CODEWITHSUNDEEP
qtpyqtpyside
Frank Rueter
Frank Rueter

Reputation: 799

How to control focus of QWidgetAction's child widgets?

for my application I'm trying to put login control into a QMenu and am struggling with controlling the focus policy. This is my custom login widget:

class LoginWidget(QWidget):

    def __init__(self, parent=None):

        super(LoginWidget, self).__init__(parent)
        mainLayout = QVBoxLayout()
        layoutH = QHBoxLayout()
        nameField = QLineEdit()
        pwdField = QLineEdit()
        pwdField.setEchoMode(QLineEdit.EchoMode(2))
        btnSubmit = QPushButton('log in')
        btnSubmit.setIcon(IconCache.getIcon('login'))

        for w in (nameField, pwdField):
            layoutH.addWidget(w)
        mainLayout.addLayout(layoutH)
        mainLayout.addWidget(btnSubmit)
        self.setLayout(mainLayout)

I then add the above widget to my menu like this:

app = QApplication([])

menu = QMenu()
settingsAction = QAction('settings', menu)
loginAction = QWidgetAction(menu)
loginAction.setDefaultWidget(LoginWidget())
menu.addAction(settingsAction)    
menu.addAction(loginAction)

btn = QToolButton()
btn.setText('menu button')
btn.setMenu(menu)
btn.setPopupMode(QToolButton.InstantPopup)

btn.show()
sys.exit(app.exec_())

The problem is that when you open the menu, click into the name field to fill in the user name, then hit the tab key, focus jumps to the "settings" action rather than to the password widget inside the LoginWidget. I tried setFocusPolicy(Qt.StrongFocus) on the LoginWidget as well as it's pwdField but to no avail.

Can this be done?

Thanks in advance, frank

Upvotes: 3

Views: 5245

Answers (2)

ekhumoro
ekhumoro

Reputation: 120798

The QMenu has special handling for Tab / Backtab, which effectively converts them into Up / Down arrow key presses.

However, the real source of the problematic behaviour is the focusNextPrevChild method, which keeps forcing the focus back to the menu. Fortunately, this method is virtual, so it can be overridden in a subclass, like so:

class Menu(QtGui.QMenu):
    def focusNextPrevChild(self, next):
        return QtGui.QWidget.focusNextPrevChild(self, next)

This will restore normal tabbing between child widgets.

To also enable keyboard navigation from child widgets back to normal menu items, make sure the LoginWidget has a focus proxy, like so:

class LoginWidget(QtGui.QWidget):
    def __init__(self, parent=None):
        ...
        self.setFocusPolicy(QtCore.Qt.TabFocus)
        self.setFocusProxy(nameField)

Upvotes: 1

phyatt
phyatt

Reputation: 19152

http://qt-project.org/doc/qt-4.8/qwidget.html#setTabOrder

http://qt-project.org/doc/qt-4.8/focus.html#tab-or-shift-tab

Tab or Shift+Tab

Pressing Tab is by far the most common way to move focus using the keyboard. (Sometimes in data-entry applications Enter does the same as Tab; this can easily be achieved in Qt by implementing an event filter.)

Pressing Tab, in all window systems in common use today, moves the keyboard focus to the next widget in a circular per-window list. Tab moves focus along the circular list in one direction, Shift+Tab in the other. The order in which Tab presses move from widget to widget is called the tab order.

You can customize the tab order using QWidget::setTabOrder(). (If you don't, Tab generally moves focus in the order of widget construction.) Qt Designer provides a means of visually changing the tab order.

Since pressing Tab is so common, most widgets that can have focus should support tab focus. The major exception is widgets that are rarely used, and where there is some keyboard accelerator or error handler that moves the focus.

For example, in a data entry dialog, there might be a field that is only necessary in one per cent of all cases. In such a dialog, Tab could skip this field, and the dialog could use one of these mechanisms:

If the program can determine whether the field is needed, it can move focus there when the user finishes entry and presses OK, or when the user presses Enter after finishing the other fields. Alternately, include the field in the tab order but disable it. Enable it if it becomes appropriate in view of what the user has set in the other fields.

The label for the field can include a keyboard shortcut that moves focus to this field.

Another exception to Tab support is text-entry widgets that must support the insertion of tabs; almost all text editors fall into this class. Qt treats Ctrl+Tab as Tab and Ctrl+Shift+Tab as Shift+Tab, and such widgets can reimplement QWidget::event() and handle Tab before calling QWidget::event() to get normal processing of all other keys. However, since some systems use Ctrl+Tab for other purposes, and many users aren't aware of Ctrl+Tab anyway, this isn't a complete solution.

So you probably will want to use:

QWidget.setTabOrder( nameField, pwdField )
QWidget.setTabOrder( pwdField, btnSubmit )

or something similar.

Hope that helps.

Upvotes: 1

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