Qt SCXML Media Player Example (Static)#
A widget-based application that sends data to and receives it from a compiled ECMAScript data model.
Media Player Example (Static) demonstrates how to access data from an ECMAScript data model that is compiled into a C++ class.
The UI is created using Qt Widgets.
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.
Using the ECMAScript Data Model#
We specify the data model as a value of the datamodel attribute of the <scxml> element in mediaplayer-common/mediaplayer.scxml:
Compiling the State Machine#
We link against the Qt SCXML module by adding the following lines to the example’s build files.
.pro*
when using qmake:#
We then specify the state machine to compile:
CMakeLists.txt*
when using cmake:#
We then specify the state machine to compile:
The statechart directives STATECHARTS or qt6_add_statecharts invoke the Qt SCXML Compiler, qscxmlc, which is run automatically to generate a header and a source file, which are then added appropriately for compilation.
Instantiating the State Machine#
We instantiate the generated MediaPlayerStateMachine class in mediaplayer-widgets-static.cpp:
Connecting to States#
The media player state machine will send out events when users tap a control and when playback starts or stops, as specified in the SCXML file:
To be notified when a state machine sends out an event, we connect to the corresponding signals: