关于QGroundControl的软件架构的理解

首先QGC是基于QT平台开发，个人理解软件架构即为项目前后端结构，以及前后端数据交互的逻辑。下面是对QGroundControl源码的一些个人理解，写这个博客只是为了记录下来，防止时间久了忘记，过程中看了一些大佬的博客来帮助理解，感谢一下大佬：

火山上的企鹅

阿木实验室

望天边星宿

前言

• 前端qml结构

QGC的前端主要为五个主要页面和一个顶栏：

MainToolBar(顶栏)

AppSetting.qml

SetupView.qml

PlanView.qml

FlightDispalyView.qml

AnalyzeView.qml

• 后端类结构

 前端显示与后端逻辑进行数据交互，即实现了QGC地面站功能。

架构理解

架构理解可以从QGC的运行main函数开始逐步理解。

• main.cc

在main.cc中有几个关键程序

创建QGCApplication实例，QGCApplication是QGroundControl中的核心类，提供了应用程序的生命周期管理、连接管理、飞行日志管理、地图和任务管理、设置和配置管理，以及警报和通知管理等功能。它扮演着关键角色。这个类只提供了唯一的实例，另外提供了一个访问它的全局函数QGCApplication* qgcApp(void){}

QGCApplication* app = new QGCApplication(argc, argv, runUnitTests);

在_initCommon()中将C++类注册，在前端qml中可以调用，实现前后端数据交互。在

qgroundcontrolQmlGlobalSingletonFactory中将QGroundControlQmlGlobal类实例化为单例工厂QGroundControl。

app->_initCommon()
{
    static const char* kRefOnly         = "Reference only";
    static const char* kQGroundControl  = "QGroundControl";
    static const char* kQGCControllers  = "QGroundControl.Controllers";
    static const char* kQGCVehicle      = "QGroundControl.Vehicle";
 
    QSettings settings;
 
    // Register our Qml objects
 
    qmlRegisterType<QGCPalette>     ("QGroundControl.Palette", 1, 0, "QGCPalette");
    qmlRegisterType<QGCMapPalette>  ("QGroundControl.Palette", 1, 0, "QGCMapPalette");
 
    qmlRegisterUncreatableType<Vehicle>                 (kQGCVehicle,                       1, 0, "Vehicle",                    kRefOnly);
    qmlRegisterUncreatableType<MissionManager>          (kQGCVehicle,                       1, 0, "MissionManager",             kRefOnly);
    qmlRegisterUncreatableType<ParameterManager>        (kQGCVehicle,                       1, 0, "ParameterManager",           kRefOnly);
    qmlRegisterUncreatableType<VehicleObjectAvoidance>  (kQGCVehicle,                       1, 0, "VehicleObjectAvoidance",     kRefOnly);
    qmlRegisterUncreatableType<QGCCameraManager>        (kQGCVehicle,                       1, 0, "QGCCameraManager",           kRefOnly);
    qmlRegisterUncreatableType<QGCCameraControl>        (kQGCVehicle,                       1, 0, "QGCCameraControl",           kRefOnly);
    qmlRegisterUncreatableType<QGCVideoStreamInfo>      (kQGCVehicle,                       1, 0, "QGCVideoStreamInfo",         kRefOnly);
    qmlRegisterUncreatableType<LinkInterface>           (kQGCVehicle,                       1, 0, "LinkInterface",              kRefOnly);
    qmlRegisterUncreatableType<MissionController>       (kQGCControllers,                   1, 0, "MissionController",          kRefOnly);
    qmlRegisterUncreatableType<GeoFenceController>      (kQGCControllers,                   1, 0, "GeoFenceController",         kRefOnly);
    qmlRegisterUncreatableType<RallyPointController>    (kQGCControllers,                   1, 0, "RallyPointController",       kRefOnly);
 
