ui/views/controls/menu/menu_delegate.h

   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
  20 using ui::OSExchangeData;
  21
  22 namespace gfx {
  23 class FontList;
  24 class Point;
  25 }
  26
  27 namespace ui {
  28 class Accelerator;
  29 class DropTargetEvent;
  30 }
  31
  32 namespace views {
  33
  34 class MenuButton;
  35 class 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.
  42 class 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 GetContextualLabel(int id, base::string16* out) const;
 125   virtual void ExecuteCommand(int id) {
 126   }
 127
 128   // If nested menus are showing (nested menus occur when a menu shows a context
 129   // menu) this is invoked to determine if all the menus should be closed when
 130   // the user selects the menu with the command |id|. This returns true to
 131   // indicate that all menus should be closed. Return false if only the
 132   // context menu should be closed.
 133   virtual bool ShouldCloseAllMenusOnExecute(int id);
 134
 135   // Executes the specified command. mouse_event_flags give the flags of the
 136   // mouse event that triggered this to be invoked (ui::MouseEvent
 137   // flags). mouse_event_flags is 0 if this is triggered by a user gesture
 138   // other than a mouse event.
 139   virtual void ExecuteCommand(int id, int mouse_event_flags);
 140
 141   // Returns true if ExecuteCommand() should be invoked while leaving the
 142   // menu open. Default implementation returns true.
 143   virtual bool ShouldExecuteCommandWithoutClosingMenu(int id,
 144                                                       const ui::Event& e);
 145
 146   // Returns true if the specified event is one the user can use to trigger, or
 147   // accept, the item. Defaults to left or right mouse buttons or tap.
 148   virtual bool IsTriggerableEvent(MenuItemView* view, const ui::Event& e);
 149
 150   // Invoked to determine if drops can be accepted for a submenu. This is
 151   // ONLY invoked for menus that have submenus and indicates whether or not
 152   // a drop can occur on any of the child items of the item. For example,
 153   // consider the following menu structure:
 154   //
 155   // A
 156   //   B
 157   //   C
 158   //
 159   // Where A has a submenu with children B and C. This is ONLY invoked for
 160   // A, not B and C.
 161   //
 162
 163   // To restrict which children can be dropped on override GetDropOperation.
 164   virtual bool CanDrop(MenuItemView* menu, const OSExchangeData& data);
 165
 166   // See view for a description of this method.
 167   virtual bool GetDropFormats(
 168       MenuItemView* menu,
 169       int* formats,
 170       std::set<OSExchangeData::CustomFormat>* custom_formats);
 171
 172   // See view for a description of this method.
 173   virtual bool AreDropTypesRequired(MenuItemView* menu);
 174
 175   // Returns the drop operation for the specified target menu item. This is
 176   // only invoked if CanDrop returned true for the parent menu. position
 177   // is set based on the location of the mouse, reset to specify a different
 178   // position.
 179   //
 180   // If a drop should not be allowed, returned ui::DragDropTypes::DRAG_NONE.
 181   virtual int GetDropOperation(MenuItemView* item,
 182                                const ui::DropTargetEvent& event,
 183                                DropPosition* position);
 184
 185   // Invoked to perform the drop operation. This is ONLY invoked if CanDrop()
 186   // returned true for the parent menu item, and GetDropOperation() returned an
 187   // operation other than ui::DragDropTypes::DRAG_NONE.
 188   //
 189   // |menu| is the menu the drop occurred on.
 190   virtual int OnPerformDrop(MenuItemView* menu,
 191                             DropPosition position,
 192                             const ui::DropTargetEvent& event);
 193
 194   // Invoked to determine if it is possible for the user to drag the specified
 195   // menu item.
 196   virtual bool CanDrag(MenuItemView* menu);
 197
 198   // Invoked to write the data for a drag operation to data. sender is the
 199   // MenuItemView being dragged.
 200   virtual void WriteDragData(MenuItemView* sender, OSExchangeData* data);
 201
 202   // Invoked to determine the drag operations for a drag session of sender.
 203   // See DragDropTypes for possible values.
 204   virtual int GetDragOperations(MenuItemView* sender);
 205
 206   // Notification the menu has closed. This is only sent when running the
 207   // menu for a drop.
 208   virtual void DropMenuClosed(MenuItemView* menu) {
 209   }
 210
 211   // Returns true if the menu should close upon a drag completing. Defaults to
 212   // true. This is only invoked for drag and drop operations performed on child
 213   // Views that are not MenuItemViews.
 214   virtual bool ShouldCloseOnDragComplete();
 215
 216   // Notification that the user has highlighted the specified item.
 217   virtual void SelectionChanged(MenuItemView* menu) {
 218   }
 219
 220   // If the user drags the mouse outside the bounds of the menu the delegate
 221   // is queried for a sibling menu to show. If this returns non-null the
 222   // current menu is hidden, and the menu returned from this method is shown.
 223   //
 224   // The delegate owns the returned menu, not the controller.
 225   virtual MenuItemView* GetSiblingMenu(MenuItemView* menu,
 226                                        const gfx::Point& screen_point,
 227                                        MenuAnchorPosition* anchor,
 228                                        bool* has_mnemonics,
 229                                        MenuButton** button);
 230
 231   // Returns the max width menus can grow to be.
 232   virtual int GetMaxWidthForMenu(MenuItemView* menu);
 233
 234   // Invoked prior to a menu being shown.
 235   virtual void WillShowMenu(MenuItemView* menu);
 236
 237   // Invoked prior to a menu being hidden.
 238   virtual void WillHideMenu(MenuItemView* menu);
 239
 240   // Returns additional horizontal spacing for the icon of the given item.
 241   // The |command_id| specifies the item of interest, the |icon_size| tells the
 242   // function the size of the icon and it will then return |left_margin|
 243   // and |right_margin| accordingly. Note: Negative values can be returned.
 244   virtual void GetHorizontalIconMargins(int command_id,
 245                                         int icon_size,
 246                                         int* left_margin,
 247                                         int* right_margin) const;
 248   // Returns true if the labels should reserve additional spacing for e.g.
 249   // submenu indicators at the end of the line.
 250   virtual bool ShouldReserveSpaceForSubmenuIndicator() const;
 251 };
 252
 253 }  // namespace views
 254
 255 #endif  // UI_VIEWS_CONTROLS_MENU_MENU_DELEGATE_H_