Recording audio works on windows but not on android

Desard

Hey guys, i want to record and save audio in a file. Here is the code is use:
audioRecorder.h

private: QDir folder;

audioRecorder.cpp

QAudioEncoderSettings audioSettings;
audioSettings.setCodec("audio/pcm");
audioSettings.setQuality(QMultimedia::HighQuality);

audioRecorder.setEncodingSettings(audioSettings);
folder = QStandardPaths::writableLocation(QStandardPaths::DocumentsLocation);

QString qdir = folder.path();
qdir.append(QString("/test.wav"));

audioRecorder.setOutputLocation(QUrl::fromLocalFile(qdir));

void AudioRecorder::start()
{
    audioRecorder.record();
}

void AudioRecorder::stop()
{
    audioRecorder.stop();
}

void AudioRecorder::play()
{
    QString qdir = folder.path();
    qdir.append("/test.wav");
    mediaPlayer.setMedia(QUrl::fromLocalFile(qdir));
    mediaPlayer.setVolume(20);
    mediaPlayer.play();
}

Everything works as intended on windows . On android it looks like the mendiaRecorder is not able to create the file. I tried to open the file, but it doesnst exit after calling audioRecorder.record() and audioRecorder.stop().

I then tried to create the file manually:

folder = QStandardPaths::writableLocation(QStandardPaths::DocumentsLocation);

QString qdir = folder.path();
qdir.append(QString("/test.wav"));
QFile file(qdir);

if (file.exists())
  file.remove();

qDebug() << "file exists:  " << file.exists();

if (!file.exists()) {

    if (!folder.exists()) {
        folder.mkpath(folder.path());
    }

    file.open(QIODevice::WriteOnly);
    file.write("Hello World");
    file.close();
}
if (file.exists()) {
    qDebug() << "file exists:  " << file.exists();
    file.open(QIODevice::ReadOnly);
    QByteArray data=file.readAll();
    qWarning("file data=%s",data.constData());
    file.close();
}

QStandardPaths::writableLocation(QStandardPaths::DocumentsLocation) gives back:
/storage/0/emulated/Documents

file.open(QIODevice::ReadOnly) gives back:
QIODevice::write (QFile, "/storage/emulated/0/Documents/transmission.wav"): device not open

Looks like i am not able to create a file nor is the mediaRecorder. I also tried GenericDataLocation and other Locations.
I get D MediaRecorder: no match storage volume found! if i use HomeLocation

Infos:
Htc one M8 (Andoird 6.0)
Permissions set: audio_record, read_external_storage, write_external_storage
target-SDK = API 26, Android 8.0
min-SDK = API 16, 4.1

SGaist

Hi and welcome to devnet,

What version of Qt are you using ?

operamint

I have basically the exact same problem. Qt 5.9.4, Galaxy S7, Android 7.0. Can't make subfolders, or write files directly in the docs folder. Docs folder shows: "/storage/emulated/0/Documents". This folder does exist, though.

folder = QStandardPaths::writableLocation(QStandardPaths::DocumentsLocation) + "/subdir";
QDir dir(folder);
if (!dir.exists()) {
    bool ok = dir.mkpath(".");
    qDebug() << "mkdir: " << ok;    // <-- false
}

SGaist

What if you use QStandardPaths::MusicLocation ?

operamint

@SGaist said in Recording audio works on windows but not on android:

What if you use QStandardPaths::MusicLocation ?

Nope. Gives "/storage/emulated/0/Music". Anything under /storage/emulated/0 is write protected. However QStandardPaths::DataLocation --> "/data/user/0/<package name>/files" is writable, but I want it in the shared area. Obviously many other apps can write to that location, e.g. "Ol File Manager". Btw, I'm now on Qt 5.10.0.

operamint

Figured it out. Make pop up request for write permission if it doesn't have it in Qt 5.10:

# .pro file
android {
    QT += androidextras
}

#include <QtAndroidExtras/QtAndroid>
...
QtAndroid::requestPermissionsSync( QStringList() << "android.permission.WRITE_EXTERNAL_STORAGE" );

Desard

This post is deleted!