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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "ui/views/controls/button/button_dropdown.h"
      6 
      7 #include "base/bind.h"
      8 #include "base/compiler_specific.h"
      9 #include "base/message_loop/message_loop.h"
     10 #include "base/strings/utf_string_conversions.h"
     11 #include "grit/ui_strings.h"
     12 #include "ui/base/accessibility/accessible_view_state.h"
     13 #include "ui/base/l10n/l10n_util.h"
     14 #include "ui/base/models/menu_model.h"
     15 #include "ui/gfx/display.h"
     16 #include "ui/gfx/screen.h"
     17 #include "ui/views/controls/menu/menu_item_view.h"
     18 #include "ui/views/controls/menu/menu_model_adapter.h"
     19 #include "ui/views/controls/menu/menu_runner.h"
     20 #include "ui/views/widget/widget.h"
     21 
     22 namespace views {
     23 
     24 // static
     25 const char ButtonDropDown::kViewClassName[] =
     26     "ui/views/controls/button/ButtonDropDown";
     27 
     28 // How long to wait before showing the menu.
     29 const int kMenuTimerDelay = 500;
     30 
     31 ////////////////////////////////////////////////////////////////////////////////
     32 //
     33 // ButtonDropDown - constructors, destructors, initialization, cleanup
     34 //
     35 ////////////////////////////////////////////////////////////////////////////////
     36 
     37 ButtonDropDown::ButtonDropDown(ButtonListener* listener, ui::MenuModel* model)
     38     : ImageButton(listener),
     39       model_(model),
     40       menu_showing_(false),
     41       y_position_on_lbuttondown_(0),
     42       show_menu_factory_(this) {
     43   set_context_menu_controller(this);
     44 }
     45 
     46 ButtonDropDown::~ButtonDropDown() {
     47 }
     48 
     49 void ButtonDropDown::ClearPendingMenu() {
     50   show_menu_factory_.InvalidateWeakPtrs();
     51 }
     52 
     53 bool ButtonDropDown::IsMenuShowing() const {
     54   return menu_showing_;
     55 }
     56 
     57 ////////////////////////////////////////////////////////////////////////////////
     58 //
     59 // ButtonDropDown - Events
     60 //
     61 ////////////////////////////////////////////////////////////////////////////////
     62 
     63 bool ButtonDropDown::OnMousePressed(const ui::MouseEvent& event) {
     64   if (enabled() && ShouldShowMenu() &&
     65       IsTriggerableEvent(event) && HitTestPoint(event.location())) {
     66     // Store the y pos of the mouse coordinates so we can use them later to
     67     // determine if the user dragged the mouse down (which should pop up the
     68     // drag down menu immediately, instead of waiting for the timer)
     69     y_position_on_lbuttondown_ = event.y();
     70 
     71     // Schedule a task that will show the menu.
     72     base::MessageLoop::current()->PostDelayedTask(
     73         FROM_HERE,
     74         base::Bind(&ButtonDropDown::ShowDropDownMenu,
     75                    show_menu_factory_.GetWeakPtr(),
     76                    ui::GetMenuSourceTypeForEvent(event)),
     77         base::TimeDelta::FromMilliseconds(kMenuTimerDelay));
     78   }
     79   return ImageButton::OnMousePressed(event);
     80 }
     81 
     82 bool ButtonDropDown::OnMouseDragged(const ui::MouseEvent& event) {
     83   bool result = ImageButton::OnMouseDragged(event);
     84 
     85   if (show_menu_factory_.HasWeakPtrs()) {
     86     // If the mouse is dragged to a y position lower than where it was when
     87     // clicked then we should not wait for the menu to appear but show
     88     // it immediately.
     89     if (event.y() > y_position_on_lbuttondown_ + GetHorizontalDragThreshold()) {
     90       show_menu_factory_.InvalidateWeakPtrs();
     91       ShowDropDownMenu(ui::GetMenuSourceTypeForEvent(event));
     92     }
     93   }
     94 
     95   return result;
     96 }
     97 
     98 void ButtonDropDown::OnMouseReleased(const ui::MouseEvent& event) {
     99   if (IsTriggerableEvent(event) ||
    100       (event.IsRightMouseButton() && !HitTestPoint(event.location()))) {
    101     ImageButton::OnMouseReleased(event);
    102   }
    103 
    104   if (IsTriggerableEvent(event))
    105     show_menu_factory_.InvalidateWeakPtrs();
    106 }
    107 
    108 const char* ButtonDropDown::GetClassName() const {
    109   return kViewClassName;
    110 }
    111 
    112 void ButtonDropDown::OnMouseExited(const ui::MouseEvent& event) {
    113   // Starting a drag results in a MouseExited, we need to ignore it.
    114   // A right click release triggers an exit event. We want to
    115   // remain in a PUSHED state until the drop down menu closes.
    116   if (state_ != STATE_DISABLED && !InDrag() && state_ != STATE_PRESSED)
    117     SetState(STATE_NORMAL);
    118 }
    119 
    120 void ButtonDropDown::OnGestureEvent(ui::GestureEvent* event) {
    121   if (menu_showing_) {
    122     // While dropdown menu is showing the button should not handle gestures.
