QML app hangs on QQmlApplicationEngine::load()

aatwo · wrote on 10 Aug 2021, 17:45

Hi all. I have a QML app (Qt 5.14.2) which I created on machine-1 without issue. I just tried running it on machine-2 with all the dependencies gathered using the win deploy tool but nothing would appear. The app was running in the process manager but nothing was appearing on-screen.

So after setting up a development environment on machine-2 and running a debug build it appears to be hanging for some reason on the following line:

engine.load(QUrl(QStringLiteral("qrc:/qml/mainwindow.qml")));

Anyone have any ideas on how I can debug this or attempt to resolve it? I have several or so simple QML apps from machine-1 which all seem to exhibit the same issue on machine-2 and I get absolutely no log output.

Very simple QML apps seem to work ok (e.g. the swipe template).

aatwo · wrote on 10 Aug 2021, 19:07

Ok I was being ever so slightly impatient. The app does eventually open but it takes around 10-12 minutes. Anyone know what might cause such insane load times for a small QML application?

I tried a couple of things to force software rendering but this yeilded no gain :(

aatwo · 11 Aug 2021, 04:57

The plot thickens. So taking out all references to FileDialog removes the start-up penalty completely. I have a number of FileDialogs spread across my application and it seems there is some fixed penalty for each FileDialog that is declared. Something like a full minute per dialog...

Anyone got any workarounds for this?

jeremy_k · wrote on 11 Aug 2021, 04:52

Try the QML profiler in Creator, and/or turning on categorized logging.

J.Hilk · A aatwo 10 Aug 2021, 19:51

@aatwo 2 options you can try:

1: Update the Qt version used and or the windows its running on.

I had some serious issues on QML load times on iOS that suddenly appeared and suddenly went away. Each happening with an update of the Xcode SDK

2: What File dialog are you using?

try other other one from what you're currently using, they are I fact quite different.