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#ifndef UI_VIEWS_CONTROLS_MENU_MENU_DELEGATE_H_
6#define UI_VIEWS_CONTROLS_MENU_MENU_DELEGATE_H_
7
8#include <set>
9#include <string>
10
11#include "base/logging.h"
12#include "base/strings/string16.h"
13#include "third_party/skia/include/core/SkColor.h"
14#include "ui/base/dragdrop/drag_drop_types.h"
15#include "ui/base/dragdrop/os_exchange_data.h"
16#include "ui/base/ui_base_types.h"
17#include "ui/views/controls/menu/menu_types.h"
18#include "ui/views/views_export.h"
19
20using ui::OSExchangeData;
21
22namespace gfx {
23class FontList;
24class Point;
25}
26
27namespace ui {
28class Accelerator;
29class DropTargetEvent;
30}
31
32namespace views {
33
34class MenuButton;
35class MenuItemView;
36
37// MenuDelegate --------------------------------------------------------------
38
39// Delegate for a menu. This class is used as part of MenuItemView, see it
40// for details.
41// TODO(sky): merge this with ui::MenuModel.
42class VIEWS_EXPORT MenuDelegate {
43 public:
44  // Used during drag and drop to indicate where the drop indicator should
45  // be rendered.
46  enum DropPosition {
47    DROP_UNKNOWN = -1,
48
49    // Indicates a drop is not allowed here.
50    DROP_NONE,
51
52    // Indicates the drop should occur before the item.
53    DROP_BEFORE,
54
55    // Indicates the drop should occur after the item.
56    DROP_AFTER,
57
58    // Indicates the drop should occur on the item.
59    DROP_ON
60  };
61
62  virtual ~MenuDelegate();
63
64  // Whether or not an item should be shown as checked. This is invoked for
65  // radio buttons and check buttons.
66  virtual bool IsItemChecked(int id) const;
67
68  // The string shown for the menu item. This is only invoked when an item is
69  // added with an empty label.
70  virtual base::string16 GetLabel(int id) const;
71
72  // The font for the menu item label.
73  virtual const gfx::FontList* GetLabelFontList(int id) const;
74
75  // Whether this item should be displayed with a bolder color when disabled.
76  virtual bool GetShouldUseDisabledEmphasizedForegroundColor(
77      int command_id) const;
78
79  // Override the text color of a given menu item dependent on the
80  // |command_id| and its |is_hovered| state. Returns true if it chooses to
81  // override the color.
82  //
83  // TODO(erg): Remove this interface. Injecting raw colors into the menu
84  // circumvents the NativeTheme.
85  virtual bool GetForegroundColor(int command_id,
86                                  bool is_hovered,
87                                  SkColor* override_color) const;
88
89  // Override the background color of a given menu item dependent on the
90  // |command_id| and its |is_hovered| state. Returns true if it chooses to
91  // override the color.
92  //
93  // TODO(erg): Remove this interface. Injecting raw colors into the menu
94  // circumvents the NativeTheme.
95  virtual bool GetBackgroundColor(int command_id,
96                                  bool is_hovered,
97                                  SkColor* override_color) const;
98
99  // The tooltip shown for the menu item. This is invoked when the user
100  // hovers over the item, and no tooltip text has been set for that item.
101  virtual base::string16 GetTooltipText(int id,
102                                        const gfx::Point& screen_loc) const;
103
104  // If there is an accelerator for the menu item with id |id| it is set in
105  // |accelerator| and true is returned.
106  virtual bool GetAccelerator(int id, ui::Accelerator* accelerator) const;
107
108  // Shows the context menu with the specified id. This is invoked when the
109  // user does the appropriate gesture to show a context menu. The id
110  // identifies the id of the menu to show the context menu for.
111  // is_mouse_gesture is true if this is the result of a mouse gesture.
112  // If this is not the result of a mouse gesture |p| is the recommended
113  // location to display the content menu at. In either case, |p| is in
114  // screen coordinates.
115  // Returns true if a context menu was displayed, otherwise false
116  virtual bool ShowContextMenu(MenuItemView* source,
117                               int id,
118                               const gfx::Point& p,
119                               ui::MenuSourceType source_type);
120
121  // Controller
122  virtual bool SupportsCommand(int id) const;
123  virtual bool IsCommandEnabled(int id) const;
124  virtual bool IsCommandVisible(int id) const;
125  virtual bool GetContextualLabel(int id, base::string16* out) const;
126  virtual void ExecuteCommand(int id) {
127  }
128
129  // If nested menus are showing (nested menus occur when a menu shows a context
130  // menu) this is invoked to determine if all the menus should be closed when
131  // the user selects the menu with the command |id|. This returns true to
132  // indicate that all menus should be closed. Return false if only the
133  // context menu should be closed.
134  virtual bool ShouldCloseAllMenusOnExecute(int id);
135
136  // Executes the specified command. mouse_event_flags give the flags of the
137  // mouse event that triggered this to be invoked (ui::MouseEvent
138  // flags). mouse_event_flags is 0 if this is triggered by a user gesture
139  // other than a mouse event.
