4 files changed, 47 insertions, 23 deletions
diff --git a/src/plugins/platforms/android/qandroidplatformopenglcontext.cpp b/src/plugins/platforms/android/qandroidplatformopenglcontext.cpp
index faccf8b1173..fbfbb625dd2 100644
--- a/src/plugins/platforms/android/qandroidplatformopenglcontext.cpp
+++ b/src/plugins/platforms/android/qandroidplatformopenglcontext.cpp
@@ -22,19 +22,41 @@ QAndroidPlatformOpenGLContext::QAndroidPlatformOpenGLContext(const QSurfaceForma
 
 void QAndroidPlatformOpenGLContext::swapBuffers(QPlatformSurface *surface)
 {
-    if (surface->surface()->surfaceClass() == QSurface::Window &&
-            static_cast<QAndroidPlatformOpenGLWindow *>(surface)->checkNativeSurface(eglConfig())) {
-        QEGLPlatformContext::makeCurrent(surface);
+    if (surface->surface()->surfaceClass() != QSurface::Window) {
+        QEGLPlatformContext::swapBuffers(surface);
+        return;
     }
 
+    QAndroidPlatformOpenGLWindow *window = static_cast<QAndroidPlatformOpenGLWindow *>(surface);
+    // Since QEGLPlatformContext::makeCurrent() and QEGLPlatformContext::swapBuffers()
+    // will be using the eglSurface of the window, which wraps the Android Surface, we
+    // need to lock here to make sure we don't end up using a Surface already destroyed
+    // by Android
+    window->lockSurface();
+
+    if (window->checkNativeSurface(eglConfig())) {
+        // Call base class implementation directly since we are already locked
+        QEGLPlatformContext::makeCurrent(surface);
+    }
     QEGLPlatformContext::swapBuffers(surface);
+
+    window->unlockSurface();
 }
 
 bool QAndroidPlatformOpenGLContext::makeCurrent(QPlatformSurface *surface)
 {
-    return QEGLPlatformContext::makeCurrent(surface);
+    if (surface->surface()->surfaceClass() != QSurface::Window)
+        return QEGLPlatformContext::makeCurrent(surface);
+
+    QAndroidPlatformOpenGLWindow *window = static_cast<QAndroidPlatformOpenGLWindow *>(surface);
+    window->lockSurface();
+    const bool ok = QEGLPlatformContext::makeCurrent(surface);
+    window->unlockSurface();
+    return ok;
 }
 
+// Called from inside QEGLPlatformContext::swapBuffers() and QEGLPlatformContext::makeCurrent(),
+// already locked
 EGLSurface QAndroidPlatformOpenGLContext::eglSurfaceForPlatformSurface(QPlatformSurface *surface)
 {
     if (surface->surface()->surfaceClass() == QSurface::Window) {
diff --git a/src/plugins/platforms/android/qandroidplatformopenglwindow.cpp b/src/plugins/platforms/android/qandroidplatformopenglwindow.cpp
index c052b004131..77b486cce88 100644
--- a/src/plugins/platforms/android/qandroidplatformopenglwindow.cpp
+++ b/src/plugins/platforms/android/qandroidplatformopenglwindow.cpp
@@ -50,6 +50,8 @@ void QAndroidPlatformOpenGLWindow::setGeometry(const QRect &rect)
     }
 }
 
+// Called by QAndroidPlatformOpenGLContext::eglSurfaceForPlatformSurface(),
+// surface is already locked when calling this
 EGLSurface QAndroidPlatformOpenGLWindow::eglSurface(EGLConfig config)
 {
     if (QAndroidEventDispatcherStopper::stopped() ||
@@ -57,8 +59,6 @@ EGLSurface QAndroidPlatformOpenGLWindow::eglSurface(EGLConfig config)
         return m_eglSurface;
     }
 
-    QMutexLocker lock(&m_surfaceMutex);
-
     if (!m_surfaceCreated) {
         AndroidDeadlockProtector protector;
         if (!protector.acquire())
@@ -69,25 +69,24 @@ EGLSurface QAndroidPlatformOpenGLWindow::eglSurface(EGLConfig config)
     }
 
     if (m_eglSurface == EGL_NO_SURFACE) {
-        m_surfaceMutex.unlock();
         checkNativeSurface(config);
-        m_surfaceMutex.lock();
     }
     return m_eglSurface;
 }
 
