Disconnect immediately when the app is put to sleep (or sent to background)

README.md

@@ -3,9 +3,9 @@
 
 ## About
 
-Launch [Qt Design Studio](https://www.qt.io/ui-design-tools) projects in your Android device. The viewer that helps you do with [Qt for Android](https://doc.qt.io/qt-6/android.html).
+Launch [Qt Design Studio](https://www.qt.io/ui-design-tools) projects in your Android device in seconds. Qt UI Viewer is a simple app that allows you to view your Qt Design Studio projects on your Android device. It's a great tool for designers and developers to preview their designs on a real device.
 
-Qt UI Viewer works with minimum Android 11 (API level 30).
+Qt UI Viewer is built with [Qt for Android](https://doc.qt.io/qt-6/android.html).
 
 ## Getting the App
 
@@ -16,15 +16,14 @@ You can get the pre-built app from either [Google Play Store][google-play-link]
 * CMake 3.16 or newer
 * Qt 6.8.0 or newer
 * OpenSSL (<https://github.com/KDAB/android_openssl>)
-* Android SDK and NDK (<https://developer.android.com/studio>)
+* Android (min API 34) SDK and NDK (<https://developer.android.com/studio>)
 
 ## Code Map
 
 * cicd: GitLab pipeline files
 * resources: UI related files
 * android: Files needed for Android build system
-* src: Backend source files
-* ui: UI source files
+* src: All source files
 * 3rdparty: Required 3rd party libraries
     * qtquickdesigner-components: QML components
     * zxing-cpp: QR code decoding/encoding

src/Main.qml

@@ -61,7 +61,6 @@ Rectangle {
             Connections {
                 target: backend
                 function onConnectedChanged(isConnected) {
-                    console.log("Connected changed to", isConnected)
                     root.connected = isConnected
                 }
             }

src/backend/backend.cpp

@@ -74,6 +74,18 @@ Backend::Backend(QObject *parent)
         }
     });
 
+    connect(qApp,
+            &QGuiApplication::applicationStateChanged,
+            this,
+            [this](Qt::ApplicationState state) {
+                qDebug() << "Application state changed to" << state;
+                if (state == Qt::ApplicationState::ApplicationSuspended) {
+                    if (m_projectManager && !m_projectManager->sessionId().isEmpty())
+                        QMetaObject::invokeMethod(m_projectManager.get(), "stopProject");
+                    m_dsManager->disconnectAllDesignStudios();
+                }
+            });
+
     const QRect screenGeometry = QGuiApplication::primaryScreen()->geometry();
 
     qDebug() << "Qt Design Viewer";

src/backend/dsconnector/ds.cpp

@@ -67,6 +67,12 @@ void DesignStudio::initPingPong()
             &QWebSocket::pong,
             this,
             [this](quint64 elapsedTime, const QByteArray &) {
+                if (elapsedTime > 1000)
+                    qWarning() << "Design Studio pong is too slow:" << elapsedTime
+                               << "ms. Newtork issue?";
+                else if (elapsedTime > 500)
+                    qWarning() << "Design Studio pong is slow:" << elapsedTime << "ms";
+
                 m_pongTimer.stop();
                 m_pingTimer.start();
             });
@@ -111,6 +117,12 @@ void DesignStudio::initSocket()
             &DesignStudio::processBinaryMessage);
 }
 
+void DesignStudio::disconnect()
+{
+    m_socket->close();
+    m_socket->abort();
+}
+
 QString DesignStudio::ipv4Addr() const
 {
     return m_socket->peerAddress().toString();

src/backend/dsconnector/ds.h

@@ -13,6 +13,9 @@ class DesignStudio : public QObject
 public:
     DesignStudio(QWebSocket *socket, const QString &deviceID, QObject *parent = nullptr);
 
+    // Connection
+    void disconnect();
+
     // Getters
     QString ipv4Addr() const;
     QString id() const;

src/backend/dsconnector/dsmanager.cpp

@@ -136,3 +136,24 @@ QString DesignStudioManager::getDesignStudioIp(const QString &id) const
 
     return {};
 }
+
+bool DesignStudioManager::disconnectDesignStudio(const QString &id)
+{
+    for (const auto &designStudio : m_designStudios) {
+        if (designStudio->id() == id) {
+            qDebug() << "Disconnecting Design Studio" << id;
+            designStudio->disconnect();
+            return true;
+        }
+    }
+
+    qWarning() << "Design Studio" << id << "not found for disconnection";
+    return false;
+}
+
+void DesignStudioManager::disconnectAllDesignStudios()
+{
+    qDebug() << "Disconnecting all Design Studios";
+    for (const auto &designStudio : m_designStudios)
+        designStudio->disconnect();
+}

src/backend/dsconnector/dsmanager.h

@@ -21,6 +21,8 @@ public slots:
     void sendProjectStopped(const QString &id);
     void sendProjectLogs(const QString &id, const QString &logs);
     QString getDesignStudioIp(const QString &id) const;
+    bool disconnectDesignStudio(const QString &id);
+    void disconnectAllDesignStudios();
 
 private:
     // Network