Correct way to set focus on widget

SPlatten

I have an instance of QLineEdit, when I enter content I have a QPushButton that I can click to undo the edit and roll back, I have a slot connected to the signal emitted when the button is clicked, after roll back occurs I want the focus to return the the QLineEdit. This is the slot that is called when the undo signal is emitted:

void clsQtLineEdit::onUndoChange() {
    clsXMLinterface* pobjXMLIF(dynamic_cast<clsXMLinterface*>(this));
    if ( pobjXMLIF == nullptr ) {
        return;
    }
    if ( mintUndoRedoIdx == -1 || mintUndoRedoIdx >= mpobjUndoRedo->size() ) {
    //Default to the end of the stack
        mintUndoRedoIdx = mpobjUndoRedo->size() - 1;
    }
    if ( mintUndoRedoIdx > 0 ) {
        const QJsonValue cobjJSON(pobjXMLIF->at(--mintUndoRedoIdx));
        setData(cobjJSON.toString(), false);
    }
    pobjXMLIF->setUndoRedoButtonStates();    
    setFocus();
}

What seems to happen is the undo works but the next QLineEdit gets the focus not the original.

For example, my form contains two instances of QLineEdit, lets call them A and B, if A has the focus and has the content 1234, I click the button which performs the undo, but instead of A getting the focus, the focus moves to B. I then have to click A again to give it the focus.

SGaist

Hi,

How do you connect your multiple line edits to that undo button ?

SPlatten

@SGaist , in the constructor for clsQtLineEdit:

        cn = QObject::connect(mpobjWindow, &clsXMLnode::undoChanges
                             ,this, &clsQtLineEdit::onUndoChange);
        Q_ASSERT_X(cn, clsQtLineEdit::metaObject()->className()
                  ,QString("Cannot connect %1!").arg(clsXMLnode::mscszSignalUndoChanges)
                              .toLocal8Bit().data());

I see where you are going, thank you for the suggestion, as all the instances get the same signal I need to add something to the class to track if it had the focus before the undo was pressed.

[Edit] to my event filter I added:

    if ( evtType == QEvent::FocusIn ) {
        setControlFocus();
...

The setControlFocus:

void clsXMLnode::setControlFocus() {
    if ( blnIsInteractive() == true && blnExcludedFromCC() != true ) {
        clsXMLnode* pobjWindow(pobjGetWindow());
        if ( pobjWindow == nullptr ) {
            return;
        }
        QWidget* pobjWidget(pobjGetWidget());
        clsXMLinterface* pobjXMLIF(dynamic_cast<clsXMLinterface*>(pobjWidget));
        if  ( pobjXMLIF != nullptr ) {
            pobjXMLIF->setUndoRedoButtonStates();
        }
        pobjWindow->mpobjFocused = pobjWidget;
    }
}

In the onUndoChange slot, on entry:

    if ( mpobjNode->blnCheckAndRestoreFocus(*this) != true ) {
        return;
    }

This now works perfectly, thank you.

SGaist

Just in case, Qt has the undo framework.

SPlatten

@SGaist , yes, seen it