Add logic for moving the platform

src/mainwindow.cpp

@@ -2,8 +2,9 @@
 #include "./ui_mainwindow.h"
 #include <QDebug>
 #include <memory>
+#include <qnamespace.h>
 
-MainWindow::MainWindow(QWidget* parent) : QMainWindow(parent), ui(new Ui::MainWindow) {
+MainWindow::MainWindow(QWidget* parent) : QMainWindow(parent), ui(new Ui::MainWindow), leftArrowPressed{false}, rightArrowPressed{false} {
     ui->setupUi(this);
 
     platform = std::make_shared<Platform>(this);
@@ -43,3 +44,17 @@ void MainWindow::onDeleteBall(Ball* ball) {
         }
     }
 }
+
+void MainWindow::keyPressEvent(QKeyEvent* event) {
+    switch (event->key()) {
+        case Qt::Key_Left: leftArrowPressed = true; break;
+        case Qt::Key_Right: rightArrowPressed = true; break;
+    }
+}
+
+void MainWindow::keyReleaseEvent(QKeyEvent* event) {
+    switch (event->key()) {
+        case Qt::Key_Left: leftArrowPressed = false; break;
+        case Qt::Key_Right: rightArrowPressed = false; break;
+    }
+}

src/mainwindow.h

@@ -3,7 +3,10 @@
 
 #include "ball.h"
 #include "platform.h"
+#include <QKeyEvent>
 #include <QMainWindow>
+#include <QWidget>
+#include <qevent.h>
 
 QT_BEGIN_NAMESPACE
 namespace Ui {
@@ -18,12 +21,18 @@ class MainWindow : public QMainWindow {
     MainWindow(QWidget* parent = nullptr);
     ~MainWindow();
 
+    bool leftArrowPressed;
+    bool rightArrowPressed;
+
   private slots:
     void onDeleteBall(Ball* ball); // Slot to handle the ball deletion
 
   protected:
     virtual void paintEvent(QPaintEvent*) override;
 
+    void keyPressEvent(QKeyEvent* event) override;
+    void keyReleaseEvent(QKeyEvent* event) override;
+
   private:
     Ui::MainWindow* ui;
     QList<std::shared_ptr<Ball>> balls;

src/platform.cpp

@@ -1,5 +1,7 @@
 #include "platform.h"
+#include "mainwindow.h"
 #include <QDebug>
+#include <qapplication.h>
 
 #define TICK_SPEED 15
 #define PLATFORM_WIDTH 100
@@ -7,7 +9,7 @@
 #define PLATFORM_MARGIN_BOTTOM 80
 #define SPEED 5.0
 
-Platform::Platform(QWidget* parent) : m_parent{parent} {
+Platform::Platform(MainWindow* parent) : m_parent{parent} {
     QRect rct = parent->rect();
 
     m_x = rand() % (rct.width() - PLATFORM_WIDTH);
@@ -23,4 +25,12 @@ void Platform::draw(QPainter& painter) {
 
 void Platform::timerEvent(QTimerEvent*) {
     m_parent->update();
+
+    int direction = 0;
+    if (m_parent->leftArrowPressed && !m_parent->rightArrowPressed)
+        direction = -1;
+    else if (m_parent->rightArrowPressed && !m_parent->leftArrowPressed)
+        direction = 1;
+
+    m_x += direction * SPEED;
 }

src/platform.h

@@ -5,11 +5,16 @@
 #include <QTimer>
 #include <QWidget>
 
+// Forward declaration, avoiding circular import of mainwindow.h
+// (this probably isn't the best way to handle this, but I wasn't
+// sure how else to do it.)
+class MainWindow;
+
 class Platform : public QTimer {
     Q_OBJECT
 
   public:
-    Platform(QWidget* parent);
+    Platform(MainWindow* parent);
 
     void draw(QPainter& painter);
 
@@ -17,7 +22,7 @@ class Platform : public QTimer {
     virtual void timerEvent(QTimerEvent*) override;
 
   private:
-    QWidget* m_parent;
+    MainWindow* m_parent;
     double m_x;
     double m_y;
 };