    qmlRegisterUncreatableType<MissionItem>         (kQGroundControl,                       1, 0, "MissionItem",                kRefOnly);
    qmlRegisterUncreatableType<VisualMissionItem>   (kQGroundControl,                       1, 0, "VisualMissionItem",          kRefOnly);
    qmlRegisterUncreatableType<CoordinateVector>    (kQGroundControl,                       1, 0, "CoordinateVector",           kRefOnly);
    qmlRegisterUncreatableType<QmlObjectListModel>  (kQGroundControl,                       1, 0, "QmlObjectListModel",         kRefOnly);
    qmlRegisterUncreatableType<MissionCommandTree>  (kQGroundControl,                       1, 0, "MissionCommandTree",         kRefOnly);
    qmlRegisterUncreatableType<CameraCalc>          (kQGroundControl,                       1, 0, "CameraCalc",                 kRefOnly);
    qmlRegisterUncreatableType<LogReplayLink>       (kQGroundControl,                       1, 0, "LogReplayLink",              kRefOnly);
    qmlRegisterType<LogReplayLinkController>        (kQGroundControl,                       1, 0, "LogReplayLinkController");
#if defined(QGC_ENABLE_MAVLINK_INSPECTOR)
    qmlRegisterUncreatableType<MAVLinkChartController> (kQGroundControl,                    1, 0, "MAVLinkChart",               kRefOnly);
#endif
#if defined(QGC_ENABLE_PAIRING)
    qmlRegisterUncreatableType<PairingManager>      (kQGroundControl,                       1, 0, "PairingManager",             kRefOnly);
#endif
 
    qmlRegisterUncreatableType<AutoPilotPlugin>     ("QGroundControl.AutoPilotPlugin",      1, 0, "AutoPilotPlugin",            kRefOnly);
    qmlRegisterUncreatableType<VehicleComponent>    ("QGroundControl.AutoPilotPlugin",      1, 0, "VehicleComponent",           kRefOnly);
    qmlRegisterUncreatableType<JoystickManager>     ("QGroundControl.JoystickManager",      1, 0, "JoystickManager",            kRefOnly);
    qmlRegisterUncreatableType<Joystick>            ("QGroundControl.JoystickManager",      1, 0, "Joystick",                   kRefOnly);
    qmlRegisterUncreatableType<QGCPositionManager>  ("QGroundControl.QGCPositionManager",   1, 0, "QGCPositionManager",         kRefOnly);
    qmlRegisterUncreatableType<FactValueSliderListModel>("QGroundControl.FactControls",     1, 0, "FactValueSliderListModel",   kRefOnly);
 
    qmlRegisterUncreatableType<QGCMapPolygon>       ("QGroundControl.FlightMap",            1, 0, "QGCMapPolygon",              kRefOnly);
    qmlRegisterUncreatableType<QGCGeoBoundingCube>  ("QGroundControl.FlightMap",            1, 0, "QGCGeoBoundingCube",         kRefOnly);
    qmlRegisterUncreatableType<TrajectoryPoints>    ("QGroundControl.FlightMap",            1, 0, "TrajectoryPoints",           kRefOnly);
 
    qmlRegisterType<QGCMapCircle>                   ("QGroundControl.FlightMap",            1, 0, "QGCMapCircle");
 
    qmlRegisterType<ParameterEditorController>      (kQGCControllers,                       1, 0, "ParameterEditorController");
    qmlRegisterType<ESP8266ComponentController>     (kQGCControllers,                       1, 0, "ESP8266ComponentController");
    qmlRegisterType<ScreenToolsController>          (kQGCControllers,                       1, 0, "ScreenToolsController");
    qmlRegisterType<PlanMasterController>           (kQGCControllers,                       1, 0, "PlanMasterController");
    qmlRegisterType<ValuesWidgetController>         (kQGCControllers,                       1, 0, "ValuesWidgetController");
    qmlRegisterType<QGCFileDialogController>        (kQGCControllers,                       1, 0, "QGCFileDialogController");
    qmlRegisterType<RCChannelMonitorController>     (kQGCControllers,                       1, 0, "RCChannelMonitorController");
    qmlRegisterType<JoystickConfigController>       (kQGCControllers,                       1, 0, "JoystickConfigController");
    qmlRegisterType<LogDownloadController>          (kQGCControllers,                       1, 0, "LogDownloadController");
    qmlRegisterType<SyslinkComponentController>     (kQGCControllers,                       1, 0, "SyslinkComponentController");
    qmlRegisterType<EditPositionDialogController>   (kQGCControllers,                       1, 0, "EditPositionDialogController");
 
