QML and Qt Quick

Hey @eternal_void , I just got back to using Qt for another project. This is new account (I was @talksik), but here are my findings in a similar post after a ton of research and coming up with a custom solution not really mentioned anywhere: https://forum.qt.io/post/821291

This has been a question of mine for over a year. I resorted to having a factory class that has methods to instantiate various view models (and pass in dependencies) and return the pointer to that view model. This factory would be exposed to QML via singleton or contextProperty at the start of my program. Any QML view can decide which view models it wants and doesn't deal with dependency injection.

Here is an example:

class ViewModelFactory : public QObject { Q_OBJECT QML_ELEMENT QML_SINGLETON public: Q_INVOKABLE HomeViewModel* createHomeViewModel(QObject* parent = nullptr) { // Inject dependencies from ApplicationModels auto& appModels = ApplicationModels::instance(); return new HomeViewModel(appModels.smartHomeService(), appModels.userService(), parent); } };

Now, the above example makes ApplicationModels a singleton and passes it to the view model, but you could imagine a world where the factory can manage the dependencies without them being singletons.

It took a lot of thinking and I gathered this approach by looking at how QtWidgets does things: a very hierarchical object structure where the MainWindow class would contain everything within it and proctor instantiation, DI, and more.

QML just has access to what is publicly exposed by the ApplicationModel/factory, and no longer needs access to dependencies for ViewModels to use their desired view model.

Note: I have not tested this yet (my fear being that I do NOT know the impact of calling factory methods on init of a Qml component)

Hi and welcome to devnet,

Just a quick that came to mind: what about adding the primary screen widget as last ?

The error you're encountering ("QML Image: SSL handshake failed") typically happens when there's a problem establishing a secure connection between the QML application and the server you're trying to connect to. This is often caused by issues with SSL certificates, the server's configuration, or network problems. To resolve this error, you can try the following steps:

Check SSL/TLS Configuration: Ensure that the server you're connecting to has a valid SSL certificate. If you're using a self-signed certificate, it may not be trusted by the system. Make sure the certificate is correctly installed.

Update QML/Qt and SSL Libraries: Sometimes, outdated libraries can cause compatibility issues. Make sure you're using the latest version of QML, Qt, and SSL libraries (OpenSSL).

Verify Network and Proxy Settings: If you're behind a proxy or firewall, ensure the settings are properly configured and not blocking the SSL handshake.

Trust Certificates: If the certificate isn't recognized by the system, you may need to manually add the certificate to the trust store.

Enable Debugging: You can enable debugging in Qt to get more information about the SSL handshake failure. Set the following environment variable before running your application:

ini
Copy
Edit
QT_DEBUG_PLUGINS=1
For more detailed information and troubleshooting, you can refer to the following resources:

Qt SSL documentation
OpenSSL documentation
Common SSL handshake errors
Let me know if you need more help!

Ah, didn't read this. Thanks for the hint...

There was a similar question the other day and this was what I said:

I recall having to try a few things when I first wanted to do this a few years ago. I don't know if what I arrived at is the "correct" approach, but the format that I found to work in QML and have stuck to ever since involves using a triple forward slash like this:

source: "qrc:///images/my-image.png"

As it's something that keeps popping up, I'd be interested to see some clarification on this from experts. I don't know if QML introduces any quirks above and beyond what is described in the resources chapter in the docs, which does not explicitly mention QML.

Snipaste_2025-02-21_19-04-28.jpg
The complete picture looks like this

Checkable and checked are not components of Button QML.

A similar question here; https://forum.qt.io/topic/36479/solved-button-checkable-and-checked-not-working albeit a different answer/outcome from my response. Regardless, I still myself, cannot use checkable or checked with Button.

@SGaist Thank you so much!

It turns out wrapping the child Layout in an Item does the trick. Don't know why and whether this is the best solution

import QtQuick import QtQuick.Controls import QtQuick.Layouts Window { height: 300 width: 240 visible: true StackLayout { anchors.fill: parent Item { Layout.fillWidth: true Layout.fillHeight: true ColumnLayout { anchors.fill: parent Rectangle { color: "red" Layout.preferredWidth: 100 Layout.preferredHeight: 50 Layout.alignment: Qt.AlignHCenter // Center within ColumnLayout } // other items } } // other items } }

@VITORdk said in Error: ":\Qt\6.7.3\android_arm64_v8a\include\QtCore\qnamespace.:24:1: error: error: Parse error at "__attribute__"":

So I reduced my file to an empty file

You can't compile an empty file. Also, I guess your project consists of more than just an empty file.
Please provide more information, else nobody knows what you're doing and what the problem is.
Did you try to create a new widget project in QtCreator and build it for Android?

Fixed in 6.8.2