views/controls/button/button_dropdown.cc

// Copyright (c) 2011 The Chromium 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 "views/controls/button/button_dropdown.h"

#include "base/bind.h"
#include "base/compiler_specific.h"
#include "base/message_loop.h"
#include "base/utf_string_conversions.h"
#include "grit/ui_strings.h"
#include "ui/base/accessibility/accessible_view_state.h"
#include "ui/base/l10n/l10n_util.h"
#include "ui/base/models/menu_model.h"
#include "views/controls/menu/menu_item_view.h"
#include "views/controls/menu/menu_model_adapter.h"
#include "views/controls/menu/menu_runner.h"
#include "views/widget/widget.h"

namespace views {

// static
const char ButtonDropDown::kViewClassName[] =
    "views/controls/button/ButtonDropDown";

// How long to wait before showing the menu.
const int kMenuTimerDelay = 500;

////////////////////////////////////////////////////////////////////////////////
//
// ButtonDropDown - constructors, destructors, initialization, cleanup
//
////////////////////////////////////////////////////////////////////////////////

ButtonDropDown::ButtonDropDown(ButtonListener* listener, ui::MenuModel* model)
    : ImageButton(listener),
      model_(model),
      y_position_on_lbuttondown_(0),
      ALLOW_THIS_IN_INITIALIZER_LIST(show_menu_factory_(this)) {
}

ButtonDropDown::~ButtonDropDown() {
}

////////////////////////////////////////////////////////////////////////////////
//
// ButtonDropDown - Events
//
////////////////////////////////////////////////////////////////////////////////

bool ButtonDropDown::OnMousePressed(const MouseEvent& event) {
  if (IsEnabled() && IsTriggerableEvent(event) && HitTest(event.location())) {
    // Store the y pos of the mouse coordinates so we can use them later to
    // determine if the user dragged the mouse down (which should pop up the
    // drag down menu immediately, instead of waiting for the timer)
    y_position_on_lbuttondown_ = event.y();

    // Schedule a task that will show the menu.
    MessageLoop::current()->PostDelayedTask(
        FROM_HERE,
        base::Bind(&ButtonDropDown::ShowDropDownMenu,
                   show_menu_factory_.GetWeakPtr(),
                   GetWidget()->GetNativeView()),
        kMenuTimerDelay);
  }
  return ImageButton::OnMousePressed(event);
}

bool ButtonDropDown::OnMouseDragged(const MouseEvent& event) {
  bool result = ImageButton::OnMouseDragged(event);

  if (show_menu_factory_.HasWeakPtrs()) {
    // If the mouse is dragged to a y position lower than where it was when
    // clicked then we should not wait for the menu to appear but show
    // it immediately.
    if (event.y() > y_position_on_lbuttondown_ + GetHorizontalDragThreshold()) {
      show_menu_factory_.InvalidateWeakPtrs();
      ShowDropDownMenu(GetWidget()->GetNativeView());
    }
  }

  return result;
}

void ButtonDropDown::OnMouseReleased(const MouseEvent& event) {
  if (IsTriggerableEvent(event) ||
      (event.IsRightMouseButton() && !HitTest(event.location()))) {
    ImageButton::OnMouseReleased(event);
  }

  if (IsTriggerableEvent(event))
    show_menu_factory_.InvalidateWeakPtrs();

  if (IsEnabled() && event.IsRightMouseButton() && HitTest(event.location())) {
    show_menu_factory_.InvalidateWeakPtrs();
    ShowDropDownMenu(GetWidget()->GetNativeView());
  }
}

std::string ButtonDropDown::GetClassName() const {
  return kViewClassName;
}

void ButtonDropDown::OnMouseExited(const MouseEvent& event) {
  // Starting a drag results in a MouseExited, we need to ignore it.
  // A right click release triggers an exit event. We want to
  // remain in a PUSHED state until the drop down menu closes.
  if (state_ != BS_DISABLED && !InDrag() && state_ != BS_PUSHED)
    SetState(BS_NORMAL);
}

void ButtonDropDown::ShowContextMenu(const gfx::Point& p,
                                     bool is_mouse_gesture) {
  show_menu_factory_.InvalidateWeakPtrs();
  ShowDropDownMenu(GetWidget()->GetNativeView());
  SetState(BS_HOT);
}

void ButtonDropDown::GetAccessibleState(ui::AccessibleViewState* state) {
  CustomButton::GetAccessibleState(state);
  state->role = ui::AccessibilityTypes::ROLE_BUTTONDROPDOWN;
  state->default_action = l10n_util::GetStringUTF16(IDS_APP_ACCACTION_PRESS);
  state->state = ui::AccessibilityTypes::STATE_HASPOPUP;
}

bool ButtonDropDown::ShouldEnterPushedState(const MouseEvent& event) {
  // Enter PUSHED state on press with Left or Right mouse button. Remain
  // in this state while the context menu is open.
  return ((ui::EF_LEFT_BUTTON_DOWN |
      ui::EF_RIGHT_BUTTON_DOWN) & event.flags()) != 0;
}

void ButtonDropDown::ShowDropDownMenu(gfx::NativeView window) {
  gfx::Rect lb = GetLocalBounds();

  // Both the menu position and the menu anchor type change if the UI layout
  // is right-to-left.
  gfx::Point menu_position(lb.origin());
  menu_position.Offset(0, lb.height() - 1);
  if (base::i18n::IsRTL())
    menu_position.Offset(lb.width() - 1, 0);

  View::ConvertPointToScreen(this, &menu_position);

#if defined(OS_WIN)
  int left_bound = GetSystemMetrics(SM_XVIRTUALSCREEN);
#else
  int left_bound = 0;
  NOTIMPLEMENTED();
#endif
  if (menu_position.x() < left_bound)
    menu_position.set_x(left_bound);

  // Make the button look depressed while the menu is open.
  SetState(BS_PUSHED);

  // Create and run menu.  Display an empty menu if model is NULL.
  if (model_) {
    MenuModelAdapter menu_delegate(model_);
    menu_delegate.set_triggerable_event_flags(triggerable_event_flags());
    MenuRunner runner(menu_delegate.CreateMenu());
    if (runner.RunMenuAt(GetWidget(), NULL,
                         gfx::Rect(menu_position, gfx::Size(0, 0)),
                         MenuItemView::TOPLEFT,
                         MenuRunner::HAS_MNEMONICS) == MenuRunner::MENU_DELETED)
      return;
  } else {
    MenuDelegate menu_delegate;
    MenuItemView* menu = new MenuItemView(&menu_delegate);
    MenuRunner runner(menu);
    if (runner.RunMenuAt(GetWidget(), NULL,
                         gfx::Rect(menu_position, gfx::Size(0, 0)),
                         views::MenuItemView::TOPLEFT,
                         MenuRunner::HAS_MNEMONICS) == MenuRunner::MENU_DELETED)
      return;
  }

  // Need to explicitly clear mouse handler so that events get sent
  // properly after the menu finishes running. If we don't do this, then
  // the first click to other parts of the UI is eaten.
  SetMouseHandler(NULL);

  // Set the state back to normal after the drop down menu is closed.
  if (state_ != BS_DISABLED)
    SetState(BS_NORMAL);
}

////////////////////////////////////////////////////////////////////////////////
//
// ButtonDropDown - Accessibility
//
////////////////////////////////////////////////////////////////////////////////

}  // namespace views