I was wondering if property lists, (.plist) would save the contents if i were to exit the app and then re-open it. I would like to save a couple of variables to a plist so I could read from it every time I need some universal information about the user in my app.
Do plists save the variables if I were to close and reopen the app?
Should I be using plists or is there a better way to do this?
Thank you!
Yes, you can use plist to save user infomation. This is a sample way. Make a plist and write to the sandbox.
NSString *urlStr = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES).firstObject;
urlStr = [urlStr stringByAppendingPathComponent:#"userInfo.dic"];
NSURL *url = [NSURL fileURLWithPath:urlStr];
[userInfoDictionary writeToURL:url error:NULL];
You can also use SQLite database or Core Data if the information is complex.
Related
I save some run-time generated files inside the .app bundle of my iOS app. In the simulator it works fine, in the device it crashes:
Could create output files in the given shader cache path
'/var/mobile/Applications/CB064997-B40E-4FE3-9834-B3217CE33489/SimedTest.app/Ogre3D/assets/RTShaderLib/cache/
Is there a good overview of where I should and shouldn't put files - how to use Documents, Library and tmp, etc?
To clarify, these are files created at startup which pre-calculate some data to save time. IF they are not present they get created so it's fine they are deleted, but not while the app is running.
The bundle is read-only. You don't want to mess around with it for two reasons:
Code Signing: the signature is verified by against the contents of the bundle; if you mess around with the bundle, you break the signature.
App Updates: updates work by replacing the entire app bundle with a newly downloaded one; any changes you make will get lost.
Where you should save stuff:
Documents: if you want it to persist and be backed up
Library/Caches: if you just want to cache downloaded data, like profile pics; will be auto deleted by the system if it is low on room unless you specify with a special do-not-delete flag.
tmp: temporary files, deleted when your app is not running
For a full explanation check out File System Programming Guide and QA1719.
No, every time you change your bundle you invalidate your signature.
If you want to write files you`l need to write in the best folder depending on what you want to do with that file.
Documents folder for long duration files
Cache for small operations
and so on
EDIT
To get the path you`ll need something like this:
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *path = [documentsDirectory stringByAppendingPathComponent:#"filename.ext"];
With this path you can write or read like this:
write:
NSString *content = #"One\nTwo\nThree\nFour\nFive";
[content writeToFile:fileName atomically:NO encoding:NSStringEncodingConversionAllowLossy error:nil];
read:
NSString *content = [[NSString alloc] initWithContentsOfFile:fileName usedEncoding:nil error:nil];
Here is the NSURL object that I am using for creating and accessing important configuration file on iOS with features:
hidden from user
not user generated file (storing configuration related to user)
not temp or cache (not possible to create later with existing data)
must be backed up by iCloud/iTunes
[NSURL fileURLWithPath:[[NSSearchPathForDirectoriesInDomains(
NSLibraryDirectory,
NSUserDomainMask,
YES) objectAtIndex:0]
stringByAppendingString:#"/important.txt"]];
As suggested in FileSystemOverview (developer.apple.com), I am storing this file under Library.
Maybe better way is storing it under Library/Application Support.
Using NSSearchPathForDirectoriesInDomains, which takes:
enum NSSearchPathDirectory
NSApplicationDirectory
NSDeveloperApplicationDirectory
NSLibraryDirectory
NSDeveloperDirectory
NSApplicationSupportDirectory
...
enum NSSearchPathDomainMask
NSUserDomainMask
NSLocalDomainMask
NSSystemDomainMask
...
BOOL expandTilde
Is this the correct way of storing such a file?
There are couple of alternatives for NSSearchPathDirectory and NSSearchPathDomainMask.
Also what about the expandTilde, on iOS is it necessary?
Is there a better way of doing it, instead of creating path as a NSString using objectAtIndex and appending file name then converting it to NSURL?
Thanks.
Using NSApplicationSupportDirectory would be my first choice for this.
But keep a few things in mind:
Unlike the "Documents" folder, the "Library/Application Support" folder doesn't exist in an iOS app sandbox by default so you must create the folder before trying to use it.
"Hidden from the user" only means that the user won't see it under normal circumstances. But the file is easily accessible by anyone with any technical knowledge.
You do want to pass YES for the expandTilde parameter so your app returns a proper path when you run the app in the simulator. On a real iOS device, it makes little difference.
Do not use stringByAppendingString: to create paths. Use stringByAppendingPathComponent:.
NSString *appSupportPath = [NSSearchPathForDirectoriesInDomains(NSApplicationSupportDirectory, NSUserDomainMask, YES) firstObject];
NSString *filePath = [appSupportPath stringByAppendingPathComponent:#"important.txt"];
NSURL *fileURL = [NSURL fileURLWithPath:filePath];
You can get a direct NSURL using NSFileManager:
NSURL *appSupportURL = [[[NSFileManager defaultManager] URLsForDirectory:NSApplicationSupportDirectory inDomains:NSUserDomainMask] firstObject];
NSURL *fileURL = [appSupportURL URLByAppendingPathComponent:#"important.txt"];
I am trying to update my app for WatchKit and I save a NSKeyedArchiver file to the NSDocumentsDirectory normally.
With updating to app groups I need to store it in the app groups folder. The issue I am having is I cant figure out how to just get the path, and not have it referenced as a file I am looking for.
