Access Documents/Pictures folder on Android

Holger Gerth

I'm trying to access and list the files in the Document/Pictures folder on Android via QDir::entryInfoList but no content is found:

QStringList paths = QStandardPaths::standardLocations(QStandardPaths::PicturesLocation);

foreach (auto path, paths) {
  qDebug() << "path: " << path;
  QDir directory(path);
  qDebug() << "EntryList: " << directory.entryList();
  qDebug() << "FileInfoList: " <<  directory.entryInfoList();
}

On desktop, this code is working find, delivering the content of the users pictures folder. On Android I get these results:

D MyApp: path:  "/storage/emulated/0/Pictures"
D MyAppr: EntryList:  ()
D MyApp: FileInfoList:  ()
D MyApp: path:  "/storage/emulated/0/Android/data/de.myorg.myapp/files/Pictures"
D MyApp: EntryList:  (".", "..")
D MyApp: FileInfoList:  (QFileInfo(/storage/emulated/0/Android/data/de.myorg.myapp/files/Pictures/.), QFileInfo(/storage/emulated/0/Android/data/de.myorg.myapp/files/Pictures/..))

But there are files in the pictures folder of the device. And the path should be correct.

Read external storage permission is set in the AndroidManifest.xml.

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

Any ideas what I'm doing wrong? Or is this a bug in QDir?

KroMignon

@Holger-Gerth Welcome to Qt Forum, which Qt version are you using and with Android version do you targeting?

Have you checked READ_EXTERNAL_STORAGE permission is granted to your app?

You could do it with something like this:

bool checkPermissions()
{
    bool success = true;
    if(QtAndroid::androidSdkVersion() >= 23)
    {
        static const QVector<QString> permissions({
            "android.permission.READ_EXTERNAL_STORAGE"
        });

        for(const QString &permission : permissions)
        {
            // check if permission is granded
            auto result = QtAndroid::checkPermission(permission);
            if(result != QtAndroid::PermissionResult::Granted)
            {
                // request permission
                auto resultHash = QtAndroid::requestPermissionsSync(QStringList({permission}));
                if(resultHash[permission] != QtAndroid::PermissionResult::Granted)
                {
                    qDebug() << "Fail to get permission" << permission;
                    success = false;
                }
                else
                {
                    qDebug() << "Permission" << permission << "granted!";
                }
            }
            else
            {
                qDebug() << "Permission" << permission << "already granted!";
            }
        }
    }
    return success;
}

Holger Gerth

Android target sdk level is 28,
Qt version is 5.15.0

That was the solution, thank you. I wasn't aware that I have to explicitly check for the permission. I thought that this will be done on installation/startup time via the manifest.

KroMignon

@Holger-Gerth said in Access Documents/Pictures folder on Android:

That was the solution, thank you. I wasn't aware that I have to explicitly check for the permission. I thought that this will be done on installation/startup time via the manifest.

Your welcome :)
Permission check policy changes with each new Android API level, so it depends which is the Android device you are targeting.