Deployment on Windows - app runs but doesn't show

[Eeli K]

Windows 7, Qt 5.7.0 mingw. I'm trying to deploy a qml app for Windows, using the windeployqt. So far I have succeeded to start the app so that it runs without complaining about missing dll's or anything. These are the first lines of the cpp code:

int main(int argc, char *argv[])
{
    std::cout << "MAIN has started" << std::endl << std::flush;
    qDebug() << "MAIN has started";
    qSetMessagePattern("%{function} %{line}: %{message}");

    Tools* tools = new Tools();
    QGuiApplication::setAttribute(Qt::AA_EnableHighDpiScaling, Tools::getUiScaling());
    QQuickStyle::setStyle(Tools::getStyle());
std::cout << "app will be created"<< std::endl << std::flush;
    QApplication* app = new QApplication(argc, argv);
    QQmlApplicationEngine* engine = new QQmlApplicationEngine();
    QQmlContext* ctx = engine->rootContext();
    Connection* conn = new Connection();
    ProfileData* data = new ProfileData(ctx, conn);
    Monitoring* monitoring = new Monitoring(conn);
std::cout << "app classes were created"<< std::endl << std::flush;

    ctx->setContextProperty("qApplication", app);
    ctx->setContextProperty("profileData", data);
    ctx->setContextProperty("connection", conn);
    ctx->setContextProperty("tools", tools);
    ctx->setContextProperty("monitoringData", monitoring);
    std::cout << "appengine will be created"<< std::endl << std::flush;
    engine->load(QUrl(QStringLiteral("qrc:/main.qml")));

    qDebug() << "EXECUTE APP";
    std::cout << "app will be executed"<< std::endl << std::flush;
    int exitcode = app->exec(); // 1 means "restart"
    qDebug() << "APP WAS EXECUTED";

and this is the output when I start the app from the (cygwin) command line:

MAIN has started
app will be created
app classes were created
appengine will be created
app will be executed

Then nothing else happens; the application is still running, but it doesn't use CPU or do anything else. If I run it from QtCreator it behaves normally, first it prints

MAIN has startedMAIN has started

as expected and then works fine (opens a window etc.). This fine working .exe I have copied to a new directory where I run

windeployqt.exe  --qmldir ../projectsrc/ ./

I just have to copy some non-qt .dll's from the Qt's bin directory manually. But even copying all of the .dll's from bin/ doesn't help.

These are the directories created by windeployqt: bearer/ iconengines/ imageformats/ Material/ platforms/ private/ qml/ qmltooling/ Qt/ QtGraphicalEffects/ QtQml/ QtQuick.2/ QtQuick/ translations/ Universal/. I think it should be all that's needed, I don't use any plugins or fancy extra.

[Eeli K]

I finally found out the reason. I started the .exe from QtCreator as an external app and the debuggin message told that module QtQuick.Controls is not installed. Windeployqt.exe didn't deploy the necessary files, I don't know why. It was solved by manually copying 5.7\mingw53_32\qml\QtQuick\Controls\ to the target QtQuick\Controls.