Qt SCXML Media Player QML Example (Static)▲
Media Player QML 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 Quick.
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:
<scxml
xmlns="http://www.w3.org/2005/07/scxml"
version="1.0"
name="MediaPlayerStateMachine"
initial="stopped"
datamodel="ecmascript"
>
<datamodel>
<data id="media"/>
</datamodel>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:▲
QT += widgets scxmlWe then specify the state machine to compile:
STATECHARTS = ../mediaplayer-common/mediaplayer.scxmlCMakeLists.txt when using cmake:▲
find_package(Qt6 REQUIRED COMPONENTS Core Gui Scxml Widgets)
target_link_libraries(mediaplayer-widgets-static PUBLIC
Qt6::Core
Qt6::Gui
Qt6::Scxml
Qt6::Widgets
)We then specify the state machine to compile:
qt6_add_statecharts(mediaplayer-widgets-static
../mediaplayer-common/mediaplayer.scxml
)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-qml-static.cpp:
#include "mediaplayer.h"
int main(int argc, char *argv[])
{
QGuiApplication app(argc, argv);
qmlRegisterType<MediaPlayerStateMachine>("MediaPlayerStateMachine", 1, 0, "MediaPlayerStateMachine");
QQmlApplicationEngine engine;
engine.load(QUrl(QStringLiteral("qrc:///mediaplayer-qml-static.qml")));
if (engine.rootObjects().isEmpty())
return -1;
return app.exec();
}