QFileDialog Class

Detailed Description

The QFileDialog class enables a user to traverse the file system in order to select one or many files or a directory.

The easiest way to create a QFileDialog is to use the static functions.

 fileName = QFileDialog::getOpenFileName(this,
     tr("Open Image"), "/home/jana", tr("Image Files (*.png *.jpg *.bmp)"));

In the above example, a modal QFileDialog is created using a static function. The dialog initially displays the contents of the "/home/jana" directory, and displays files matching the patterns given in the string "Image Files (*.png *.jpg *.bmp)". The parent of the file dialog is set to this, and the window title is set to "Open Image".

If you want to use multiple filters, separate each one with two semicolons. For example:

 "Images (*.png *.xpm *.jpg);;Text files (*.txt);;XML files (*.xml)"

You can create your own QFileDialog without using the static functions. By calling setFileMode(), you can specify what the user must select in the dialog:

 QFileDialog dialog(this);
 dialog.setFileMode(QFileDialog::AnyFile);

In the above example, the mode of the file dialog is set to AnyFile, meaning that the user can select any file, or even specify a file that doesn't exist. This mode is useful for creating a "Save As" file dialog. Use ExistingFile if the user must select an existing file, or Directory if only a directory may be selected. See the QFileDialog::FileMode enum for the complete list of modes.

The fileMode property contains the mode of operation for the dialog; this indicates what types of objects the user is expected to select. Use setNameFilter() to set the dialog's file filter. For example:

 dialog.setNameFilter(tr("Images (*.png *.xpm *.jpg)"));

In the above example, the filter is set to "Images (*.png *.xpm *.jpg)", this means that only files with the extension png, xpm, or jpg will be shown in the QFileDialog. You can apply several filters by using setNameFilters(). Use selectNameFilter() to select one of the filters you've given as the file dialog's default filter.

The file dialog has two view modes: List and Detail. List presents the contents of the current directory as a list of file and directory names. Detail also displays a list of file and directory names, but provides additional information alongside each name, such as the file size and modification date. Set the mode with setViewMode():

 dialog.setViewMode(QFileDialog::Detail);

The last important function you will need to use when creating your own file dialog is selectedFiles().

 QStringList fileNames;
 if (dialog.exec())
     fileNames = dialog.selectedFiles();

In the above example, a modal file dialog is created and shown. If the user clicked OK, the file they selected is put in fileName.

The dialog's working directory can be set with setDirectory(). Each file in the current directory can be selected using the selectFile() function.

The Standard Dialogs example shows how to use QFileDialog as well as other built-in Qt dialogs.

By default, a platform-native file dialog will be used if the platform has one. In that case, the widgets which would otherwise be used to construct the dialog will not be instantiated, so related accessors such as layout() and itemDelegate() will return null. Also, not all platforms show file dialogs with a title bar, so be aware that the caption text might not be visible to the user. You can set the DontUseNativeDialog option to ensure that the widget-based implementation will be used instead of the native dialog.