#include <qcamera.h>
#include <qvideowidget.h>
class CameraApp : publoc QWidget
{
    Q_OBJECT
public:
    CameraApp(QWidget* parent = 0);
    ~CameraApp(); 
public slots:
    void error(QCamera::Error);
private:
    void InitCamera();
 
private:
    QStackedWidget* m_stackedWidget;
    QCamera* m_camera;
    QVideoWidget* m_videoWidget; 
};

    QGridLayout* layout = new QGridLayout;
    layout->setSpacing(0);
    layout->setMargin(0);
 
    m_videoWidget = new QVideoWidget();
 
    QPalette black(Qt::black);
    m_stackedWidget = new QStackedWidget();
    m_stackedWidget->setPalette(black);
 
    m_stackedWidget->addWidget(m_videoWidget);
 
    m_stackedWidget->setCurrentIndex(0);
    layout->addWidget(m_stackedWidget);
 
    setLayout(layout);
 
    InitCamera();

void CameraApp::InitCamera() {
    QByteArray cameraDevice = QCamera::availableDevices()[0];
    m_camera = new QCamera(cameraDevice);
 
    connect(m_camera, SIGNAL(error(QCamera::Error)), this, SLOT(error(QCamera::Error)));
 
    m_camera->setFocusMode(QCamera::AutoFocus);
 
    m_videoWidget->setMediaObject(m_camera);
    m_videoWidget->setAspectRatioMode(QVideoWidget::KeepAspectRatio);
 
    if (m_camera->state() == QCamera::ActiveState) {
        m_camera->stop();
        }
    m_camera->start();
    }

void CameraApp::error(QCamera::Error e) {
       switch (e) {
        case QCamera::CameraError: {
            QMessageBox::warning(this, "Camera error", "General camera error");
            break;
            }
        case QCamera::NotReadyToCaptureError: {
            QMessageBox::warning(this, "Camera error", "Camera not ready to capture image");
            break;
            }
        case QCamera::InvalidRequestError: {
            QMessageBox::warning(this, "Camera error", "Invalid request");
            break;
            }
        case QCamera::ServiceMissingError: {
            QMessageBox::warning(this, "Camera error", "Service missing");
            break;
            }
        case QCamera::NotSupportedFeatureError: {
            QMessageBox::warning(this, "Camera error", "Not supported feature");
            break;
            }
        default:
            break;
        };
    }