QFileDialog::getOpenFileName doesn't set the initial directory on Mac OS 10.8 Mountain Lion

Got the same issue with Qt5.2.0 on Mavericks... I found a work around: append a dummy file name to the directory you want to select. However, be sure not to do this on Windows because the user will see it.

QString dir = "/Users/myuser/Desktop";
#if defined(__APPLE__)
dir += "/MyFile.txt";
#endif
fn = QFileDialog::getOpenFileName(this, "Select File", dir);

Also, for those like me that instantiate a file dialog because they need more options you can also do:

QFileDialog fileDialog(this, "Select File");
#if defined(__APPLE__)
fileDialog.selectFile(dir + "/MyFile.txt");
#else
fileDialog.setDirectory(dir);
#endif
...

This is a bug in Qt that is reportedly fixed in Qt 5.0.1 and Qt 4.8.4 (though it seems that it still reproducible in 4.8.4 by people (myself included)).

This bug has been reported in JIRA as QTBUG-20771, QTBUG-28161 and finally QTBUG-35779 (which appears to have finally fully resolved the issue in Qt 5.2.1). Here is a link to the patch in Gerrit.