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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 #ifndef UI_VIEWS_CONTROLS_TREE_TREE_VIEW_VIEWS_H_
      6 #define UI_VIEWS_CONTROLS_TREE_TREE_VIEW_VIEWS_H_
      7 
      8 #include <vector>
      9 
     10 #include "base/basictypes.h"
     11 #include "base/compiler_specific.h"
     12 #include "base/memory/scoped_ptr.h"
     13 #include "ui/base/models/tree_node_model.h"
     14 #include "ui/gfx/font.h"
     15 #include "ui/gfx/image/image_skia.h"
     16 #include "ui/views/controls/prefix_delegate.h"
     17 #include "ui/views/controls/textfield/textfield_controller.h"
     18 #include "ui/views/focus/focus_manager.h"
     19 #include "ui/views/view.h"
     20 
     21 namespace views {
     22 
     23 class Textfield;
     24 class TreeViewController;
     25 class PrefixSelector;
     26 
     27 // TreeView displays hierarchical data as returned from a TreeModel. The user
     28 // can expand, collapse and edit the items. A Controller may be attached to
     29 // receive notification of selection changes and restrict editing.
     30 //
     31 // Note on implementation. This implementation doesn't scale well. In particular
     32 // it does not store any row information, but instead calculates it as
     33 // necessary. But it's more than adequate for current uses.
     34 class VIEWS_EXPORT TreeView : public ui::TreeModelObserver,
     35                               public TextfieldController,
     36                               public FocusChangeListener,
     37                               public PrefixDelegate {
     38  public:
     39   TreeView();
     40   virtual ~TreeView();
     41 
     42   // Returns new ScrollPane that contains the receiver.
     43   View* CreateParentIfNecessary();
     44 
     45   // Sets the model. TreeView does not take ownership of the model.
     46   void SetModel(ui::TreeModel* model);
     47   ui::TreeModel* model() const { return model_; }
     48 
     49   // Sets whether to automatically expand children when a parent node is
     50   // expanded. The default is false. If true, when a node in the tree is
     51   // expanded for the first time, its children are also automatically expanded.
     52   // If a node is subsequently collapsed and expanded again, the children
     53   // will not be automatically expanded.
     54   void set_auto_expand_children(bool auto_expand_children) {
     55     auto_expand_children_ = auto_expand_children;
     56   }
     57 
     58   // Sets whether the user can edit the nodes. The default is true. If true,
     59   // the Controller is queried to determine if a particular node can be edited.
     60   void SetEditable(bool editable);
     61 
     62   // Edits the specified node. This cancels the current edit and expands all
     63   // parents of node.
     64   void StartEditing(ui::TreeModelNode* node);
     65 
     66   // Cancels the current edit. Does nothing if not editing.
     67   void CancelEdit();
     68 
     69   // Commits the current edit. Does nothing if not editing.
     70   void CommitEdit();
     71 
     72   // If the user is editing a node, it is returned. If the user is not
     73   // editing a node, NULL is returned.
     74   ui::TreeModelNode* GetEditingNode();
     75 
     76   // Selects the specified node. This expands all the parents of node.
     77   void SetSelectedNode(ui::TreeModelNode* model_node);
     78 
     79   // Returns the selected node, or NULL if nothing is selected.
     80   ui::TreeModelNode* GetSelectedNode();
     81 
     82   // Marks |model_node| as collapsed. This only effects the UI if node and all
     83   // its parents are expanded (IsExpanded(model_node) returns true).
     84   void Collapse(ui::TreeModelNode* model_node);
     85 
     86   // Make sure node and all its parents are expanded.
     87   void Expand(ui::TreeModelNode* node);
     88 
     89   // Invoked from ExpandAll(). Expands the supplied node and recursively
     90   // invokes itself with all children.
     91   void ExpandAll(ui::TreeModelNode* node);
     92 
     93   // Returns true if the specified node is expanded.
