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 two 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 {\tt EVT\_TIMER}
  15 macro to connect it to the event handler which will receive
  16 \helpref{wxTimerEvent}{wxtimerevent} notifications.
  17 \end{enumerate}
  18
  19 In any case, you must start the timer with \helpref{Start}{wxtimerstart}
  20 after constructing it before it actually starts sending notifications. It can
  21 be stopped later with \helpref{Stop}{wxtimerstop}.
  22
  23 {\bf NB:} note that timer can only be used from the main thread currently.
  24
  25 \wxheading{Derived from}
  26
  27 \helpref{wxObject}{wxobject}
  28
  29 \wxheading{Include files}
  30
  31 <wx/timer.h>
  32
  33 \wxheading{See also}
  34
  35 \helpref{::wxStartTimer}{wxstarttimer}, \helpref{::wxGetElapsedTime}{wxgetelapsedtime}, \helpref{wxStopWatch}{wxstopwatch}
  36
  37 \latexignore{\rtfignore{\wxheading{Members}}}
  38
  39 \membersection{wxTimer::wxTimer}\label{wxtimerwxtimer}
  40
  41 \func{}{wxTimer}{\void}
  42
  43 Default constructor. If you use it to construct the object and don't call
  44 \helpref{SetOwner}{wxtimersetowner} later, you must override
  45 \helpref{Notify}{wxtimernotify} method to process the notifications.
  46
  47 \func{}{wxTimer}{\param{wxEvtHandler *}{owner}, \param{int }{id = -1}}
  48
  49 Creates a timer and associates it with {\it owner}. Please see
  50 \helpref{SetOwner}{wxtimersetowner} for the description of parameters.
  51
  52 \membersection{wxTimer::\destruct{wxTimer}}
  53
  54 \func{}{\destruct{wxTimer}}{\void}
  55
  56 Destructor. Stops the timer if it is running.
  57
  58 \membersection{wxTimer::GetInterval}{wxtimergetinterval}
  59
  60 \constfunc{int}{GetInterval}{\void}
  61
  62 Returns the current interval for the timer (in milliseconds).
  63
  64 \membersection{wxTimer::IsOneShot}\label{wxtimerisoneshot}
  65
  66 \constfunc{bool}{IsOneShot}{\void}
  67
  68 Returns {\tt true} if the timer is one shot, i.e.\ if it will stop after firing the
  69 first notification automatically.
  70
  71 \membersection{wxTimer::IsRunning}\label{wxtimerisrunning}
  72
  73 \constfunc{bool}{IsRunning}{\void}
  74
  75 Returns {\tt true} if the timer is running, {\tt false} if it is stopped.
  76
  77 \membersection{wxTimer::Notify}\label{wxtimernotify}
  78
  79 \func{void}{Notify}{\void}
  80
  81 This member should be overridden by the user if the default constructor was
  82 used and \helpref{SetOwner}{wxtimersetowner} wasn't called.
  83
  84 Perform whatever action which is to be taken periodically here.
  85
  86 \membersection{wxTimer::SetOwner}\label{wxtimersetowner}
  87
  88 \func{void}{SetOwner}{\param{wxEvtHandler *}{owner}, \param{int }{id = -1}}
  89
  90 Associates the timer with the given {\it owner}\/ object. When the timer is
  91 running, the owner will receive \helpref{timer events}{wxtimerevent} with
  92 id equal to {\it id}\/ specified here.
  93
  94 \membersection{wxTimer::Start}\label{wxtimerstart}
  95
  96 \func{bool}{Start}{\param{int}{milliseconds = -1}, \param{bool }{oneShot = {\tt false}}}
  97
  98 (Re)starts the timer. If {\it milliseconds}\/ parameter is -1 (value by default),
  99 the previous value is used. Returns {\tt false} if the timer could not be started,
 100 {\tt true} otherwise (in MS Windows timers are a limited resource).
 101
 102 If {\it oneShot}\/ is {\tt false} (the default), the \helpref{Notify}{wxtimernotify}
 103 function will be called repeatedly until the timer is stopped. If {\tt true},
 104 it will be called only once and the timer will stop automatically. To make your
 105 code more readable you may also use the following symbolic constants
 106 \twocolwidtha{5cm}%
 107 \begin{twocollist}\itemsep=0pt
 108 \twocolitem{wxTIMER\_CONTINUOUS}{Start a normal, continuously running, timer}
 109 \twocolitem{wxTIMER\_ONE\_SHOT}{Start a one shot timer}
 110 \end{twocollist}
 111
 112
 113 If the timer was already running, it will be stopped by this method before
 114 restarting it.
 115
 116 \membersection{wxTimer::Stop}\label{wxtimerstop}
 117
 118 \func{void}{Stop}{\void}
 119
 120 Stops the timer.
 121
 122 \section{\class{wxTimerEvent}}\label{wxtimerevent}
 123
 124 wxTimerEvent object is passed to the event handler of timer events.
 125
 126 For example:
 127
 128 \begin{verbatim}
 129 class MyFrame : public wxFrame
 130 {
 131 public:
 132     ...
 133     void OnTimer(wxTimerEvent& event);
 134
 135 private:
 136     wxTimer m_timer;
 137 };
 138
 139 BEGIN_EVENT_TABLE(MyFrame, wxFrame)
 140     EVT_TIMER(TIMER_ID, MyFrame::OnTimer)
 141 END_EVENT_TABLE()
 142
 143 MyFrame::MyFrame()
 144        : m_timer(this, TIMER_ID)
 145 {
 146     m_timer.Start(1000);    // 1 second interval
 147 }
 148
 149 void MyFrame::OnTimer(wxTimerEvent& event)
 150 {
 151     // do whatever you want to do every second here
 152 }
 153
 154 \end{verbatim}
 155
 156 \wxheading{Include files}
 157
 158 <wx/timer.h>
 159
 160 \wxheading{See also}
 161
 162 \helpref{wxTimer}{wxtimer}
 163
 164 \latexignore{\rtfignore{\wxheading{Members}}}
 165
 166 \membersection{wxTimerEvent::GetInterval}\label{wxtimereventgetinterval}
 167
 168 \constfunc{int}{GetInterval}{\void}
 169
 170 Returns the interval of the timer which generated this event.
 171