在qt中捕获摄像头画面，在ui界面上添加一个comboBox控件、label标签和两个pushButton按钮，comboBox用于显示摄像头的设备，按钮用于开启摄像头和捕获当前帧的画面，label用于显示摄像头捕获的画面。
//需要在.pro文件中加上multimedia multimediawidgets
QT += core gui multimedia multimediawidgets
//mainwindow.cpp#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QCameraImageCapture>
#include<QCameraInfo>
#include<QCameraViewfinder>MainWindow::MainWindow(QWidget *parent): QMainWindow(parent), ui(new Ui::MainWindow)
{ui->setupUi(this);//获取当前系统的摄像头设备列表const QList<QCameraInfo> cameras = QCameraInfo::availableCameras();for(const QCameraInfo &cameraInfo:cameras){qDebug()<<cameraInfo.deviceName().toLocal8Bit().data();ui->comboBox->addItem(cameraInfo.deviceName().toUtf8().data());}
}MainWindow::~MainWindow()
{delete ui;
}void MainWindow::on_pushButton_clicked()
{//创建摄像头对象（把系统中的摄像头路径给QCamera对象）camera = new QCamera(ui->comboBox->currentText().toUtf8());//创建取景器对象，也就是用于显示摄像头画面的控件，并给对象一个父指针QCameraViewfinder *viewfinder = new QCameraViewfinder(ui->label);//根据label大小设置取景器的大小viewfinder->resize(ui->label->size());//把取景器显示在ui中viewfinder->show();//绑定摄像头和摄像头画面控件camera->setViewfinder(viewfinder);//打开摄像头camera->start();//捕获图像需要初始化一个新的QCameraImageCapture对象imageCapture = new QCameraImageCapture(camera);camera->setCaptureMode(QCamera::CaptureStillImage);//绑定信号与槽函数进行保存当前帧数据connect(imageCapture,&QCameraImageCapture::imageCaptured,this,&MainWindow::ImageCaptureToShow);}void MainWindow::on_pushButton_2_clicked()
{imageCapture->capture();
}void MainWindow::ImageCaptureToShow(int id, const QImage &preview)
{qDebug()<<"buhuo";preview.save("./1.jpg");
}//mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H#include <QCamera>
#include <QCameraImageCapture>
#include <QCameraViewfinder>
#include <QMainWindow>QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACEclass MainWindow : public QMainWindow
{Q_OBJECTpublic:MainWindow(QWidget *parent = nullptr);~MainWindow();private slots:void on_pushButton_clicked();void on_pushButton_2_clicked();void ImageCaptureToShow(int id,const QImage &preview);private:Ui::MainWindow *ui;QCamera *camera;// QCameraViewfinder *viewfinder;QCameraImageCapture *imageCapture;
};
#endif // MAINWINDOW_H