     94   bool IsExpanded(ui::TreeModelNode* model_node);
     95 
     96   // Sets whether the root is shown. If true, the root node of the tree is
     97   // shown, if false only the children of the root are shown. The default is
     98   // true.
     99   void SetRootShown(bool root_visible);
    100 
    101   // Sets the controller, which may be null. TreeView does not take ownership
    102   // of the controller.
    103   void SetController(TreeViewController* controller) {
    104     controller_ = controller;
    105   }
    106 
    107   // Returns the node for the specified row, or NULL for an invalid row index.
    108   ui::TreeModelNode* GetNodeForRow(int row);
    109 
    110   // Maps a node to a row, returns -1 if node is not valid.
    111   int GetRowForNode(ui::TreeModelNode* node);
    112 
    113   views::Textfield* editor() { return editor_; }
    114 
    115   // View overrides:
    116   virtual void Layout() OVERRIDE;
    117   virtual gfx::Size GetPreferredSize() OVERRIDE;
    118   virtual bool AcceleratorPressed(const ui::Accelerator& accelerator) OVERRIDE;
    119   virtual bool OnMousePressed(const ui::MouseEvent& event) OVERRIDE;
    120   virtual ui::TextInputClient* GetTextInputClient() OVERRIDE;
    121   virtual void OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
    122   virtual void ShowContextMenu(const gfx::Point& p,
    123                                ui::MenuSourceType source_type) OVERRIDE;
    124   virtual void GetAccessibleState(ui::AccessibleViewState* state) OVERRIDE;
    125 
    126   // TreeModelObserver overrides:
    127   virtual void TreeNodesAdded(ui::TreeModel* model,
    128                               ui::TreeModelNode* parent,
    129                               int start,
    130                               int count) OVERRIDE;
    131   virtual void TreeNodesRemoved(ui::TreeModel* model,
    132                                 ui::TreeModelNode* parent,
    133                                 int start,
    134                                 int count) OVERRIDE;
    135   virtual void TreeNodeChanged(ui::TreeModel* model,
    136                                ui::TreeModelNode* model_node) OVERRIDE;
    137 
    138   // TextfieldController overrides:
    139   virtual void ContentsChanged(Textfield* sender,
    140                                const string16& new_contents) OVERRIDE;
    141   virtual bool HandleKeyEvent(Textfield* sender,
    142                               const ui::KeyEvent& key_event) OVERRIDE;
    143 
    144   // FocusChangeListener overrides:
    145   virtual void OnWillChangeFocus(View* focused_before,
    146                                  View* focused_now) OVERRIDE;
    147   virtual void OnDidChangeFocus(View* focused_before,
    148                                 View* focused_now) OVERRIDE;
    149 
    150   // PrefixDelegate overrides:
    151   virtual int GetRowCount() OVERRIDE;
    152   virtual int GetSelectedRow() OVERRIDE;
    153   virtual void SetSelectedRow(int row) OVERRIDE;
    154   virtual string16 GetTextForRow(int row) OVERRIDE;
    155 
    156  protected:
    157   // View overrides:
    158   virtual gfx::Point GetKeyboardContextMenuLocation() OVERRIDE;
    159   virtual bool OnKeyPressed(const ui::KeyEvent& event) OVERRIDE;
    160   virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE;
    161   virtual void OnFocus() OVERRIDE;
    162   virtual void OnBlur() OVERRIDE;
    163 
    164  private:
    165   friend class TreeViewTest;
    166 
    167   // Selects, expands or collapses nodes in the tree.  Consistent behavior for
    168   // tap gesture and click events.
    169   bool OnClickOrTap(const ui::LocatedEvent& event);
    170 
    171   // InternalNode is used to track information about the set of nodes displayed
    172   // by TreeViewViews.
    173   class InternalNode : public ui::TreeNode<InternalNode> {
    174    public:
    175     InternalNode();
    176     virtual ~InternalNode();
    177 
    178     // Resets the state from |node|.
