USB Storage detection and file read/write.

Awadhesh Maurya

Hi,
I want to detect pen drive plugin in Qt application and file read/write to it.
Please let suggest me about it. I am using Qt4.8.

p3c0

@Awadhesh-Maurya Which OS are you targetting ? If Linux and if it has UDisks daemon running then use qdbus. Check this blog for more info.

SGaist

Hi,

To stay cross-platform your can consider the use of KDE's Solid library

Hope it helps

kevfu

@SGaist , do you know if the kde solid library is something I can use if I am planning to deploy to mac, windows and linux?

SGaist

Yes it is

GeorgePTVS

I was able to use a timer to keep looking at QDir::drives() to check for changes in the list. Works on Windows 7; I am making no claims for other platforms. Here's some code:

I call initFileSystem() from elsewhere initially.

void MyWidget::initFileSystem()
{
  if (mFileSystemModel)
    delete mFileSystemModel;
  mFileSystemModel = new QFileSystemModel(qApp);
  initListView(true);  // this just clears the view and sets its root to match the file model
  if ( !mDriveWatcherInitialized )
    initDriveWatcher();
}


void MyWidget::initDriveWatcher()
{
  bool connected = true;
  mDriveWatcherTimer = new QTimer(this);
  mDriveWatcherTimer->setInterval(DRIVE_WATCHER_TIMER_MILLISECONDS);  // e.g. 300 - 500 ms
  connected &= connect(mDriveWatcherTimer, SIGNAL(timeout()), this, SLOT(checkForDriveChanges())) != nullptr;
  mDriveWatcherTimer->start();
  mDriveWatcherInitialized = true;
}

void MyWidget::checkForDriveChanges()
{
  // skip on/near startup
  static const int NUM_TIMES_TO_SKIP_DRIVE_CHANGE_CHECK = 5;
  static int timesThrough = 0;
  if (timesThrough++ < NUM_TIMES_TO_SKIP_DRIVE_CHANGE_CHECK)
    return;

  static QFileInfoList originalFileInfoList = QDir::drives();
  QFileInfoList currentFileInfoList = QDir::drives();
  bool drivesChanged = false;
  // quick easy check
  if (currentFileInfoList.size() != originalFileInfoList.size())
  {
    drivesChanged = true;
  }
  else
  {
    // harder brute force check
    int numMatches = 0;
    foreach(QFileInfo currentFileInfo, currentFileInfoList)
    {
      foreach(QFileInfo originalFileInfo, originalFileInfoList)
      {
        if (currentFileInfo.absolutePath() == originalFileInfo.absolutePath())
        {
          numMatches++;
          break;
        }
      }  // foreach(QFileInfo originalFileInfo, originalFileInfoList)
    }  // foreach(QFileInfo currentFileInfo, currentFileInfoList)

    if (numMatches != currentFileInfoList.size())
      drivesChanged = true;
  }  // else
  if (drivesChanged)
  {
    initFileSystem();  // this is what kicks the model
    originalFileInfoList = QDir::drives();
  }
}  // void MyWidget::checkForDriveChanges()

veer

@SGaist said in USB Storage detection and file read/write.:

KDE's Solid

kindly help me to compile it please , I am facing problem to do it

SGaist

@veer hi, without any information, it's not possible to help you.