remotecontrolledcar example: Modernize the code

Also remove unused crashed() signal.

Task-number: QTBUG-111366
Pick-to: 6.5
Change-Id: Ia23552a6396c324c7591643afaa634879a2c185e
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

examples/dbus/remotecontrolledcar/car/car.cpp

@@ -3,18 +3,17 @@
 
 #include "car.h"
 #include <QtWidgets/QtWidgets>
-#include <qmath.h>
+#include <cmath>
 
 QRectF Car::boundingRect() const
 {
     return QRectF(-35, -81, 70, 115);
 }
 
-Car::Car() : color(Qt::green), wheelsAngle(0), speed(0)
+Car::Car()
 {
     startTimer(1000 / 33);
-    setFlag(QGraphicsItem::ItemIsMovable, true);
-    setFlag(QGraphicsItem::ItemIsFocusable, true);
+    setFlags(ItemIsMovable | ItemIsFocusable);
 }
 
 void Car::accelerate()
@@ -87,7 +86,7 @@ void Car::timerEvent(QTimerEvent *event)
 
     const qreal axelDistance = 54;
     qreal wheelsAngleRads = qDegreesToRadians(wheelsAngle);
-    qreal turnDistance = ::cos(wheelsAngleRads) * axelDistance * 2;
+    qreal turnDistance = std::cos(wheelsAngleRads) * axelDistance * 2;
     qreal turnRateRads = wheelsAngleRads / turnDistance;  // rough estimate
     qreal turnRate = qRadiansToDegrees(turnRateRads);
     qreal rotation = speed * turnRate;

examples/dbus/remotecontrolledcar/car/car.h

@@ -12,7 +12,7 @@ class Car : public QGraphicsObject
     Q_OBJECT
 public:
     Car();
-    QRectF boundingRect() const;
+    QRectF boundingRect() const override;
 
 public slots:
     void accelerate();
@@ -20,17 +20,15 @@ public slots:
     void turnLeft();
     void turnRight();
 
-signals:
-    void crashed();
-
 protected:
-    void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget = nullptr);
-    void timerEvent(QTimerEvent *event);
+    void paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
+               QWidget *widget = nullptr) override;
+    void timerEvent(QTimerEvent *event) override;
 
 private:
-    QBrush color;
-    qreal wheelsAngle; // used when applying rotation
-    qreal speed; // delta movement along the body axis
+    QBrush color = Qt::green;
+    qreal wheelsAngle = 0; // used when applying rotation
+    qreal speed = 0; // delta movement along the body axis
 };
 
 #endif // CAR_H

examples/dbus/remotecontrolledcar/car/main.cpp

@@ -16,7 +16,7 @@ int main(int argc, char *argv[])
     scene.setSceneRect(-500, -500, 1000, 1000);
     scene.setItemIndexMethod(QGraphicsScene::NoIndex);
 
-    Car *car = new Car();
+    auto car = new Car();
     scene.addItem(car);
 
     QGraphicsView view(&scene);
@@ -27,7 +27,7 @@ int main(int argc, char *argv[])
     view.show();
 
     new CarInterfaceAdaptor(car);
-    QDBusConnection connection = QDBusConnection::sessionBus();
+    auto connection = QDBusConnection::sessionBus();
     connection.registerObject("/Car", car);
     connection.registerService("org.example.CarExample");
 

examples/dbus/remotecontrolledcar/common/car.xml

@@ -6,6 +6,5 @@
 		<method name="decelerate"/>
 		<method name="turnLeft"/>
 		<method name="turnRight"/>
-		<signal name="crashed"/>
 	</interface>
-</node>
+</node>

examples/dbus/remotecontrolledcar/controller/controller.cpp

@@ -1,45 +1,25 @@
 // Copyright (C) 2016 The Qt Company Ltd.
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
 
-#include <QtWidgets>
-
 #include "controller.h"
-#include "car_interface.h"
 
-Controller::Controller(QWidget *parent)
-    : QWidget(parent)
+using org::example::Examples::CarInterface;
+
+Controller::Controller(QWidget *parent) : QWidget(parent)
 {
     ui.setupUi(this);
-    car = new org::example::Examples::CarInterface("org.example.CarExample", "/Car",
-                           QDBusConnection::sessionBus(), this);
+    car = new CarInterface("org.example.CarExample", "/Car", QDBusConnection::sessionBus(), this);
+
+    connect(ui.accelerate, &QPushButton::clicked, car, &CarInterface::accelerate);
+    connect(ui.decelerate, &QPushButton::clicked, car, &CarInterface::decelerate);
+    connect(ui.left, &QPushButton::clicked, car, &CarInterface::turnLeft);
+    connect(ui.right, &QPushButton::clicked, car, &CarInterface::turnRight);
+
     startTimer(1000);
 }
 
 void Controller::timerEvent(QTimerEvent *event)
 {
     Q_UNUSED(event);
-    if (car->isValid())
-        ui.label->setText("connected");
-    else
-        ui.label->setText("disconnected");
-}
-
-void Controller::on_accelerate_clicked()
-{
-    car->accelerate();
-}
-
-void Controller::on_decelerate_clicked()
-{
-    car->decelerate();
-}
-
-void Controller::on_left_clicked()
-{
-    car->turnLeft();
-}
-
-void Controller::on_right_clicked()
-{
-    car->turnRight();
+    ui.label->setText(car->isValid() ? tr("connected") : tr("disconnected"));
 }

examples/dbus/remotecontrolledcar/controller/controller.h

@@ -12,16 +12,10 @@ class Controller : public QWidget
     Q_OBJECT
 
 public:
-    Controller(QWidget *parent = nullptr);
+    explicit Controller(QWidget *parent = nullptr);
 
 protected:
-    void timerEvent(QTimerEvent *event);
-
-private slots:
-    void on_accelerate_clicked();
-    void on_decelerate_clicked();
-    void on_left_clicked();
-    void on_right_clicked();
+    void timerEvent(QTimerEvent *event) override;
 
 private:
     Ui::Controller ui;