedArchiver archiveRootObject:self.dataArray toFile:filePath];
Once again, this works on the simulator but fails on the iphone. I have confirmed that all of the data is in self.dataArray before writing to the archive, and confirmed that the array is nil after writing back to the archive (in the iphone version). Any ideas what's going on? Is there a better way to do the filepath?
This is what I tracked down:
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *filePath = [documentsDirectory stringByAppendingPathComponent: #"dataArray.archive"];
[NSKeyedArchiver archiveRootObject:your_object toFile:filePath];
and it worked perfectly on both the simulator and the iPhone!
[NSKeyedArchiver archiveRootObject:self.dataArray toFile:#"dataArray.archive"];
You have to provide a full path.
[NSKeyedArchiver archiveRootObject:self.dataArray toFile:#"Users/Corey/Desktop/.../dataArray.archive"];
That is not a full path. A full path begins with / and does not have /../ anywhere.
NSString *filePath = [[NSBundle mainBundle] pathForResource:#"dataArray" ofType:#".archive"];
You do not have permission to write inside the mainBundle, it is read only.
Also, in general you shouldn't use file paths, you should use URLs. Some APIs (including this one) requires a path but URLs are the recommended approach these days.
Here's the proper way to write the file to disk:
NSURL *applicationSupportUrl = [[NSFileManager defaultManager] URLsForDirectory:NSApplicationSupportDirectory inDomains:NSUserDomainMask][0];
applicationSupportUrl = [applicationSupportUrl URLByAppendingPathComponent:#"My App"]; // replace with your app name
if (![applicationSupportUrl checkResourceIsReachableAndReturnError:NULL]) {
[[NSFileManager defaultManager] createDirectoryAtURL:applicationSupportUrl withIntermediateDirectories:YES attributes:#{} error:NULL];
}
NSURL *archiveUrl = [applicationSupportUrl URLByAppendingPathComponent:#"foo.archive"];
[NSKeyedArchiver archiveRootObject:self.dataArray toFile:archiveUrl.path];
NSFileManager *fileMgr = [[NSFileManager alloc] init];
NSError *error = nil;
NSString *cachePath = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSArray *files = [fileMgr contentsOfDirectoryAtPath:cachePath error:nil];
for (NSString *path in files)
{
NSString *fullPath = [cachePath stringByAppendingPathComponent:path];
BOOL removeSuccess = [fileMgr removeItemAtPath:fullPath error:&error];
if (!removeSuccess)
{
return error;
}
}
the code above occasionally gives cocoa error 513 which is about permissions. I download files from internet placing in caches directory. Do I have to explicitly set some permissions or do something else? Why the error happens only sometimes? It never happens on 6.0/7.0, but happens sometimes on 7.1.
As I write in comment I guess the problem related to deleting some system files that not directly own by your app and should not be deleted.
for example how looks Cache folder in basic app with one UIWebView
To avoid strange errors is better to create dedicated folder inside Library/Caches and delete content inside respected to your needs
I have a bunch of images stored in an images directory within my Supported Files directory in Xcode. I want to be able to show one of those images. What is the best way to obtain a path to that image? Do I have to copy them to the Documents directory first? If so, how can I do that?
EDIT: I've tried the following to copy the image from Supporting Files to the Documents folder in the app. It successfully copies, but I can't get the image to show:
-(void)findImage:(NSString *)imageName
{
// First, test for existence.
BOOL success;
NSFileManager *fileManager = [NSFileManager defaultManager];
NSError *error;
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *appImagePath = [documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:#"%#.jpg",imageName]];
success = [fileManager fileExistsAtPath:appImagePath];
if (success)
{
return;
}
// The writable database does not exist, so copy the default to the appropriate location.
NSString *defaultImagePath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:[NSString stringWithFormat:#"%#.jpg",imageName]];
success = [fileManager copyItemAtPath:defaultImagePath toPath:appImagePath error:&error];
if (!success)
{
NSAssert1(0, #"Failed to create writable database file with message '%#'.", [error localizedDescription]);
}
self.imageDisplay.image = [UIImage imageNamed:appImagePath];
return;
}
This should do the trick:
[UIImage imageNamed:#"someImageName"];
EDIT:
Some additional information:
-imageNamed: will look through the entire main bundle of the application for an imagefile (preferrably an png) with the filename of "someImageName". You need not worry about its location or its extension, since it will be searched for in the mainbundle. Files that you import through the import-file-dialogue in xcode will be added to he main bundle.
This means:
If i have imported a file called myImage.png, calling [UIImage imageNamed:#"myImage"];from anywhere in my code will get me a UIImage-Object containing that image. Its amazingly simple, and maybe that startled you a bit ;)
Look it up in the docs if you like:
http://developer.apple.com/library/ios/#documentation/UIKit/Reference/UIImage_Class/Reference/Reference.html
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.