Expose QML singletons to Java

Why?

Cause

• Java/Kotlin Android developers (users of QtQuickView) cannot interact with QML singletons (objects defined with pragma Singleton in QML) through the Java/Kotlin interface.
• Singletons are critical for managing global states or utilities in QML applications, and the lack of direct support limits their usability in hybrid Android apps.

Customer

• ?
• Technically less important than multi-args and easier to work around

Cruft

What?

Definition

• This ticket proposes adding API methods to QtQuickView and maybe QtQuickViewContent to:

• Access and modify properties of QML singletons.
• Connect to signals emitted by QML singletons.
• Possibly invoke functions of the singleton (if we generally add the support for non-singletons)
• This functionality would mirror existing capabilities for regular QML components (e.g., QtQuickViewContent interactions) and provide an easy way to integrate singleton-based logic into Android workflows.

Demarcation

• What this is not? soarmin __

Dependencies

• FF (end of May 2025) dependent 6.10 for the new API
•