Widgets

Widgets can be related to a particular AC, or not.

If related to an AC, it will be intanciated for each AC, and grouped under a list or a stack container.

To access the Aircraft’s data, use:

Aircraft* ac = pprzApp()->toolbox()->aircraftManager()->getAircraft(ac_id);

See Aircraft.

Creating a new widget

Create your widget, inheriting QWidget.

For an AC related widget, the constructor must be of this form:

MyAwesomeWidget::MyAwesomeWidget(QString ac_id, QWidget *parent)

Put your files in the src/widgets/ directory, and add the cpp filename to src/widgets/CMakeLists.txt

Add your widget type in the appropriate lists in the src/widgets/widget_utils.cpp file:

  • the ac_widgets list is forwidgets related to an AC

  • simple_widgets is for widgets not related to a specific AC.

  • containers is for container widgets (containing AC widgets)

You need to add it in the type definition (the using... lines), and in the map definition. The first element in the map definition is the designator of the widget in layout files.

Typical widget architecture

typically, a widget will connect to some signals to update its data accordingly.

With AircraftStatus

Binding to AircraftStatus’s signal is the easiest way to get AC data.

In this extract of the MiniStrip widget constructor, it connects to 3 signals and update widget’s data in the corresponding slots:

auto ac_status = AircraftManager::get()->getAircraft(ac_id)->getStatus();
connect(ac_status, &AircraftStatus::engine_status, this, &MiniStrip::updateData);
connect(ac_status, &AircraftStatus::flight_param, this, &MiniStrip::updateData);
connect(ac_status, &AircraftStatus::telemetry_status, this, &MiniStrip::updateData);

With PprzDispatcher

The signals emitted by AircraftsStatus are also emitted by the PprzDispatcher. It is usefull to bind to these signals to receive the corresponding message for any AC. This is the case for the map, that is not related to a particular AC:

connect(pprzApp()->toolbox()->pprzDispatcher(), &PprzDispatcher::circle_status, this, &MapWidget::updateNavShape);

Connect to any message

Finally, you can bind a callback to any message with the PprzDispatcher’s bind method that returns the bind id, needed to unbind.

using messageCallback_t = std::function<void(QString, Message)>;
long PprzDispatcher::bind(QString msg_name, QObject* context, pprzlink::messageCallback_t cb);

pprzApp()->toolbox()->pprzDispatcher()->bind("INTRUDER", this,
        [=](QString sender, pprzlink::Message msg) {
            onIntruder(sender, msg);
        });

Warning

When using lambdas, always specify a context object (often this), otherwise Qt won’t be able to disconnect the signal when the object is destroyed, leading to a use after free.