Qt SCXML Invoke Example (Dynamic)▲
Invoke Example (Dynamic) demonstrates how to use the <invoke> element with generated nested state-machines, where the SCXML file is dynamically loaded. The <invoke> element is used to create an instance of an external service.
Running the Example▲
To run the example from Qt Creator, open the Welcome mode and select the example from Examples. For more information, visit Building and Running an Example.
Invoking the State Machine▲
In statemachine.scxml, we specify a state machine with the name Directions of type http://www.w3.org/TR/scxml/ to invoke:
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<scxml
xmlns="http://www.w3.org/2005/07/scxml"
version="1.0"
name="Directions"
initial="anyplace"
>
<state id="anyplace">
<transition event="goNowhere" target="nowhere"/>
<transition event="goSomewhere" target="somewhere"/>
<state id="nowhere"/>
<state id="somewhere">
<invoke type="http://www.w3.org/TR/scxml/">
<content>
<scxml name="anywhere" version="1.0">
<state id="here">
<transition event="goThere" target="there"/>
</state>
<state id="there">
<transition event="goHere" target="here"/>
</state>
</scxml>
</content>
</invoke>
</state>
</state>
</scxml>Dynamically Loading the State Machine▲
We link against the Qt SCXML module by adding the following line to the project build files.
With qmake to the invoke-dynamic.pro
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QT += qml scxmlWith cmake to the CMakeLists.txt
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find_package(Qt6 REQUIRED COMPONENTS Core Gui Qml Scxml)
target_link_libraries(invoke-dynamic PUBLIC
Qt6::Core
Qt6::Gui
Qt6::Qml
Qt6::Scxml
)We dynamically create the state machine, as follows:
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import QtScxml
MainView {
stateMachine: directions.stateMachine
StateMachineLoader {
id: directions
source: "qrc:///statemachine.scxml"
}