Qt Android Precise Location Issue

myzinsky

I implemented a class that gives me the GPS-Location for my app. Here a minimal example:

rbManager::rbManager(QObject *parent)
    : QAbstractListModel(parent)
{
    nm = nullptr;
    initialized = false;

    QLocationPermission locationPermission;
    locationPermission.setAccuracy(QLocationPermission::Precise);

    if(qApp->checkPermission(locationPermission) != Qt::PermissionStatus::Granted) {
        qApp->requestPermission(QLocationPermission{}, this, &rbManager::permissionUpdated);
    } else {
        qDebug() << "PERMISSION ALREADY GRANTED";
        init();
    }
}

void rbManager::permissionUpdated(const QPermission &permission) {
    if (permission.status() == Qt::PermissionStatus::Granted) {
        qDebug() << "PERMISSION GRANTED";
        init();
    } else {
        qDebug() << "PERMISSION NOT GRANTED";
    }
}

The init function does something with the gps coordinates. On iOS everything works like expected. However on Android it does not work!

I did everything which was mentioned in the qt6 docs: https://doc.qt.io/qt-6/qlocationpermission.html

I used QLocationPermission::Precise as you can see in my C++ code. And I put this

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

in my manifest.

On the console I get this output:

D libCloudLogOffline_arm64-v8a.so: INIT
I qt.positioning.android: Unknown positioningMethod
I qt.positioning.android: Unknown positioningMethod
W qt.positioning.android: : Position data not available due to missing permission

So what I'm doing wrong here?

Edit: Also I should mention, that when the app is installed and started for the first time, I'm asked only for approximate location... Maybe there is a bug in Qt?

ekkescorner

@myzinsky have you tried to request per mission for Precise and Approximate location ?

Mesrine

@myzinsky
I am getting the same error when getting Precise location.
But if use Approximate it works.

Edit: Checking Precise location permission also works.

The error: Position data not available due to missing permission
was due to using an active qml PositionSource without granting the permissions.
I think this could change in the next run :).

ekkescorner

@Mesrine both together don't work ? I mean: at first request Approximate, then Precise
or what happens with both in Manifest and then request only Precise

Mesrine

@ekkescorner

Now it is working asking for Precise location.
I tried asking first Aproximate and then Precise but I think once you ask for Aproximate, asking(qApp->checkPermission(lPermission)) later for Precise will give Qt::PermissionStatus::Denied

I have edited my previous comment.

myzinsky

@Mesrine

So now, I ask for approx. first and then for precise.

I qt.positioning.android: Unknown positioningMethod
I qt.positioning.android: Unknown positioningMethod
W qt.positioning.android: : Position data not available due to missing permission

still I get this warning, and I don't see the GPS coordinates dropping out as for iOS :-(

ekkescorner

@myzinsky from my understanding @Mesrine now only asks for Precise and it's important to ask for permission before using PositionSource

Mesrine

@ekkescorner

Exactly. In my case the warning W qt.positioning.android: : Position data not available due to missing permission was because I had an active position source without having granted location permissions.

My recommendation is to ask for permission(approximate or precise) first and check that all the properties/bindings that need the coordinates work after the permission is granted.

I qt.positioning.android: Unknown positioningMethod i do not know where is coming.

myzinsky

@Mesrine @ekkescorner

But I think that's what im doing, I check first of all for all permissions and then I initialize positioning with my init() method.

Side note: When I ask for the permissions already at app start, in the constructor of my class, the app crashes because I think the QML cannot be loaded. Therefore I call the checkPermissions function before I want to get GPS coordinates.

You can see my code here:

1st: QML call: https://github.com/myzinsky/cloudLogOffline/blob/d374acba334ff6cb33fb57bf7ef9d94f2dcb84b5/qml/SettingsView.qml#L197
2nd: C++ processing: https://github.com/myzinsky/cloudLogOffline/blob/d374acba334ff6cb33fb57bf7ef9d94f2dcb84b5/src/repeatermodel.cpp#L51

That is the output:

D libCloudLogOffline_arm64-v8a.so: PRECISE PERMISSION GRANTED
D libCloudLogOffline_arm64-v8a.so: INIT
I qt.positioning.android: Unknown positioningMethod
I qt.positioning.android: Unknown positioningMethod
W qt.positioning.android: : Position data not available due to missing permission

So permission was granted and I don't get coordinates. Although I do it in the order that you propose.

Mesrine

@myzinsky

I think this
qApp->requestPermission(QLocationPermission{}, this, &rbManager::precisePermissionUpdated);
should be
qApp->requestPermission(preciselocationPermission, this, &rbManager::precisePermissionUpdated);
With this, you will be asking for precise location permission.
Also
qApp->requestPermission(QLocationPermission{}, this, &rbManager::precisePermissionUpdated);

execute
void rbManager::precisePermissionUpdated(const QPermission &permission)
But I am not sure about the function arguments const QPermission &permission .
Normally what I do is to check for permission again after
qApp->requestPermission
As explained here.
This is how I do it here
Sorry, I did not notice this before on the post.

myzinsky

@Mesrine Okay, that was dumb :-D just a copy-paste issue ... Thanks anyway for the help! Now it works.