The way it is set up now is to find the file it gives the path as a NSString
/Users/ME/Library/Developer/CoreSimulator/Devices/43F/data/Containers/Data/Application/5E/Documents/fav
but when I store to app groups, no matter which way I access the folder, it is returned
file:///Users/ME/Library/Developer/CoreSimulator/Devices/43F/data/Containers/Data/Application/5E/Documents/fav
What is the best way to just obtain the path to the shared group, rather than have the app looking for the direct file?
So coffee deprived me had forgotten about the .path for filemanager.
NSURL *fileManagerURL = [[NSFileManager defaultManager] containerURLForSecurityApplicationGroupIdentifier:#"group.com"];
NSString *tmpPath = [NSString stringWithFormat:#"%#", fileManagerURL.path];
NSString *finalPath = [NSString stringWithFormat:#"%#",[string stringByAppendingString:#"/Favourites2"]];
I was running into the same problem. I was going through the whole process of building a string to my save location and now I'm switching over to app groups and using the
NSURL *fileManagerURL = [[NSFileManager defaultManager] containerURLForSecurityApplicationGroupIdentifier:groupID];
Well, the problem is, now instead of a string to the location that starts with "/Users/yourname/Library..." you get "file:///Users/yourname/Library..."
Here's what I did. I created the NSURL. Then I called absoluteString on it.
NSURL groupPath = [[fileManager containerURLForSecurityApplicationGroupIdentifier:groupID] absoluteString];
I now have a string that I need to strip off the first 7 characters of, then my old code works just fine, except now instead of being in the Documents directory, it's in a shared app group that can be accessed by both my old code and my new watchkit extension.
Here's the code to strip off the first 7 characters (index 6 since you start with 0), you should be able to use either method...
NSString *newGroupPath = [groupPath substringFromIndex:6];
or
NSString *newGroupPath = [groupPath substringWithRange:NSMakeRange(6, [str length]-6)];
This just removes the "file://" from the absoluteString that was made from the NSURL and gives you back your older string path the starts "/Users/YourName/Library/Developer/yada yada yada"
Hope that helps you, I have spent 4 hours figuring it out.
It seems to work for me on the simulator, I haven't tried it on the Watch yet. But at least my app is now working the way it was before, just saving the data in a shared app group. (I have a singleton that manages all of my data throughout my app, and I want that same singleton to provide data to my watch app).
I save some run-time generated files inside the .app bundle of my iOS app. In the simulator it works fine, in the device it crashes:
Could create output files in the given shader cache path
'/var/mobile/Applications/CB064997-B40E-4FE3-9834-B3217CE33489/SimedTest.app/Ogre3D/assets/RTShaderLib/cache/
Is there a good overview of where I should and shouldn't put files - how to use Documents, Library and tmp, etc?
To clarify, these are files created at startup which pre-calculate some data to save time. IF they are not present they get created so it's fine they are deleted, but not while the app is running.
The bundle is read-only. You don't want to mess around with it for two reasons:
Code Signing: the signature is verified by against the contents of the bundle; if you mess around with the bundle, you break the signature.
App Updates: updates work by replacing the entire app bundle with a newly downloaded one; any changes you make will get lost.
Where you should save stuff:
Documents: if you want it to persist and be backed up
Library/Caches: if you just want to cache downloaded data, like profile pics; will be auto deleted by the system if it is low on room unless you specify with a special do-not-delete flag.
tmp: temporary files, deleted when your app is not running
For a full explanation check out File System Programming Guide and QA1719.
No, every time you change your bundle you invalidate your signature.
If you want to write files you`l need to write in the best folder depending on what you want to do with that file.
Documents folder for long duration files
Cache for small operations
and so on
EDIT
To get the path you`ll need something like this:
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *path = [documentsDirectory stringByAppendingPathComponent:#"filename.ext"];
With this path you can write or read like this:
write:
NSString *content = #"One\nTwo\nThree\nFour\nFive";
[content writeToFile:fileName atomically:NO encoding:NSStringEncodingConversionAllowLossy error:nil];
read:
NSString *content = [[NSString alloc] initWithContentsOfFile:fileName usedEncoding:nil error:nil];
I want to handle files in my iOS App.
My app should create a file with a custom suffix (e.g. file.mysuff) and save it to the device so I'll be able to copy it using iTunes File Sharing.
Then I want to be able to attach that file to a new mail.
When the receiver opens the document, mail should launch my app and handle that file.
Are there good tutorials on that topic?
I'm still quite new to cocoa / cocoa touch so it should be easy to my.
Is maybe a wrapper out there that I could implement so I just have to code something like
[self [saveMyFile path:[NSURL] contents:[NSString]]]??
Thanks for help!
Greets, J.
This is one example of how you can save the file to documents on the iPhone to use later. This stores a dictionary from a list, changes a value and then writes the updates dictionary back to the file specified. Let me know if this is what you were looking for.
//user document directory and instantiate dictionary
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectoryPath = [paths objectAtIndex:0];
NSString *plistFilePathInDocumentsDirectory = [documentsDirectoryPath stringByAppendingPathComponent:#"YourFile"];
NSMutableDictionary *yourList= [[NSMutableDictionary alloc] initWithContentsOfFile:plistFilePathInDocumentsDirectory];
//save the new information to the plist in the user documents directory
[yourList setObject:someObject forKey:someKey];
[yourList writeToFile:plistFilePathInDocumentsDirectory atomically:YES];