QFile on Android!

RenanHm

Hello.. I'm trying to open a flat TXT file on Android.

This way, with the file inside the program folder, I can read it:

    QFile file( "/data/user/0/com.digitalsof.pontofacilapp38/files/TEST.TXT" );
    if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
        return;

But this way, with the file in the Documents folder I can't read:

 QFile file( "/storage/emulated/0/Documents/TEST.TXT" );
    if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
        return;

Apparently it's an Android permissions issue.

But how to grant permission to read in Documents folder??

And the curious thing that I can save in the Documents folder. I just can't read.

I use QT 5.14.2

J.Hilk

@RenanHm

Check the answers here:

https://forum.qt.io/topic/105406/how-to-save-files-in-android-in-downloads

should not have changed since then

RenanHm

I perform the permissions check when opening the APP and before trying to open the file:

    using namespace QtAndroid;
    //SOPermission sop;
    QStringList permissions = {"android.permission.READ_EXTERNAL_STORAGE", "android.permission.WRITE_EXTERNAL_STORAGE", "android.permission.INTERNET"};
    const QHash<QString, PermissionResult> results = requestPermissionsSync(permissions);
    auto ok = true;
    auto i = 0;
    while (ok && i< permissions.size()) {
        if (!results.contains(permissions[i]) || results[permissions[i]] == PermissionResult::Denied) {
            qCritical() << "Couldn't get permission: " << permissions[i];
            ok = false;
            --i;
        }
        ++i;
    }
    return ok;

But without success. The problem continues. Any idea?

ekkescorner

@RenanHm probably you're dealing with SDK 30+?
you can try FileDialog to see if you get access there.
FileDialog should open the native Android FileDialog

FileDialog
        {
            id: importFileDialog
            title: "Select a file to import"
            selectExisting: true
            selectFolder: false
            selectMultiple : false
            folder: shortcuts.documents
            onAccepted: 
                console.log(myFileHelper.readFile(fileUrl))
        }

cpp:

    Q_INVOKABLE
    QString readFile(const QUrl &contentURL) const
    {
        QFile file(contentURL.toString());
        if(!file.open(QFile::ReadOnly |
                      QFile::Text))
        {
            return "Read failed";
        }
        QTextStream in(&file);
        QString myText = in.readAll();
        file.close();
        return myText;
    }

if you don't want to use FileDialog take a look at KDAB's SharedStorage: https://www.kdab.com/android-shared-storage-qt-wrapper/ and try out the example app if this library could be helpful.

also I found out that QDir and QFile on Android not only accept filePathes, but also content URIs. (not documented: https://bugreports.qt.io/browse/QTBUG-99664)

if all of this doesn't help - probably we have to wait until Qt has finalized support of Android (https://bugreports.qt.io/browse/QTBUG-98974) ScopedStorage.