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:

Example project @ code.qt.io