#ifndef __mobile__
#ifndef NO_SERIAL_LINK
    qmlRegisterType<FirmwareUpgradeController>      (kQGCControllers,                       1, 0, "FirmwareUpgradeController");
#endif
#endif
    qmlRegisterType<GeoTagController>               (kQGCControllers,                       1, 0, "GeoTagController");
    qmlRegisterType<MavlinkConsoleController>       (kQGCControllers,                       1, 0, "MavlinkConsoleController");
#if defined(QGC_ENABLE_MAVLINK_INSPECTOR)
    qmlRegisterType<MAVLinkInspectorController>     (kQGCControllers,                       1, 0, "MAVLinkInspectorController");
#endif
    // Register Qml Singletons
    qmlRegisterSingletonType<QGroundControlQmlGlobal>   ("QGroundControl",                          1, 0, "QGroundControl",         qgroundcontrolQmlGlobalSingletonFactory);
    qmlRegisterSingletonType<ScreenToolsController>     ("QGroundControl.ScreenToolsController",    1, 0, "ScreenToolsController",  screenToolsControllerSingletonFactory);
    qmlRegisterSingletonType<ShapeFileHelper>           ("QGroundControl.ShapeFileHelper",          1, 0, "ShapeFileHelper",        shapeFileHelperSingletonFactory);
}

在_initForNormalAppBoot()中进行启动初始化，加载qml文件。

app->_initForNormalAppBoot()
 
QQmlApplicationEngine* QGCCorePlugin::createRootWindow(QObject *parent)
{
    QQmlApplicationEngine* pEngine = new QQmlApplicationEngine(parent);
    pEngine->addImportPath("qrc:/qml");
    // 注册为对象在qml中直接使用，不需要import
    pEngine->rootContext()->setContextProperty("joystickManager", qgcApp()->toolbox()->joystickManager());
    pEngine->rootContext()->setContextProperty("debugMessageModel", AppMessages::getModel());
    pEngine->load(QUrl(QStringLiteral("qrc:/qml/MainRootWindow.qml")));
    return pEngine;
}

• 整体架构

想要搞明白整体架构就需要理解QGCApplication类、QGCToolBox类、QGroundControlQmlGlobal类和QGCtool类。

QGCApplication类中新建了QGCToolbox类，在QGCToolbox类初始化时需要传入QGCApplication类，这样通过qgcAPP()->toolBox()就可以获取到功能类的所有属性。

QGCToolBox类是一个大的工具类，QGC的所有功能类都在这个toolBox中进行实例化，使用toolBox提供的接口即可调用类的属性和方法。

在QGroundControlQmlGlobal中通过Q_PROPERTY将功能类的属性和方法共前端可以调用，setToolbox()方法将所有功能类使用指针地址连接到QGCToolBox定义的功能类，所以QGroundControlQmlGlobal是前端获取后端数据的总接口。上边的单例工厂实例化将QGroundControlQmlGlobal实例化为QGroundControl，则前端qml通过import 即可实现调用C++类。

还有一个QGCTool类，所有的功能类都继承了QGCTool。在QGCTool类型定义了QGCApplication* _app;和QGCToolbox* _toolbox;和(QGCApplication* app, QGCToolbox* toolbox)方法，即每个功能类都都有QGCApplication和QGCToolbox，并且都指向同一个QGCApplication和QGCToolbox，即QGCApplication中的_app和_toolBox.这样实现了各个功能类的互通。

