1 2 /* 3 * Copyright 2006 The Android Open Source Project 4 * 5 * Use of this source code is governed by a BSD-style license that can be 6 * found in the LICENSE file. 7 */ 8 9 10 #ifndef SkEventSink_DEFINED 11 #define SkEventSink_DEFINED 12 13 #include "SkRefCnt.h" 14 #include "SkEvent.h" 15 16 /** \class SkEventSink 17 18 SkEventSink is the base class for all objects that receive SkEvents. 19 */ 20 class SkEventSink : public SkRefCnt { 21 public: 22 23 24 SkEventSink(); 25 virtual ~SkEventSink(); 26 27 /** 28 * Returns this eventsink's unique ID. Use this to post SkEvents to 29 * this eventsink. 30 */ 31 SkEventSinkID getSinkID() const { return fID; } 32 33 /** 34 * Call this to pass an event to this object for processing. Returns true if the 35 * event was handled. 36 */ 37 bool doEvent(const SkEvent&); 38 39 /** Returns true if the sink (or one of its subclasses) understands the event as a query. 40 If so, the sink may modify the event to communicate its "answer". 41 */ 42 bool doQuery(SkEvent* query); 43 44 /** 45 * Returns the matching eventsink, or null if not found 46 */ 47 static SkEventSink* FindSink(SkEventSinkID); 48 49 protected: 50 /** Override this to handle events in your subclass. Be sure to call the inherited version 51 for events that you don't handle. 52 */ 53 virtual bool onEvent(const SkEvent&); 54 virtual bool onQuery(SkEvent*); 55 56 private: 57 SkEventSinkID fID; 58 59 // for our private link-list 60 SkEventSink* fNextSink; 61 62 typedef SkRefCnt INHERITED; 63 }; 64 65 #endif 66
