Qt Android assets

[KMax]

Hey guys,

I got the following problem:
I'm developing a cross platform application (Linux/Android) and I'm stuck at deploying my SQLite database to Android - it works perfectly well for Linux.
I managed to add my db file to assets through the following code in my .pro file

deployment.files += rako.db
deployment.path = /assets
INSTALLS += deployment

Now in my DbManager C++ file where I handle my Database Connections I'm not able to get the SQLite database running :(
[...]
db_.setDatabaseName("assets:/rako.db");

After reading some of the posts at stackoverflow I'm still not able to get this accomplished.
Do I miss something?

Thanks guys,

Max

[Violet Giraffe]

@KMax

1. To access Android assets from C++ you need AAssetManager API.
2. Since you're working with this file from C++, it's easier to bundle it as a Qt resource. Of course, if it's very large that may not be a good idea.
3. If your database is NOT read-only, AFAIK you won't be able to modify its asset in-place. Copy it to your /data folder when initializing the app and then work with it there.

[KMax]

Hi Violet Giraffe,

thank you for your reply.
I tried to load the database as a qrc - resouce, but nonetheless it doesn't work.

db_.setDatabaseName("qrc:/database/rako.db");

But it just returns me the following error:
connection failed "out of memory Error opening database"

What are the steps I'll have to do?

• add it to the qrc items

• load it with the setDatabaseName() ?

• afterwards copy it?

Tank you

[KMax]

For everyone else who is have the same problem, this did the trick:

.pro file:

android {
    data.files = db/flags.sqlite
    data.path = /assets/db
    INSTALLS += data
}

.cpp file

  QFile dfile("assets:/db/flags.sqlite");
   QString filePath = QStandardPaths::writableLocation( QStandardPaths::StandardLocation::AppLocalDataLocation );
   filePath.append( "/flags.sqlite");
   if (dfile.exists()) {
       if( QFile::exists( filePath ) )
           QFile::remove( filePath );

       if( dfile.copy( filePath ) )
           QFile::setPermissions( filePath, QFile::WriteOwner | QFile::ReadOwner );

   }
   d->database.setDatabaseName( filePath );
#else
   d->database.setDatabaseName( "db/flags.sqlite" );
#endif

   if( d->database.open() ) {
       qDebug( "DB open successful ");

       QSqlQuery q(d->database);
       q.exec("SELECT * from flags");
       q.last();
       d->dbSize = q.at() + 1;
   }
   else {
       qDebug( "DB failed" );
   }
}

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