Is there a case when data would be erased (i.e. looking like clean install of app) besides using the Remove App feature?
I know the Downloads folder could be erased automatically if the device runs low on internal storage. What about my app?
Also, is there some kind of magical quota where app data would get deleted?
Related
I am building an iOS app in Xcode 9.4 using CoreData to persist data. As I build the app and test it there is a problem with linking to the data from the previous session (after reboots, etc.) because Xcode changes the location where it stores information.
This is important for the short term because it disrupts the workflow, but more importantly in the long term because I want to be able to preload the basic data set when the app goes to the app store.
I would appreciate some solid guidance on how to solve this problem.
You should not be storing absolute paths to anything.
When the app is installed in the Simulator, if it already exists it is upgraded just like it is on devices. That means your data container may be migrated to a new location on the filesystem. Nothing is deleted between sessions, even if you shut down a specific simulator and start it up again.
Make sure you are using FileManager to search for the documents directory and make all your paths relative to that.
I have Xamarin Forms application. I'm using PCL storage to save image from web. Path to this storage (FileSystem.Current.LocalStorage) is:
"/data/user/0/com.MyApp/files"
On my Android phone, when I go to settings->Application manager->MyApp->Storage->Storage used->Change and put application to SD card, path to LocalStorage doesn't change. It is still:
"/data/user/0/com.MyApp/files"
Why it hasn't changed?
The LocalStorage folder will always remain the same, it's not dynamic or dependant on where your app is running from.
I suspect it is either a naming thing or refers to a similar concept as Microsoft implemented with the local and roaming folders. Local folders are meant to stay on the local device you are running from (but still at a fixed location) and the contents of the roaming folder can be synced across multiple devices or platforms. But this last part is just a guess on my end.
If you want to write to other folders you will have to go beyond PCLStorage and start writing dependency services. See this documentation page for the SpecialFolder enum listing. There is also some useful info on an older forum post on the Xamarin forum.
Edit
Of course we could just see what is going on in the repo code. Here you can see that for Android the LocalStorage folder is the MyDocuments folder on Android. As you have found out for yourself, that will always map to the same folder. If you want to have something on the SD card, you will have to take care of that yourself.
I came across the term "IsolatedStorage" in windows phone. Can anybody explain it in detail how is it related to windows phone applications? Also how does it affect while application version upgrade?
Isolated Storage refers the private read / write directories that each app has for storing their own data. It is isolated from all other apps on the system. When an app is upgraded via the store on an end-user's machine, the isolated storage is preserved.
Note that during development, Isolated Storage of an app can be deleted if you do a full rebuild of the project.
IsolatedStorage is a way of allowing apps to save files locally to the application within a device. Until the app is uninstalled, the IsolatedStorage for the application is persisted. If the user upgrades the app in the store, as long as there isn't a change in the way the IsolatedStorage is implemented, it will also be preserved during the update.
I have an application on Marketplace, the application uses Isolated storage.
I have an update to the app which fixes a few bugs and also adds the facility to connect and sync with my website (which is a cloud based version of the same app).
My question is; what is the risk of the isostore getting wiped or corrupted during the upgrade? Is the protocol to warn users or do we assume that they regularly back up their phones and consider this a non issue?
I believe that isolated storage remains intact (after all, this is why there are dedicated APIs for upgrading database schema in-place) - it's only if an application is uninstalled, does it's isolated storage get wiped as well.
As Rowland said, The Isolated storage wipes off only if the application is uninstalled. If you have changed the way data is written or read from storage in update, make sure the update does not break anything.
Isolated Storage Best Practices for Windows Phone
I bought my own application from the Mac AppStore. The app was not saved in the Applications folder, but instead in /Users/nathan/Library/Developer/Xcode/Archives/2011-06-14/Release PackageTracking 6-14-11 12.09 PM.xcarchive/Products/Users/nathan
Is it just for me because I am the developer? Or are all my users going to have to hunt down that file? Why didn't it download it to the correct location?
You have to find and delete (or hide) absolutely every copy of your application (all debug copies, archive copies, anything with the same bundle ID) from your system before doing a test purchase.
You can try using Spotlight to find apps.
One way to hide apps is to compress them using gzip. Or move them to a disk drive that can be unmounted.
Users with no previous copies of your app won't have this problem. Users who have previous copies of your app and who put these copies in strange places might encounter this problem.
I would hazard a guess that it is because you already had a version of the app in that location from when you built it using the Archive option in Xcode.
The App Store would have detected that it has the same bundle ID and updated it in-place.