Saving Image to Android Device - Qt6 for Android

[Fabiolamb]

Using Qt6 for Android, the following is a successful example.

Click the capture button, it will pop up a dialog to select the file location on Android, you just need to fill in the image name + image format suffix.

mainwindow.cpp

#include "mainwindow.h"

#include <QVBoxLayout>
#include <QHBoxLayout>
#include <QCamera>
#include <QMediaDevices>
#include <QImageCapture>
#include <QApplication>
#include <QStandardPaths>
#include <QFile>
#include <QDir>
#include <QDateTime>

#include <QString>
#include <QIODevice>
#include <QLabel>

#include <QFileDialog>
#include <QImage>
#include <QPainter>
#include <QDebug>

#if QT_CONFIG(permissions)
#include <QPermission>
#endif

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent),
    camera(new QCamera(QMediaDevices::defaultVideoInput())),
    imageCapture(new QImageCapture),
    viewfinder(new QVideoWidget),
    buttonGroupBox(new QGroupBox),
    buttonGridlayout(new QGridLayout),
    captureButton(new QPushButton("Capture")),
    cameraSettingButton(new QPushButton("Setting")),
    styleSwitchButton(new QPushButton("Style")),
    centralWidget(new QWidget(this)),
    layout(new QVBoxLayout(centralWidget))
{
    setCentralWidget(centralWidget);

    buttonGridlayout->addWidget(captureButton, 0, 0);
    buttonGridlayout->addWidget(cameraSettingButton, 0, 1);
    buttonGridlayout->addWidget(styleSwitchButton, 0, 2);
    buttonGroupBox->setLayout(buttonGridlayout);

    layout->addWidget(viewfinder, 1);
    layout->addWidget(buttonGroupBox, 0);

#if QT_CONFIG(permissions)
    // Camera permission
    QCameraPermission cameraPermission;
    switch (qApp->checkPermission(cameraPermission)) {
    case Qt::PermissionStatus::Undetermined:
        qApp->requestPermission(cameraPermission, this, &MainWindow::initPermissions);
        return;
    case Qt::PermissionStatus::Denied:
        qWarning("Camera permission is not granted!");
        return;
    case Qt::PermissionStatus::Granted:
        break;
    }
#endif

    init();
}

void MainWindow::initPermissions()
{
#if QT_CONFIG(permissions)
    // Camera permission
    QCameraPermission cameraPermission;
    if (qApp->checkPermission(cameraPermission) != Qt::PermissionStatus::Granted) {
        qWarning("Camera permission is not granted!");
        return;
    }
#endif
    init();
}

void MainWindow::init()
{
    captureSession.setCamera(camera);
    captureSession.setVideoOutput(viewfinder);
    captureSession.setImageCapture(imageCapture);

    connect(captureButton, &QPushButton::clicked, this, &MainWindow::captureImage);
    connect(imageCapture, &QImageCapture::imageCaptured, this, &MainWindow::onImageCaptured);

    camera->start();
}

void MainWindow::captureImage()
{
    imageCapture->captureToFile();
}

void MainWindow::onImageCaptured(int id, const QImage &image)
{
    Q_UNUSED(id);
    capturedImage = image;

    fileName = QFileDialog::getSaveFileName(this, "Save Image", "", "Images (*.png *.jpg *.bmp)");
    if (!fileName.isEmpty()) {
        int quality = 100;
        if (capturedImage.save(fileName, nullptr, quality)) {
            qDebug() << "Image saved successfully.";
        } else {
            qDebug() << "Failed to save image.";
        }
    } else {
        qDebug() << "No file selected.";
    }
}

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QCamera>
#include <QMediaDevices>
#include <QImageCapture>
#include <QMediaCaptureSession>
#include <QVideoWidget>
#include <QSlider>
#include <QPushButton>
#include <QVBoxLayout>

#include <QGroupBox>
#include <QGridLayout>

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private slots:
    void onImageCaptured(int id, const QImage &image);
    void captureImage();

private:
    void initPermissions();
    void init();

    QString filePath;
    QString fileName;

    QImage capturedImage;

    QCamera *camera;
    QImageCapture *imageCapture;
    QMediaCaptureSession captureSession;
    QVideoWidget *viewfinder;

    QGroupBox *buttonGroupBox;
    QGridLayout *buttonGridlayout;
    QPushButton *captureButton;
    QPushButton *cameraSettingButton;
    QPushButton *styleSwitchButton;

    QWidget *centralWidget;
    QVBoxLayout *layout;
};

#endif // MAINWINDOW_H