+// Only called by eglSurface() and QAndroidPlatformOpenGLContext::swapBuffers(),
+// m_surfaceMutex already locked
 bool QAndroidPlatformOpenGLWindow::checkNativeSurface(EGLConfig config)
 {
-    QMutexLocker lock(&m_surfaceMutex);
+    // Either no surface created, or the m_eglSurface already wraps the active Surface
+    // -> makeCurrent is NOT needed.
     if (!m_surfaceCreated || !m_androidSurfaceObject.isValid())
-        return false; // makeCurrent is NOT needed.
+        return false;
 
     createEgl(config);
 
-    // we've create another surface, the window should be repainted
-    QRect availableGeometry = screen()->availableGeometry();
-    if (geometry().width() > 0 && geometry().height() > 0 && availableGeometry.width() > 0 && availableGeometry.height() > 0)
-        QWindowSystemInterface::handleExposeEvent(window(), QRegion(QRect(QPoint(), geometry().size())));
+    // we've created another Surface, the window should be repainted
+    sendExpose();
     return true; // makeCurrent is needed!
 }
 
diff --git a/src/plugins/platforms/android/qandroidplatformwindow.cpp b/src/plugins/platforms/android/qandroidplatformwindow.cpp
index e86e617ca3e..7f43f175079 100644
--- a/src/plugins/platforms/android/qandroidplatformwindow.cpp
+++ b/src/plugins/platforms/android/qandroidplatformwindow.cpp
@@ -304,14 +304,12 @@ void QAndroidPlatformWindow::onSurfaceChanged(QtJniTypes::Surface surface)
 {
     lockSurface();
     m_androidSurfaceObject = surface;
-    if (m_androidSurfaceObject.isValid()) // wait until we have a valid surface to draw into
-         m_surfaceWaitCondition.wakeOne();
-    unlockSurface();
-
     if (m_androidSurfaceObject.isValid()) {
-        // repaint the window, when we have a valid surface
-        sendExpose();
+        // wait until we have a valid surface to draw into
+        m_surfaceWaitCondition.wakeOne();
     }
+
+    unlockSurface();
 }
 
 void QAndroidPlatformWindow::sendExpose() const
diff --git a/src/plugins/platforms/android/qandroidplatformwindow.h b/src/plugins/platforms/android/qandroidplatformwindow.h
index 221b98fce55..e493875beef 100644
--- a/src/plugins/platforms/android/qandroidplatformwindow.h
+++ b/src/plugins/platforms/android/qandroidplatformwindow.h
@@ -67,10 +67,11 @@ public:
     static bool registerNatives(QJniEnvironment &env);
     void onSurfaceChanged(QtJniTypes::Surface surface);
 
-protected:
-    void setGeometry(const QRect &rect) override;
     void lockSurface() { m_surfaceMutex.lock(); }
     void unlockSurface() { m_surfaceMutex.unlock(); }
+
+protected:
+    void setGeometry(const QRect &rect) override;
     void createSurface();
     void destroySurface();
     void sendExpose() const;
@@ -85,7 +86,11 @@ protected:
     QtJniTypes::QtWindow m_nativeQtWindow;
     SurfaceContainer m_surfaceContainerType = SurfaceContainer::SurfaceView;
     QtJniTypes::QtWindow m_nativeParentQtWindow;
-    // The Android Surface, accessed from multiple threads, guarded by m_surfaceMutex
+    // The Android Surface, accessed from multiple threads, guarded by m_surfaceMutex.
+    // If the window is using QtSurface, which is a SurfaceView subclass, this Surface will be
+    // automatically created by Android when QtSurface is in a layout and visible. If the
+    // QtSurface is detached or hidden (app goes to background), Android will automatically
+    // destroy the Surface.
     QtJniTypes::Surface m_androidSurfaceObject;
     QWaitCondition m_surfaceWaitCondition;
     bool m_surfaceCreated = false;