Android: fix camera preview showing black frames after restarting it.

Clear the camera preview size when stopping the preview in order to
force it to be reset when starting it again.

Task-number: QTBUG-34346
Change-Id: I0edf8d996348745b9aa7cf0790c16b6cd813b33b
Reviewed-by: Christian Stromme <christian.stromme@digia.com>

3 files changed, 13 insertions, 3 deletions

diff --git a/src/plugins/android/src/mediacapture/qandroidcamerafocuscontrol.cpp b/src/plugins/android/src/mediacapture/qandroidcamerafocuscontrol.cpp
index 899a3a499..345a29174 100644
--- a/src/plugins/android/src/mediacapture/qandroidcamerafocuscontrol.cpp
+++ b/src/plugins/android/src/mediacapture/qandroidcamerafocuscontrol.cpp
@@ -238,6 +238,10 @@ void QAndroidCameraFocusControl::updateFocusZones(QCameraFocusZone::FocusZoneSta
         return;
 
     QSize viewportSize = m_session->camera()->previewSize();
+
+    if (!viewportSize.isValid())
+        return;
+
     QSizeF focusSize(50.f / viewportSize.width(), 50.f / viewportSize.height());
     float x = qBound(qreal(0),
                      m_actualFocusPoint.x() - (focusSize.width() / 2),
diff --git a/src/plugins/android/src/mediacapture/qandroidcamerasession.cpp b/src/plugins/android/src/mediacapture/qandroidcamerasession.cpp
index 75b0c5e9b..075fe78e5 100644
--- a/src/plugins/android/src/mediacapture/qandroidcamerasession.cpp
+++ b/src/plugins/android/src/mediacapture/qandroidcamerasession.cpp
@@ -205,8 +205,11 @@ void QAndroidCameraSession::adjustViewfinderSize(const QSize &captureSize, bool
 
     QSize viewfinderResolution = m_camera->previewSize();
     const qreal aspectRatio = qreal(captureSize.width()) / qreal(captureSize.height());
-    if (qFuzzyCompare(aspectRatio, qreal(viewfinderResolution.width()) / qreal(viewfinderResolution.height())))
+    if (viewfinderResolution.isValid() &&
+            qFuzzyCompare(aspectRatio,
+                          qreal(viewfinderResolution.width()) / viewfinderResolution.height())) {
         return;
+    }
 
     QList<QSize> previewSizes = m_camera->getSupportedPreviewSizes();
     for (int i = previewSizes.count() - 1; i >= 0; --i) {
@@ -270,6 +273,7 @@ void QAndroidCameraSession::stopPreview()
     JMultimediaUtils::enableOrientationListener(false);
 
     m_camera->stopPreview();
+    m_camera->setPreviewSize(QSize());
     if (m_videoOutput)
         m_videoOutput->stop();
     m_previewStarted = false;
diff --git a/src/plugins/android/src/wrappers/jcamera.cpp b/src/plugins/android/src/wrappers/jcamera.cpp
index f858f4702..fc9b18068 100644
--- a/src/plugins/android/src/wrappers/jcamera.cpp
+++ b/src/plugins/android/src/wrappers/jcamera.cpp
@@ -261,8 +261,10 @@ void JCamera::setPreviewSize(const QSize &size)
 
     m_previewSize = size;
 
-    m_parameters.callMethod<void>("setPreviewSize", "(II)V", size.width(), size.height());
-    applyParameters();
+    if (m_previewSize.isValid()) {
+        m_parameters.callMethod<void>("setPreviewSize", "(II)V", size.width(), size.height());
+        applyParameters();
+    }
 
     emit previewSizeChanged();
 }