Qt and app data storage in Android

Question

I am working on a mobile app, using Qt/C++, right now focusing on Android. My app needs to store some permanent data, in a private and secure way (not accessible to other apps, protected as much as possible):

• some basic key/value settings: QSettings seems to be what I need here. The question being where does this end up in Android, is it stored in the shared preferences section?
• binary files, such as a few pics (these are created by the app, not static resources). I would have stored this in an internal storage file; where would I store this in Qt? Do I use Qt's file capabilities, and java calls to find my app's internal storage folder, or is there a Qt object designed for that?

Thanks.

Answer 1

Android maintains a standard storage for applications under the path /data/user/0 , where each application gets storage space. so if you have an application named org.qtproject.example.myApp, Android automatically creates storage space for this app:

/data/user/0/org.qtproject.example.myApp

The settings are stored under the files folder of this path, as ../files/.config/OrganizationName/AppName.conf

When you want to store information in Android you don't use absolute paths, instead you specify the location of your storage using Qt QStandardPaths which usually returns location under the application path mentioned above, so for example to store a file mySomeFile, you would set the path using QStandardPaths like:

auto path = QStandardPaths::writableLocation(QStandardPaths::AppDataLocation);
auto fileName= path + "/mySomeFile";

and the file is stored as :

/data/user/0/org.qtproject.example.myApp/files/mySomeFile