    179     void Reset(ui::TreeModelNode* node);
    180 
    181     // The model node this InternalNode represents.
    182     ui::TreeModelNode* model_node() { return model_node_; }
    183 
    184     // Whether the node is expanded.
    185     void set_is_expanded(bool expanded) { is_expanded_ = expanded; }
    186     bool is_expanded() const { return is_expanded_; }
    187 
    188     // Whether children have been loaded.
    189     void set_loaded_children(bool value) { loaded_children_ = value; }
    190     bool loaded_children() const { return loaded_children_; }
    191 
    192     // Width needed to display the string.
    193     void set_text_width(int width) { text_width_ = width; }
    194     int text_width() const { return text_width_; }
    195 
    196     // Returns the total number of descendants (including this node).
    197     int NumExpandedNodes() const;
    198 
    199     // Returns the max width of all descendants (including this node). |indent|
    200     // is how many pixels each child is indented and |depth| is the depth of
    201     // this node from its parent.
    202     int GetMaxWidth(int indent, int depth);
    203 
    204    private:
    205     // The node from the model.
    206     ui::TreeModelNode* model_node_;
    207 
    208     // Whether the children have been loaded.
    209     bool loaded_children_;
    210 
    211     bool is_expanded_;
    212 
    213     int text_width_;
    214 
    215     DISALLOW_COPY_AND_ASSIGN(InternalNode);
    216   };
    217 
    218   // Used by GetInternalNodeForModelNode.
    219   enum GetInternalNodeCreateType {
    220     // If an InternalNode hasn't been created yet, create it.
    221     CREATE_IF_NOT_LOADED,
    222 
    223     // Don't create an InternalNode if one hasn't been created yet.
    224     DONT_CREATE_IF_NOT_LOADED,
    225   };
    226 
    227   // Used by IncrementSelection.
    228   enum IncrementType {
    229     // Selects the next node.
    230     INCREMENT_NEXT,
    231 
    232     // Selects the previous node.
    233     INCREMENT_PREVIOUS
    234   };
    235 
    236   // Row of the root node. This varies depending upon whether the root is
    237   // visible.
    238   int root_row() const { return root_shown_ ? 0 : -1; }
    239 
    240   // Depth of the root node.
    241   int root_depth() const { return root_shown_ ? 0 : -1; }
    242 
    243   // Loads the children of the specified node.
    244   void LoadChildren(InternalNode* node);
    245 
    246   // Configures an InternalNode from a node from the model. This is used
    247   // when a node changes as well as when loading.
    248   void ConfigureInternalNode(ui::TreeModelNode* model_node, InternalNode* node);
    249 
    250   // Sets |node|s text_width.
    251   void UpdateNodeTextWidth(InternalNode* node);
    252 
    253   // Invoked when the set of drawn nodes changes.
    254   void DrawnNodesChanged();
    255 
    256   // Updates |preferred_size_| from the state of the UI.
    257   void UpdatePreferredSize();
    258 
    259   // Positions |editor_|.
    260   void LayoutEditor();
    261 
    262   // Schedules a paint for |node|.
    263   void SchedulePaintForNode(InternalNode* node);
    264 
    265   // Recursively paints rows from |min_row| to |max_row|. |node| is the node for
    266   // the row |*row|. |row| is updated as this walks the tree. Depth is the depth
    267   // of |*row|.
    268   void PaintRows(gfx::Canvas* canvas,
    269                  int min_row,
    270                  int max_row,
    271                  InternalNode* node,
    272                  int depth,
    273                  int* row);
    274 
    275   // Invoked to paint a single node.
    276   void PaintRow(gfx::Canvas* canvas,
    277                 InternalNode* node,
    278                 int row,
    279                 int depth);
    280 
    281   // Paints the expand control given the specified nodes bounds.
    282   void PaintExpandControl(gfx::Canvas* canvas,
    283                           const gfx::Rect& node_bounds,
    284                           bool expanded);
    285 
    286   // Returns the InternalNode for a model node. |create_type| indicates wheter
    287   // this should load InternalNode or not.
