cef/libcef/browser/views/widget_destruction_observer.h

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views: Add support for modal browser dialogs A modal dialog is a child CefWindow that implements some special behaviors relative to a parent CefWindow. Like any CefWindow it can be framed with titlebar or frameless, and optionally contain draggable regions (subject to platform limitations described below). Modal dialogs are shown centered on the parent window (inside a single display) and always stay on top of the parent window in z-order. Sizing behavior and available window buttons are controlled via the usual CefWindowDelegate callbacks. For example, the dialog can have a preferred size with resize, minimize and maximize disabled (via GetPreferredSize, CanResize, CanMinimize and CanMaximize respectively). This change adds support for two modality modes. With window modality all controls in the parent window are disabled. With browser modality only the browser view in the parent window is disabled. Both modality modes require that a valid parent window be returned via GetParentWindow. For window modality return true from IsWindowModalDialog and call CefWindow::Show. For browser modality return false from IsWindowModalDialog (the default value) and call CefWindow::ShowAsBrowserModalDialog with a reference to the parent window's browser view. Window modal dialog behavior depends on the platform. On Windows and Linux these dialogs have a titlebar and can be moved independent of the parent window. On macOS these dialogs do not have a titlebar, move with the parent window, and do not support draggable regions (because they are implemented using sheets). On Linux disabling the parent window controls requires a window manager the supports _NET_WM_STATE_MODAL. Browser modal dialog behavior is similar on all platforms. The dialog will be automatically sized and positioned relative to the parent window's browser view. Closing the parent window or navigating the parent browser view will dismiss the dialog. The dialog can also be moved independent of the parent window though it will be recentered when the parent window itself is resized or redisplayed. On MacOS the dialog will move along with the parent window while on Windows and Linux the parent window can be moved independently. To test: Use the Tests > Dialog Window menu option in cefclient with Views enabled (`--use-views` or `--enable-chrome-runtime` command-line flag). Browser modal dialog is the default behavior. For window modal dialog add the `--use-window-modal-dialog` command-line flag.
2023-06-14 10:20:02 +02:00
// Copyright 2023 The Chromium Embedded Framework Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be found
// in the LICENSE file.
#include "base/scoped_observation.h"
#include "ui/views/widget/widget_observer.h"
// Tracks if a given widget has been destroyed.
class WidgetDestructionObserver : public views::WidgetObserver {
public:
explicit WidgetDestructionObserver(views::Widget* widget) : widget_(widget) {
DCHECK(widget);
observation_.Observe(widget);
}
WidgetDestructionObserver(const WidgetDestructionObserver&) = delete;
WidgetDestructionObserver& operator=(const WidgetDestructionObserver&) =
delete;
~WidgetDestructionObserver() override = default;
// views::WidgetObserver:
void OnWidgetDestroyed(views::Widget* widget) override {
DCHECK(widget_);
widget_ = nullptr;
observation_.Reset();
}
views::Widget* widget() const { return widget_; }
private:
views::Widget* widget_;
base::ScopedObservation<views::Widget, views::WidgetObserver> observation_{
this};
};