    123     event->StopPropagation();
    124     return;
    125   }
    126 
    127   ImageButton::OnGestureEvent(event);
    128 }
    129 
    130 void ButtonDropDown::GetAccessibleState(ui::AccessibleViewState* state) {
    131   CustomButton::GetAccessibleState(state);
    132   state->role = ui::AccessibilityTypes::ROLE_BUTTONDROPDOWN;
    133   state->default_action = l10n_util::GetStringUTF16(IDS_APP_ACCACTION_PRESS);
    134   state->state = ui::AccessibilityTypes::STATE_HASPOPUP;
    135 }
    136 
    137 void ButtonDropDown::ShowContextMenuForView(View* source,
    138                                             const gfx::Point& point,
    139                                             ui::MenuSourceType source_type) {
    140   if (!enabled())
    141     return;
    142 
    143   show_menu_factory_.InvalidateWeakPtrs();
    144   ShowDropDownMenu(source_type);
    145 }
    146 
    147 bool ButtonDropDown::ShouldEnterPushedState(const ui::Event& event) {
    148   // Enter PUSHED state on press with Left or Right mouse button or on taps.
    149   // Remain in this state while the context menu is open.
    150   return event.type() == ui::ET_GESTURE_TAP ||
    151          event.type() == ui::ET_GESTURE_TAP_DOWN ||
    152          (event.IsMouseEvent() && ((ui::EF_LEFT_MOUSE_BUTTON |
    153              ui::EF_RIGHT_MOUSE_BUTTON) & event.flags()) != 0);
    154 }
    155 
    156 bool ButtonDropDown::ShouldShowMenu() {
    157   return true;
    158 }
    159 
    160 void ButtonDropDown::ShowDropDownMenu(ui::MenuSourceType source_type) {
    161   if (!ShouldShowMenu())
    162     return;
    163 
    164   gfx::Rect lb = GetLocalBounds();
    165 
    166   // Both the menu position and the menu anchor type change if the UI layout
    167   // is right-to-left.
    168   gfx::Point menu_position(lb.origin());
    169   menu_position.Offset(0, lb.height() - 1);
    170   if (base::i18n::IsRTL())
    171     menu_position.Offset(lb.width() - 1, 0);
    172 
    173   View::ConvertPointToScreen(this, &menu_position);
    174 
    175 #if defined(OS_WIN)
    176   int left_bound = GetSystemMetrics(SM_XVIRTUALSCREEN);
    177 #elif defined(OS_CHROMEOS)
    178   // A window won't overlap between displays on ChromeOS.
    179   // Use the left bound of the display on which
    180   // the menu button exists.
    181   gfx::NativeView view = GetWidget()->GetNativeView();
    182   gfx::Display display = gfx::Screen::GetScreenFor(
    183       view)->GetDisplayNearestWindow(view);
    184   int left_bound = display.bounds().x();
    185 #else
    186   int left_bound = 0;
    187   NOTIMPLEMENTED();
    188 #endif
    189   if (menu_position.x() < left_bound)
    190     menu_position.set_x(left_bound);
    191 
    192   // Make the button look depressed while the menu is open.
    193   SetState(STATE_PRESSED);
    194 
    195   menu_showing_ = true;
    196 
    197   // Create and run menu.  Display an empty menu if model is NULL.
    198   if (model_.get()) {
    199     MenuModelAdapter menu_delegate(model_.get());
    200     menu_delegate.set_triggerable_event_flags(triggerable_event_flags());
    201     menu_runner_.reset(new MenuRunner(menu_delegate.CreateMenu()));
    202     MenuRunner::RunResult result =
    203         menu_runner_->RunMenuAt(GetWidget(), NULL,
    204                                 gfx::Rect(menu_position, gfx::Size(0, 0)),
    205                                 MenuItemView::TOPLEFT,
    206                                 source_type,
    207                                 MenuRunner::HAS_MNEMONICS);
    208     if (result == MenuRunner::MENU_DELETED)
    209       return;
    210   } else {
    211     MenuDelegate menu_delegate;
    212     MenuItemView* menu = new MenuItemView(&menu_delegate);
    213     menu_runner_.reset(new MenuRunner(menu));
    214     MenuRunner::RunResult result =
    215         menu_runner_->RunMenuAt(GetWidget(), NULL,
    216                                 gfx::Rect(menu_position, gfx::Size(0, 0)),
    217                                 MenuItemView::TOPLEFT,
    218                                 source_type,
    219                                 MenuRunner::HAS_MNEMONICS);
    220     if (result == MenuRunner::MENU_DELETED)
    221       return;
    222   }
    223 
    224   menu_showing_ = false;
    225 
    226   // Need to explicitly clear mouse handler so that events get sent
    227   // properly after the menu finishes running. If we don't do this, then
    228   // the first click to other parts of the UI is eaten.
    229   SetMouseHandler(NULL);
    230 
    231   // Set the state back to normal after the drop down menu is closed.
    232   if (state_ != STATE_DISABLED)
    233     SetState(STATE_NORMAL);
    234 }
    235 
    236 ////////////////////////////////////////////////////////////////////////////////
    237 //
    238 // ButtonDropDown - Accessibility
    239 //
    240 ////////////////////////////////////////////////////////////////////////////////
    241 
    242 }  // namespace views
    243