Adding pushButton on QFileDialog

[samdol]

Hi
I tried to add a pushButton on QFileDialog by

class FileDialog : public QFileDialog
{
    QPushButton *pb;
public:
    FileDialog(QWidget *parent) : QFileDialog(parent){}

    void addWidget()
    {
        QGridLayout* mainLayout = dynamic_cast <QGridLayout*>(this->layout());
        if( !mainLayout){
            qDebug()<<"mainLayout is NULL";
        }else{

            QHBoxLayout *hbl =new QHBoxLayout(0);
            pb =new QPushButton(QString("My checkbox"));
            hbl->addWidget(pb);
            int num_rows = mainLayout->rowCount();
            qDebug()<<"num_rows: "<<num_rows;
            mainLayout->addLayout(hbl, num_rows, 0, 1, -1);
        }
    }
};

When I executed

    FileDialog *fd=new FileDialog(this);
    fd->addWidget();

I got the result,
"mainLayout is NULL"
It means I could not get the QGridLayout* by this->layout().
Is it a bug? I use Qt 5.6.2 in windows7.

[Eligijus]

Try to use http://doc.qt.io/qt-5/qobject.html#qobject_cast . Or just pass layout pointer as argument in your function.

[jsulm]

@samdol I guess the layout in a QFileDialog is not QGridLayout, that's why the cast fails.

[mtrch]

This is because QFileDialog uses native file dialog by default, you just need to turn off this behavior:

FileDialog(QWidget *parent) : QFileDialog(parent)
{
    setOption(QFileDialog::DontUseNativeDialog);
}

[samdol]

@mtrch
Thank you mtrch, That makes it return QGridLayout correctly,
but
fileName = fd->getOpenFileName(this,
tr("Open Image"), "/home/jana", tr("Image Files (*.png *.jpg *.bmp)"));
does not show any change on FileDialog.

[m.sue]

getOpenFileName is a static function. It does not care about any changes you made to fd.

You will have to do everything of the static function yourself:

fd->setWindowTitle("Open Image");
fd->setAcceptMode(QFileDialog::AcceptOpen);
fd->setDirectory("/home/jana");
fd->setFileMode(QFileDialog::ExistingFile);
fd->setViewMode(QFileDialog::Detail);
fd->setNameFilter(tr("Image Files (*.png *.jpg *.bmp)"));
if (!fd->exec())
	//cancelled
	return;
fileName=fd->selectedFiles().first();

-Michael.

[samdol]

@m.sue
Thanks. It works as expected. Can I set the style of fd to the style of the QFileDialog on executing getOpenFileName()?

[m.sue]

"style": IIRC the static function uses the native dialog, by default. If you mean that, then no (see above).