tdesktop/Telegram/SourceFiles/ui/focus_persister.h

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2017-09-25 16:06:53 +00:00
/*
This file is part of Telegram Desktop,
the official desktop version of Telegram messaging app, see https://telegram.org
Telegram Desktop is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
It is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
In addition, as a special exception, the copyright holders give permission
to link the code of portions of this program with the OpenSSL library.
Full license: https://github.com/telegramdesktop/tdesktop/blob/master/LICENSE
Copyright (c) 2014-2017 John Preston, https://desktop.telegram.org
*/
#pragma once
namespace Ui {
class FocusPersister {
public:
FocusPersister(QWidget *parent, QWidget *steal = nullptr)
: _weak(GrabFocused(parent)) {
if (steal) {
steal->setFocus();
}
}
~FocusPersister() {
if (auto strong = _weak.data()) {
if (auto window = strong->window()) {
if (window->focusWidget() != strong) {
strong->setFocus();
}
}
}
}
private:
static QWidget *GrabFocused(QWidget *parent) {
if (auto window = parent ? parent->window() : nullptr) {
return window->focusWidget();
}
return nullptr;
}
QPointer<QWidget> _weak;
};
} // namespace Ui