docs/latex/wx/timer.tex

   1 \section{\class{wxTimer}}\label{wxtimer}
   2
   3 The wxTimer class allows you to execute code at specified intervals. Its
   4 precision is platform-dependent, but in general will not be better than 1ms nor
   5 worse than 1s.
   6
   7 There are three different ways to use this class:
   8
   9 \begin{enumerate}
  10 \item You may derive a new class from wxTimer and override the
  11 \helpref{Notify}{wxtimernotify} member to perform the required action.
  12 \item Or you may redirect the notifications to any
  13 \helpref{wxEvtHandler}{wxevthandler} derived object by using the non default
  14 constructor or \helpref{SetOwner}{wxtimersetowner}. Then use the {\tt EVT\_TIMER}
  15 macro to connect it to the event handler which will receive
  16 \helpref{wxTimerEvent}{wxtimerevent} notifications.
  17 \item Or you may use a derived class and the {\tt EVT\_TIMER}
  18 macro to connect it to an event handler defined in the derived class.
  19 If the default constructor is used, the timer object will be its
  20 own owner object, since it is derived from wxEvtHandler.
  21 \end{enumerate}
  22
  23 In any case, you must start the timer with \helpref{Start}{wxtimerstart}
  24 after constructing it before it actually starts sending notifications. It can
  25 be stopped later with \helpref{Stop}{wxtimerstop}.
  26
  27 {\bf Note:} A timer can only be used from the main thread.
  28
  29 \wxheading{Derived from}
  30
  31 \helpref{wxEvtHandler}{wxevthandler}
  32
  33 \wxheading{Include files}
  34
  35 <wx/timer.h>
  36
  37 \wxheading{See also}
  38
  39 \helpref{::wxStartTimer}{wxstarttimer}, \helpref{::wxGetElapsedTime}{wxgetelapsedtime}, \helpref{wxStopWatch}{wxstopwatch}
  40
  41 \latexignore{\rtfignore{\wxheading{Members}}}
  42
  43 \membersection{wxTimer::wxTimer}\label{wxtimerwxtimer}
  44
  45 \func{}{wxTimer}{\void}
  46
  47 Default constructor. If you use it to construct the object and don't call
  48 \helpref{SetOwner}{wxtimersetowner} later, you must override
  49 \helpref{Notify}{wxtimernotify} method to process the notifications.
  50
  51 \func{}{wxTimer}{\param{wxEvtHandler *}{owner}, \param{int }{id = -1}}
  52
  53 Creates a timer and associates it with {\it owner}. Please see
  54 \helpref{SetOwner}{wxtimersetowner} for the description of parameters.
  55
  56 \membersection{wxTimer::\destruct{wxTimer}}\label{wxtimerdtor}
  57
  58 \func{}{\destruct{wxTimer}}{\void}
  59
  60 Destructor. Stops the timer if it is running.
  61
  62 \membersection{wxTimer::GetInterval}\label{wxtimergetinterval}
  63
  64 \constfunc{int}{GetInterval}{\void}
  65
  66 Returns the current interval for the timer (in milliseconds).
  67
  68 \membersection{wxTimer::IsOneShot}\label{wxtimerisoneshot}
  69
  70 \constfunc{bool}{IsOneShot}{\void}
  71
  72 Returns {\tt true} if the timer is one shot, i.e.\ if it will stop after firing the
  73 first notification automatically.
  74
  75 \membersection{wxTimer::IsRunning}\label{wxtimerisrunning}
  76
  77 \constfunc{bool}{IsRunning}{\void}
  78
  79 Returns {\tt true} if the timer is running, {\tt false} if it is stopped.
  80
  81 \membersection{wxTimer::Notify}\label{wxtimernotify}
  82
  83 \func{void}{Notify}{\void}
  84
  85 This member should be overridden by the user if the default constructor was
  86 used and \helpref{SetOwner}{wxtimersetowner} wasn't called.
  87
  88 Perform whatever action which is to be taken periodically here.
  89
  90 \membersection{wxTimer::SetOwner}\label{wxtimersetowner}
  91
  92 \func{void}{SetOwner}{\param{wxEvtHandler *}{owner}, \param{int }{id = -1}}
  93
  94 Associates the timer with the given {\it owner}\/ object. When the timer is
  95 running, the owner will receive \helpref{timer events}{wxtimerevent} with
  96 id equal to {\it id}\/ specified here.
  97
  98 \membersection{wxTimer::Start}\label{wxtimerstart}
  99
 100 \func{bool}{Start}{\param{int }{milliseconds = -1}, \param{bool }{oneShot = {\tt false}}}
 101
 102 (Re)starts the timer. If {\it milliseconds}\/ parameter is -1 (value by default),
 103 the previous value is used. Returns {\tt false} if the timer could not be started,
 104 {\tt true} otherwise (in MS Windows timers are a limited resource).
 105
 106 If {\it oneShot}\/ is {\tt false} (the default), the \helpref{Notify}{wxtimernotify}
 107 function will be called repeatedly until the timer is stopped. If {\tt true},
 108 it will be called only once and the timer will stop automatically. To make your
 109 code more readable you may also use the following symbolic constants:
 110
 111 \twocolwidtha{5cm}
 112 \begin{twocollist}\itemsep=0pt
 113 \twocolitem{wxTIMER\_CONTINUOUS}{Start a normal, continuously running, timer}
 114 \twocolitem{wxTIMER\_ONE\_SHOT}{Start a one shot timer}
 115 \end{twocollist}
 116
 117 If the timer was already running, it will be stopped by this method before
 118 restarting it.
 119
 120 \membersection{wxTimer::Stop}\label{wxtimerstop}
 121
 122 \func{void}{Stop}{\void}
 123
 124 Stops the timer.
 125
 126 \section{\class{wxTimerEvent}}\label{wxtimerevent}
 127
 128 wxTimerEvent object is passed to the event handler of timer events.
 129
 130 For example:
 131
 132 \begin{verbatim}
 133 class MyFrame : public wxFrame
 134 {
 135 public:
 136     ...
 137     void OnTimer(wxTimerEvent& event);
 138
 139 private:
 140     wxTimer m_timer;
 141 };
 142
 143 BEGIN_EVENT_TABLE(MyFrame, wxFrame)
 144     EVT_TIMER(TIMER_ID, MyFrame::OnTimer)
 145 END_EVENT_TABLE()
 146
 147 MyFrame::MyFrame()
 148        : m_timer(this, TIMER_ID)
 149 {
 150     m_timer.Start(1000);    // 1 second interval
 151 }
 152
 153 void MyFrame::OnTimer(wxTimerEvent& event)
 154 {
 155     // do whatever you want to do every second here
 156 }
 157
 158 \end{verbatim}
 159
 160 \wxheading{Derived from}
 161
 162 \helpref{wxEvent}{wxevent}
 163
 164 \wxheading{Include files}
 165
 166 <wx/timer.h>
 167
 168 \wxheading{See also}
 169
 170 \helpref{wxTimer}{wxtimer}
 171
 172 \latexignore{\rtfignore{\wxheading{Members}}}
 173
 174 \membersection{wxTimerEvent::GetInterval}\label{wxtimereventgetinterval}
 175
 176 \constfunc{int}{GetInterval}{\void}
 177
 178 Returns the interval of the timer which generated this event.
 179