ui/base/models/list_selection_model.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_BASE_MODELS_LIST_SELECTION_MODEL_H_
   6 #define UI_BASE_MODELS_LIST_SELECTION_MODEL_H_
   7
   8 #include <vector>
   9
  10 #include "base/basictypes.h"
  11 #include "ui/base/ui_base_export.h"
  12
  13 namespace ui {
  14
  15 // Selection model represented as a list of ints. Used by the TabStrip. In
  16 // addition to the set of selected indices ListSelectionModel maintains the
  17 // following:
  18 // active: the index of the currently visible tab in the tab strip.
  19 // anchor: the index of the last tab the user clicked on. Extending the
  20 // selection extends it from this index.
  21 //
  22 // Typically there is only one selected item, in which case the anchor and
  23 // active index correspond to the same thing.
  24 class UI_BASE_EXPORT ListSelectionModel {
  25  public:
  26   typedef std::vector<int> SelectedIndices;
  27
  28   // Used to identify no selection.
  29   static const int kUnselectedIndex;
  30
  31   ListSelectionModel();
  32   ~ListSelectionModel();
  33
  34   // See class description for details of the anchor.
  35   void set_anchor(int anchor) { anchor_ = anchor; }
  36   int anchor() const { return anchor_; }
  37
  38   // See class description for details of active.
  39   void set_active(int active) { active_ = active; }
  40   int active() const { return active_; }
  41
  42   // True if nothing is selected.
  43   bool empty() const { return selected_indices_.empty(); }
  44
  45   // Number of selected indices.
  46   size_t size() const { return selected_indices_.size(); }
  47
  48   // Increments all indices >= |index|. For example, if the selection consists
  49   // of [0, 1, 5] and this is invoked with 1, it results in [0, 2, 6]. This also
  50   // updates the anchor and active indices.
  51   // This is used when a new tab is inserted into the tabstrip.
  52   void IncrementFrom(int index);
  53
  54   // Shifts all indices > |index| down by 1. If |index| is selected, it is
  55   // removed. For example, if the selection consists of [0, 1, 5] and this is
  56   // invoked with 1, it results in [0, 4]. This is used when a tab is removed
  57   // from the tabstrip.
  58   void DecrementFrom(int index);
  59
  60   // Sets the anchor, active and selection to |index|.
  61   void SetSelectedIndex(int index);
  62
  63   // Returns true if |index| is selected.
  64   bool IsSelected(int index) const;
  65
  66   // Adds |index| to the selection. This does not change the active or anchor
  67   // indices.
  68   void AddIndexToSelection(int index);
  69
  70   // Removes |index| from the selection. This does not change the active or
  71   // anchor indices.
  72   void RemoveIndexFromSelection(int index);
  73
  74   // Extends the selection from the anchor to |index|. If the anchor is empty,
  75   // this sets the anchor, selection and active indices to |index|.
  76   void SetSelectionFromAnchorTo(int index);
  77
  78   // Makes sure the indices from the anchor to |index| are selected. This only
  79   // adds to the selection.
  80   void AddSelectionFromAnchorTo(int index);
  81
  82   // Invoked when an item moves. |from| is the original index, and |to| the
  83   // target index.
  84   // NOTE: this matches the TabStripModel API. If moving to a greater index,
  85   // |to| should be the index *after* removing |from|. For example, consider
  86   // three tabs 'A B C', to move A to the end of the list, this should be
  87   // invoked with '0, 2'.
  88   void Move(int from, int to);
  89
  90   // Sets the anchor and active to kUnselectedIndex, and removes all the
  91   // selected indices.
  92   void Clear();
  93
  94   // Returns the selected indices. The selection is always ordered in acending
  95   // order.
  96   const SelectedIndices& selected_indices() const { return selected_indices_; }
  97
  98   // Copies the selection from |source| to this.
  99   void Copy(const ListSelectionModel& source);
 100
 101   // Compares this selection with |rhs|.
 102   bool Equals(const ListSelectionModel& rhs) const;
 103
 104  private:
 105   SelectedIndices selected_indices_;
 106
 107   int active_;
 108
 109   int anchor_;
 110
 111   DISALLOW_COPY_AND_ASSIGN(ListSelectionModel);
 112 };
 113
 114 }  // namespace ui
 115
 116 #endif  // UI_BASE_MODELS_LIST_SELECTION_MODEL_H_