QGCToolbox::QGCToolbox(QGCApplication* app)
{
    // SettingsManager must be first so settings are available to any subsequent tools
    _settingsManager        = new SettingsManager           (app, this);
    //-- Scan and load plugins
    _scanAndLoadPlugins(app);
    _audioOutput            = new AudioOutput               (app, this);
    _factSystem             = new FactSystem                (app, this);
    _firmwarePluginManager  = new FirmwarePluginManager     (app, this);
#ifndef __mobile__
    _gpsManager             = new GPSManager                (app, this);
#endif
    _imageProvider          = new QGCImageProvider          (app, this);
    _joystickManager        = new JoystickManager           (app, this);
    _linkManager            = new LinkManager               (app, this);
    _mavlinkProtocol        = new MAVLinkProtocol           (app, this);
    _missionCommandTree     = new MissionCommandTree        (app, this);
    _multiVehicleManager    = new MultiVehicleManager       (app, this);
    _mapEngineManager       = new QGCMapEngineManager       (app, this);
    _uasMessageHandler      = new UASMessageHandler         (app, this);
    _qgcPositionManager     = new QGCPositionManager        (app, this);
    _followMe               = new FollowMe                  (app, this);
    _videoManager           = new VideoManager              (app, this);
    _mavlinkLogManager      = new MAVLinkLogManager         (app, this);
    _adsbVehicleManager     = new ADSBVehicleManager        (app, this);
#if defined(QGC_ENABLE_PAIRING)
    _pairingManager         = new PairingManager            (app, this);
#endif
    //-- Airmap Manager
    //-- This should be "pluggable" so an arbitrary AirSpace manager can be used
    //-- For now, we instantiate the one and only AirMap provider
#if defined(QGC_AIRMAP_ENABLED)
    _airspaceManager        = new AirMapManager             (app, this);
#else
    _airspaceManager        = new AirspaceManager           (app, this);
#endif
#if defined(QGC_GST_TAISYNC_ENABLED)
    _taisyncManager         = new TaisyncManager            (app, this);
#endif
#if defined(QGC_GST_MICROHARD_ENABLED)
    _microhardManager       = new MicrohardManager          (app, this);
#endif
}
 
void QGCToolbox::setChildToolboxes(void)
{
    // SettingsManager must be first so settings are available to any subsequent tools
    _settingsManager->setToolbox(this);
    _corePlugin->setToolbox(this);
    _audioOutput->setToolbox(this);
    _factSystem->setToolbox(this);
    _firmwarePluginManager->setToolbox(this);
#ifndef __mobile__
    _gpsManager->setToolbox(this);
#endif
    _imageProvider->setToolbox(this);
    _joystickManager->setToolbox(this);
    _linkManager->setToolbox(this);
    _mavlinkProtocol->setToolbox(this);
    _missionCommandTree->setToolbox(this);
    _multiVehicleManager->setToolbox(this);
    _mapEngineManager->setToolbox(this);
    _uasMessageHandler->setToolbox(this);
    _followMe->setToolbox(this);
    _qgcPositionManager->setToolbox(this);
    _videoManager->setToolbox(this);
    _mavlinkLogManager->setToolbox(this);
    _airspaceManager->setToolbox(this);
    _adsbVehicleManager->setToolbox(this);
#if defined(QGC_GST_TAISYNC_ENABLED)
    _taisyncManager->setToolbox(this);
#endif
#if defined(QGC_GST_MICROHARD_ENABLED)
    _microhardManager->setToolbox(this);
#endif
#if defined(QGC_ENABLE_PAIRING)
    _pairingManager->setToolbox(this);
#endif
}
 
void QGCToolbox::_scanAndLoadPlugins(QGCApplication* app)
{
#if defined (QGC_CUSTOM_BUILD)
    //-- Create custom plugin (Static)
    _corePlugin = (QGCCorePlugin*) new CUSTOMCLASS(app, app->toolbox());
    if(_corePlugin) {
        return;
    }
#endif
    //-- No plugins found, use default instance
    _corePlugin = new QGCCorePlugin(app, app->toolbox());
}

在前端获取后端类的属性的总借口即为QGroundControl，例如

property var   _vehicle:          QGroundControl.multiVehicleManager.getVehicleById(1)

在功能类中向获取其他功能类的属性即使用qgcApp()->toolbox()，如果功能类继承了QGCTool则直接可以使用_toolbox->...即可。

_mavlink = qgcApp()->toolbox()->mavlinkProtocol();
_mavlinkProtocol =           _toolbox->mavlinkProtocol();

其实只要理解这几个总文件之间的关系后，就理解了QGC的整体结构。_app和_toolbox是QGC整个软件的总接口，_app和_toolbox都在QGCApplication类中，然后所有功能类都在QGCToolBox类中新建，想要获取功能类的属性就需要通过_toolbox。然后QGroundControlQmlGlobal中通过指针地址获取到了所有功能类，然后又通过Q_PROPERTY将类以属性的形式开放给前端，再加上单例模式直接在前端import QGroundControl即可获取到后端属性。这样即完成了前后端数据连通，也解决了各个功能类之间的属性获取。

以上是个人理解，很多地理解的不是太透彻，等有新的理解再更新。有错误的地方也望大佬指正，共同进步。