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_COREWM_FOCUS_RULES_H_ 6 #define UI_VIEWS_COREWM_FOCUS_RULES_H_ 7 8 #include "ui/views/views_export.h" 9 10 namespace aura { 11 class Window; 12 } 13 14 namespace views { 15 namespace corewm { 16 17 // Implemented by an object that establishes the rules about what can be 18 // focused or activated. 19 class VIEWS_EXPORT FocusRules { 20 public: 21 virtual ~FocusRules() {} 22 23 // Returns true if |window| is a toplevel window. Whether or not a window 24 // is considered toplevel is determined by a similar set of rules that 25 // govern activation and focus. Not all toplevel windows are activatable, 26 // call CanActivateWindow() to determine if a window can be activated. 27 virtual bool IsToplevelWindow(aura::Window* window) const = 0; 28 // Returns true if |window| can be activated or focused. 29 virtual bool CanActivateWindow(aura::Window* window) const = 0; 30 // For CanFocusWindow(), NULL is supported, because NULL is a valid focusable 31 // window (in the case of clearing focus). 32 virtual bool CanFocusWindow(aura::Window* window) const = 0; 33 34 // Returns the toplevel window containing |window|. Not all toplevel windows 35 // are activatable, call GetActivatableWindow() instead to return the 36 // activatable window, which might be in a different hierarchy. 37 // Will return NULL if |window| is not contained by a window considered to be 38 // a toplevel window. 39 virtual aura::Window* GetToplevelWindow(aura::Window* window) const = 0; 40 // Returns the activatable or focusable window given an attempt to activate or 41 // focus |window|. Some possible scenarios (not intended to be exhaustive): 42 // - |window| is a child of a non-focusable window and so focus must be set 43 // according to rules defined by the delegate, e.g. to a parent. 44 // - |window| is an activatable window that is the transient parent of a modal 45 // window, so attempts to activate |window| should result in the modal 46 // transient being activated instead. 47 // These methods may return NULL if they are unable to find an activatable 48 // or focusable window given |window|. 49 virtual aura::Window* GetActivatableWindow(aura::Window* window) const = 0; 50 virtual aura::Window* GetFocusableWindow(aura::Window* window) const = 0; 51 52 // Returns the next window to activate in the event that |ignore| is no longer 53 // activatable. This function is called when something is happening to 54 // |ignore| that means it can no longer have focus or activation, including 55 // but not limited to: 56 // - it or its parent hierarchy is being hidden, or removed from the 57 // RootWindow. 58 // - it is being destroyed. 59 // - it is being explicitly deactivated. 60 // |ignore| cannot be NULL. 61 virtual aura::Window* GetNextActivatableWindow( 62 aura::Window* ignore) const = 0; 63 }; 64 65 } // namespace corewm 66 } // namespace views 67 68 #endif // UI_VIEWS_COREWM_FOCUS_RULES_H_ 69