Qt failed to write external SD card on Android

Ader

When using Qt on Android, I found that the external SD card can be read but cannot be written. I applied for write permission when using it.AndroidManifest.xml has set <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

main.cpp

#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include <QtQuick/QQuickView>
#include <QQmlContext>
#include <QDebug>
#include <QFile>
#include <QtAndroid>

bool checkPermission() {
QtAndroid::PermissionResult r = QtAndroid::checkPermission("android.permission.WRITE_EXTERNAL_STORAGE");
if(r == QtAndroid::PermissionResult::Denied) {
QtAndroid::requestPermissionsSync( QStringList() << "android.permission.WRITE_EXTERNAL_STORAGE" );
r = QtAndroid::checkPermission("android.permission.WRITE_EXTERNAL_STORAGE");//READ_EXTERNAL_STORAGE
if(r == QtAndroid::PermissionResult::Denied) {
return false;
}
}
return true;
}

int main(int argc, char *argv[])
{
QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
QGuiApplication app(argc, argv);
QQmlApplicationEngine engine;
checkPermission();

const QUrl url(QStringLiteral("qrc:/main.qml"));
QObject::connect(&engine, &QQmlApplicationEngine::objectCreated,
                 &app, [url](QObject *obj, const QUrl &objUrl) {
    if (!obj && url == objUrl)
        QCoreApplication::exit(-1);
}, Qt::QueuedConnection);
engine.load(url);

QString string = findSDCardStr();
QFile* file=new QFile(string + "/test.txt");
if (file->exists()) {
    if(file->open(QIODevice::WriteOnly))
        qDebug()<<"true";
    else
       qDebug()<<"false";
}
return app.exec();

}

Ader

I found that QtAndroid setting permissions on the external SD card did not work, so I used java, but the first time I put the file in the root directory, it also prompted the file to have no permissions until I saw this https://stackoverflow. com/questions/43349110/android-write-on-external-sd-card-java-io-ioexception-permission-denied found the new folder path, and then I tried it and it can be used