    288   InternalNode* GetInternalNodeForModelNode(
    289       ui::TreeModelNode* model_node,
    290       GetInternalNodeCreateType create_type);
    291 
    292   // Returns the bounds for a node.
    293   gfx::Rect GetBoundsForNode(InternalNode* node);
    294 
    295   // Implementation of GetBoundsForNode. Separated out as some callers already
    296   // know the row/depth.
    297   gfx::Rect GetBoundsForNodeImpl(InternalNode* node, int row, int depth);
    298 
    299   // Returns the row and depth of a node.
    300   int GetRowForInternalNode(InternalNode* node, int* depth);
    301 
    302   // Returns the row and depth of the specified node.
    303   InternalNode* GetNodeByRow(int row, int* depth);
    304 
    305   // Implementation of GetNodeByRow. |curent_row| is updated as we iterate.
    306   InternalNode* GetNodeByRowImpl(InternalNode* node,
    307                                  int target_row,
    308                                  int current_depth,
    309                                  int* current_row,
    310                                  int* node_depth);
    311 
    312   // Increments the selection. Invoked in response to up/down arrow.
    313   void IncrementSelection(IncrementType type);
    314 
    315   // If the current node is expanded, it's collapsed, otherwise selection is
    316   // moved to the parent.
    317   void CollapseOrSelectParent();
    318 
    319   // If the selected node is collapsed, it's expanded. Otherwise the first child
    320   // is seleected.
    321   void ExpandOrSelectChild();
    322 
    323   // Implementation of Expand(). Returns true if at least one node was expanded
    324   // that previously wasn't.
    325   bool ExpandImpl(ui::TreeModelNode* model_node);
    326 
    327   // The model, may be null.
    328   ui::TreeModel* model_;
    329 
    330   // Default icons for closed/open.
    331   gfx::ImageSkia closed_icon_;
    332   gfx::ImageSkia open_icon_;
    333 
    334   // Icons from the model.
    335   std::vector<gfx::ImageSkia> icons_;
    336 
    337   // The root node.
    338   InternalNode root_;
    339 
    340   // The selected node, may be NULL.
    341   InternalNode* selected_node_;
    342 
    343   bool editing_;
    344 
    345   // The editor; lazily created and never destroyed (well, until TreeView is
    346   // destroyed). Hidden when no longer editing. We do this avoid destruction
    347   // problems.
    348   Textfield* editor_;
    349 
    350   // Preferred size of |editor_| with no content.
    351   gfx::Size empty_editor_size_;
    352 
    353   // If non-NULL we've attached a listener to this focus manager. Used to know
    354   // when focus is changing to another view so that we can cancel the edit.
    355   FocusManager* focus_manager_;
    356 
    357   // Whether to automatically expand children when a parent node is expanded.
    358   bool auto_expand_children_;
    359 
    360   // Whether the user can edit the items.
    361   bool editable_;
    362 
    363   // The controller.
    364   TreeViewController* controller_;
    365 
    366   // Whether or not the root is shown in the tree.
    367   bool root_shown_;
    368 
    369   // Did the model return a non-empty set of icons from GetIcons?
    370   bool has_custom_icons_;
    371 
    372   // Cached preferred size.
    373   gfx::Size preferred_size_;
    374 
    375   // Font used to display text.
    376   gfx::Font font_;
    377 
    378   // Height of each row. Based on font and some padding.
    379   int row_height_;
    380 
    381   // Offset the text is drawn at. This accounts for the size of the expand
    382   // control, icon and offsets.
    383   int text_offset_;
    384 
    385   scoped_ptr<PrefixSelector> selector_;
    386 
    387   DISALLOW_COPY_AND_ASSIGN(TreeView);
    388 };
    389 
    390 }  // namespace views
    391 
    392 #endif  // UI_VIEWS_CONTROLS_TREE_TREE_VIEW_VIEWS_H_
    393