140  virtual void ExecuteCommand(int id, int mouse_event_flags);
141
142  // Returns true if ExecuteCommand() should be invoked while leaving the
143  // menu open. Default implementation returns true.
144  virtual bool ShouldExecuteCommandWithoutClosingMenu(int id,
145                                                      const ui::Event& e);
146
147  // Returns true if the specified event is one the user can use to trigger, or
148  // accept, the item. Defaults to left or right mouse buttons or tap.
149  virtual bool IsTriggerableEvent(MenuItemView* view, const ui::Event& e);
150
151  // Invoked to determine if drops can be accepted for a submenu. This is
152  // ONLY invoked for menus that have submenus and indicates whether or not
153  // a drop can occur on any of the child items of the item. For example,
154  // consider the following menu structure:
155  //
156  // A
157  //   B
158  //   C
159  //
160  // Where A has a submenu with children B and C. This is ONLY invoked for
161  // A, not B and C.
162  //
163
164  // To restrict which children can be dropped on override GetDropOperation.
165  virtual bool CanDrop(MenuItemView* menu, const OSExchangeData& data);
166
167  // See view for a description of this method.
168  virtual bool GetDropFormats(
169      MenuItemView* menu,
170      int* formats,
171      std::set<OSExchangeData::CustomFormat>* custom_formats);
172
173  // See view for a description of this method.
174  virtual bool AreDropTypesRequired(MenuItemView* menu);
175
176  // Returns the drop operation for the specified target menu item. This is
177  // only invoked if CanDrop returned true for the parent menu. position
178  // is set based on the location of the mouse, reset to specify a different
179  // position.
180  //
181  // If a drop should not be allowed, returned ui::DragDropTypes::DRAG_NONE.
182  virtual int GetDropOperation(MenuItemView* item,
183                               const ui::DropTargetEvent& event,
184                               DropPosition* position);
185
186  // Invoked to perform the drop operation. This is ONLY invoked if CanDrop()
187  // returned true for the parent menu item, and GetDropOperation() returned an
188  // operation other than ui::DragDropTypes::DRAG_NONE.
189  //
190  // |menu| is the menu the drop occurred on.
191  virtual int OnPerformDrop(MenuItemView* menu,
192                            DropPosition position,
193                            const ui::DropTargetEvent& event);
194
195  // Invoked to determine if it is possible for the user to drag the specified
196  // menu item.
197  virtual bool CanDrag(MenuItemView* menu);
198
199  // Invoked to write the data for a drag operation to data. sender is the
200  // MenuItemView being dragged.
201  virtual void WriteDragData(MenuItemView* sender, OSExchangeData* data);
202
203  // Invoked to determine the drag operations for a drag session of sender.
204  // See DragDropTypes for possible values.
205  virtual int GetDragOperations(MenuItemView* sender);
206
207  // Notification the menu has closed. This is only sent when running the
208  // menu for a drop.
209  virtual void DropMenuClosed(MenuItemView* menu) {
210  }
211
212  // Returns true if the menu should close upon a drag completing. Defaults to
213  // true. This is only invoked for drag and drop operations performed on child
214  // Views that are not MenuItemViews.
215  virtual bool ShouldCloseOnDragComplete();
216
217  // Notification that the user has highlighted the specified item.
218  virtual void SelectionChanged(MenuItemView* menu) {
219  }
220
221  // If the user drags the mouse outside the bounds of the menu the delegate
222  // is queried for a sibling menu to show. If this returns non-null the
223  // current menu is hidden, and the menu returned from this method is shown.
224  //
225  // The delegate owns the returned menu, not the controller.
226  virtual MenuItemView* GetSiblingMenu(MenuItemView* menu,
227                                       const gfx::Point& screen_point,
228                                       MenuAnchorPosition* anchor,
229                                       bool* has_mnemonics,
230                                       MenuButton** button);
231
232  // Returns the max width menus can grow to be.
233  virtual int GetMaxWidthForMenu(MenuItemView* menu);
234
235  // Invoked prior to a menu being shown.
236  virtual void WillShowMenu(MenuItemView* menu);
237
238  // Invoked prior to a menu being hidden.
239  virtual void WillHideMenu(MenuItemView* menu);
240
241  // Returns additional horizontal spacing for the icon of the given item.
242  // The |command_id| specifies the item of interest, the |icon_size| tells the
243  // function the size of the icon and it will then return |left_margin|
244  // and |right_margin| accordingly. Note: Negative values can be returned.
245  virtual void GetHorizontalIconMargins(int command_id,
246                                        int icon_size,
247                                        int* left_margin,
248                                        int* right_margin) const;
249  // Returns true if the labels should reserve additional spacing for e.g.
250  // submenu indicators at the end of the line.
251  virtual bool ShouldReserveSpaceForSubmenuIndicator() const;
252};
253
254}  // namespace views
255
256#endif  // UI_VIEWS_CONTROLS_MENU_MENU_DELEGATE_H_
257