How does Qt control the camera on the mac? - macos

Question

As on Windows it is useless to write, you can't get the camera screen at all.
What should I do?
Do I need to apply for permission?
Where should I put the file Info.plist?

Answer 1

In your Info.plist you should include:
<key>NSCameraUsageDescription</key>
<string>${PRODUCT_NAME} ...a description of why the camera is used by your app...</string>
Here is an example of displaying the camera input.
mainwindow.h:
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QCamera>
#include <QCameraInfo>
#include <QCameraViewfinder>
#include <QMainWindow>
QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
MainWindow(QWidget *parent = nullptr);
~MainWindow();
private:
Ui::MainWindow *ui;
QCamera *m_camera;
QList<QCameraInfo> m_cameras;
QCameraViewfinder *m_cameraViewFinder;
private:
bool checkCameraAvailability();
private slots:
void setCamera(const QCameraInfo &cameraInfo);
void on_camerSelectBox_currentTextChanged(const QString &arg1);
};
#endif // MAINWINDOW_H
mainwindow.cpp:
#include "mainwindow.h"
#include "ui_mainwindow.h"
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
, ui(new Ui::MainWindow),
m_cameraViewFinder(new QCameraViewfinder)
{
ui->setupUi(this);
// Detect Cameras
m_cameras = QCameraInfo::availableCameras();
for (const QCameraInfo &cameraInfo : m_cameras) {
ui->camerSelectBox->addItem(cameraInfo.description());
}
// Make sure there is at least one camera available, and start with the default camera as preview.
if(checkCameraAvailability()) {
setCamera(QCameraInfo::defaultCamera());
}
}
MainWindow::~MainWindow()
{
delete m_cameraViewFinder;
delete m_camera;
delete ui;
}
void MainWindow::setCamera(const QCameraInfo &cameraInfo)
{
m_camera = new QCamera(cameraInfo);
m_camera->setViewfinder(m_cameraViewFinder);
ui->previewLayout->addWidget(m_cameraViewFinder);
m_camera->start();
}
bool MainWindow::checkCameraAvailability()
{
if (QCameraInfo::availableCameras().count() > 0)
return true;
else
return false;
}
void MainWindow::on_camerSelectBox_currentTextChanged(const QString &arg1)
{
if(checkCameraAvailability()) {
for (const QCameraInfo &cameraInfo : m_cameras) {
if( cameraInfo.description() == arg1 ) {
setCamera(cameraInfo);
}
}
}
}
In you mainwindow.ui you should include:
A layout named previewLayout
A QComboBox named camerSelectBox