interface/wx/timer.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        timer.h
   3 // Purpose:     interface of wxTimer
   4 // Author:      wxWidgets team
   5 // RCS-ID:      $Id$
   6 // Licence:     wxWindows licence
   7 /////////////////////////////////////////////////////////////////////////////
   8
   9 // generate notifications periodically until the timer is stopped (default)
  10 #define wxTIMER_CONTINUOUS false
  11
  12 // only send the notification once and then stop the timer
  13 #define wxTIMER_ONE_SHOT true
  14
  15 wxEventType wxEVT_TIMER;
  16
  17
  18 /**
  19     @class wxTimer
  20
  21     The wxTimer class allows you to execute code at specified intervals.
  22     Its precision is platform-dependent, but in general will not be better than
  23     @c 1ms nor worse than @c 1s.
  24
  25     There are three different ways to use this class:
  26
  27     - You may derive a new class from wxTimer and override the
  28       wxTimer::Notify member to perform the required action.
  29     - You may redirect the notifications to any wxEvtHandler derived object by
  30       using the non-default constructor or wxTimer::SetOwner.
  31       Then use the @c EVT_TIMER macro to connect it to the event handler which
  32       will receive wxTimerEvent notifications.
  33     - You may use a derived class and the @c EVT_TIMER macro to connect it to
  34       an event handler defined in the derived class. If the default constructor
  35       is used, the timer object will be its own owner object, since it is
  36       derived from wxEvtHandler.
  37
  38     In any case, you must start the timer with wxTimer::Start() after constructing
  39     it before it actually starts sending notifications.
  40     It can be stopped later with wxTimer::Stop().
  41
  42     @note A timer can only be used from the main thread.
  43
  44     @library{wxbase}
  45     @category{misc}
  46
  47     @see wxStopWatch
  48 */
  49 class wxTimer : public wxEvtHandler
  50 {
  51 public:
  52     /**
  53         Default constructor.
  54         If you use it to construct the object and don't call SetOwner() later,
  55         you must override Notify() method to process the notifications.
  56     */
  57     wxTimer();
  58
  59     /**
  60         Creates a timer and associates it with @a owner.
  61         Please see SetOwner() for the description of parameters.
  62     */
  63     wxTimer(wxEvtHandler* owner, int id = -1);
  64
  65     /**
  66         Destructor. Stops the timer if it is running.
  67     */
  68     virtual ~wxTimer();
  69
  70     /**
  71         Returns the ID of the events generated by this timer.
  72     */
  73     int GetId() const;
  74
  75     /**
  76         Returns the current interval for the timer (in milliseconds).
  77     */
  78     int GetInterval() const;
  79
  80     /**
  81         Returns the current @e owner of the timer.
  82
  83         If non-@NULL this is the event handler which will receive the
  84         timer events (see wxTimerEvent) when the timer is running.
  85     */
  86     wxEvtHandler* GetOwner() const;
  87
  88     /**
  89         Returns @true if the timer is one shot, i.e. if it will stop after firing
  90         the first notification automatically.
  91     */
  92     bool IsOneShot() const;
  93
  94     /**
  95         Returns @true if the timer is running, @false if it is stopped.
  96     */
  97     bool IsRunning() const;
  98
  99     /**
 100         This member should be overridden by the user if the default constructor was
 101         used and SetOwner() wasn't called.
 102
 103         Perform whatever action which is to be taken periodically here.
 104
 105         Notice that throwing exceptions from this method is currently not
 106         supported, use event-based timer handling approach if an exception can
 107         be thrown while handling timer notifications.
 108     */
 109     virtual void Notify();
 110
 111     /**
 112         Associates the timer with the given @a owner object.
 113
 114         When the timer is running, the owner will receive timer events (see wxTimerEvent)
 115         with @a id equal to @a id specified here.
 116     */
 117     void SetOwner(wxEvtHandler* owner, int id = -1);
 118
 119     /**
 120         (Re)starts the timer. If @a milliseconds parameter is -1 (value by default),
 121         the previous value is used. Returns @false if the timer could not be started,
 122         @true otherwise (in MS Windows timers are a limited resource).
 123
 124         If @a oneShot is @false (the default), the Notify() function will be called
 125         repeatedly until the timer is stopped.
 126         If @true, it will be called only once and the timer will stop automatically.
 127
 128         To make your code more readable you may also use the following symbolic constants:
 129         - wxTIMER_CONTINUOUS: Start a normal, continuously running, timer
 130         - wxTIMER_ONE_SHOT: Start a one shot timer
 131         If the timer was already running, it will be stopped by this method before
 132         restarting it.
 133     */
 134     virtual bool Start(int milliseconds = -1, bool oneShot = false);
 135
 136     /**
 137         Stops the timer.
 138     */
 139     virtual void Stop();
 140 };
 141
 142
 143 /**
 144    @class wxTimerRunner
 145
 146    Starts the timer in its ctor, stops in the dtor.
 147 */
 148 class wxTimerRunner
 149 {
 150 public:
 151     wxTimerRunner(wxTimer& timer);
 152     wxTimerRunner(wxTimer& timer, int milli, bool oneShot = false);
 153     void Start(int milli, bool oneShot = false);
 154     ~wxTimerRunner();
 155 };
 156
 157 /**
 158     @class wxTimerEvent
 159
 160     wxTimerEvent object is passed to the event handler of timer events
 161     (see wxTimer::SetOwner).
 162
 163     For example:
 164
 165     @code
 166     class MyFrame : public wxFrame
 167     {
 168     public:
 169         ...
 170         void OnTimer(wxTimerEvent& event);
 171
 172     private:
 173         wxTimer m_timer;
 174         wxDECLARE_EVENT_TABLE();
 175     };
 176
 177     wxBEGIN_EVENT_TABLE(MyFrame, wxFrame)
 178         EVT_TIMER(TIMER_ID, MyFrame::OnTimer)
 179     wxEND_EVENT_TABLE()
 180
 181     MyFrame::MyFrame()
 182            : m_timer(this, TIMER_ID)
 183     {
 184         m_timer.Start(1000);    // 1 second interval
 185     }
 186
 187     void MyFrame::OnTimer(wxTimerEvent& event)
 188     {
 189         // do whatever you want to do every second here
 190     }
 191     @endcode
 192
 193     @library{wxbase}
 194     @category{events}
 195
 196     @see wxTimer
 197 */
 198 class wxTimerEvent : public wxEvent
 199 {
 200 public:
 201     wxTimerEvent();
 202     wxTimerEvent(wxTimer& timer);
 203
 204     /**
 205         Returns the interval of the timer which generated this event.
 206     */
 207     int GetInterval() const;
 208
 209     /**
 210         Returns the timer object which generated this event.
 211     */
 212     wxTimer& GetTimer() const;
 213 };
 214