[SOLVED] How to see if file is selected in list view with QFileSystemModel

mar0029

Hello!

I have created a simple file viewer. It consists of a QTreeView as the directory viewer and a QListView as the file viewer. Both views use the QFileSystemModel as their model. I want to be able to check if a folder has been selected or not in the QListView.

I've tried things like

if(ui->listView->currentIndex()) == (-1)), which gives a 'no match for operator ==' error
different connect statements that check for file types of the QFileSystemModel

I really want to be able to write an if... else... statement. The psuedocode being :
if(noFileSelected)
modalDialog for error
else
doThisOtherThing

Any tips in the right direction? I've scoured the documentation and have come up empty.

SGaist

Hi and welcome to devnet,

You can use isValid from QModelIndex

mar0029

@SGaist
Thank you for your reply!! A quick question:
How would I go about implementing QModelIndex::isValid() ? I can't call isValid without a QModelIndex object and I can't redefine my QFileSystemModel object as a QModelIndex.

Any tips would be greatly appreciated.

raf924

@mar0029 Get the index with the index()method : http://doc.qt.io/qt-5/qfilesystemmodel.html#index-1 I think

mar0029

@raf924

Thank you for your reply!

I am able to use "myModelIndex.isValid()" as a boolean value now but only if I set

myModelIndex = myModel->index(myFilePath,0)

where in index(), QString myFilePath = "C:/" and the integer is an arbitrary column value.
I know I need myFilePath to be that of the index value in my signal function void QAbstractItemView::clicked(const QModelIndex & index). Question is, how do I go about doing that?

raf924

@mar0029 I'm not sure what you mean. This ?

QString QFileSystemModel::filePath(const QModelIndex & index) const
Returns the path of the item stored in the model under the index given.

SGaist

Before going further, can you post the code you are currently using ? That way we are all on the same page about what you are trying to achieve and how.

mar0029

@raf924
@SGaist
Here are the two functions of concern.

void MainWindow::on_dirView_clicked(const QModelIndex &index)
{
     QString sPath = dirModel->fileInfo(index).absoluteFilePath();
     ui->listView->setRootIndex(listModel->setRootPath(sPath));
}

void MainWindow::loadButton()
{
	//index = new QModelIndex(this);

	//qDebug() << "Load Button Test" << endl; //testing purposes.

   // index = new QModelIndex(this);

 	//QString sPath = listModel->filePath(index);

	QString sPath = "C:/";

	QModelIndex test = listModel->index(sPath,0);

      if (test.isValid() == false)
    {
        QDialog* loadMessage = new QDialog;
        loadMessage->setFixedSize(250,150);

        QVBoxLayout *vertLayout = new QVBoxLayout;

        QLabel *messageLabel = new QLabel("No File was selected. Please select a .dat file.");
        
        QPushButton *messageOKButton = new QPushButton("OK");

        vertLayout->addWidget(messageLabel);
        vertLayout->addWidget(messageOKButton);

        loadMessage->setLayout(vertLayout);
        connect(messageOKButton, SIGNAL(clicked(bool)), loadMessage, SLOT(accept()));
        loadMessage->exec();
    }
      else
      {
          ui->mpfTAB->setCurrentIndex(1);
      }
}

aside: Thank you for your help!!
edit(s): figured out formatting

SGaist

You have a memory leak, you're not deleting loadMessage.

So if I understand you correctly, when you call loadButton, you would like to act on the currently selected item from listModel, right ?

mar0029

@SGaist

Whoops. I'll do a

connect(loadMessage, SIGNAL(finished(int)), loadMessage, SLOT(deleteLater)));

to clean up my leak.

That is correct. Really, there should never be an invalid file type because I specified the file type in MainWindow with listModel->setNameFilters(matFilters); where matFilters is specified as .dat. So all I really need to see is if any selection has been made in listView.

SGaist

Then you use QListView::selectedIndexes to retrieve the current selection and work with that directly

SGaist

By the way setting the Qt::WA_DeleteOnClose attribute on the widget will be cleaner

mar0029

@SGaist
Thank you so much for your replies.
After much ado, we've solved the problem!

I had to do

QModelIndexList test = ui->listView->selectionModel()->selectedIndexes();
if(test.empty() == true)
{
...
}

Thank you again everyone!

SGaist

You're welcome !

By the way, now you can use the "Topic Tool" button to mark the thread as solved, it keeps the things cleaner :)