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[wxWidgets.git] / docs / latex / wx / timer.tex

\section{\class{wxTimer}}\label{wxtimer}

The wxTimer class allows you to execute code at specified intervals. Its
precision is platform-dependent, but in general will not be better than 1ms nor
worse than 1s.

There are two different ways to use this class:

\begin{enumerate}
\item You may derive a new class from wxTimer and override the 
\helpref{Notify}{wxtimernotify} member to perform the required action.
\item Or you may redirect the notifications to any 
\helpref{wxEvtHandler}{wxevthandler} derived object by using the non default
constructor or \helpref{SetOwner}{wxtimersetowner}. Then use {\tt EVT\_TIMER} 
macro to connect it to the event handler which will receive 
\helpref{wxTimerEvent}{wxtimerevent} notifications.
\end{enumerate}

In any case, you must start the timer with \helpref{Start}{wxtimerstart} 
after constructing it before it actually starts sending notifications. It can
be stopped later with \helpref{Stop}{wxtimerstop}.

{\bf NB:} note that timer can only be used from the main thread currently.

\wxheading{Derived from}

\helpref{wxObject}{wxobject}

\wxheading{Include files}

<wx/timer.h>

\wxheading{See also}

\helpref{::wxStartTimer}{wxstarttimer}, \helpref{::wxGetElapsedTime}{wxgetelapsedtime}, \helpref{wxStopWatch}{wxstopwatch}

\latexignore{\rtfignore{\wxheading{Members}}}

\membersection{wxTimer::wxTimer}\label{wxtimerwxtimer}

\func{}{wxTimer}{\void}

Default constructor. If you use it to construct the object and don't call 
\helpref{SetOwner}{wxtimersetowner} later, you must override 
\helpref{Notify}{wxtimernotify} method to process the notifications.

\func{}{wxTimer}{\param{wxEvtHandler *}{owner}, \param{int }{id = -1}}

Creates a timer and associates it with {\it owner}. Please see 
\helpref{SetOwner}{wxtimersetowner} for the description of parameters.

\membersection{wxTimer::\destruct{wxTimer}}

\func{}{\destruct{wxTimer}}{\void}

Destructor. Stops the timer if it is running.

\membersection{wxTimer::GetInterval}{wxtimergetinterval}

\constfunc{int}{GetInterval}{\void}

Returns the current interval for the timer (in milliseconds).

\membersection{wxTimer::IsOneShot}\label{wxtimerisoneshot}

\constfunc{bool}{IsOneShot}{\void}

Returns {\tt TRUE} if the timer is one shot, i.e.\ if it will stop after firing the
first notification automatically.

\membersection{wxTimer::IsRunning}\label{wxtimerisrunning}

\constfunc{bool}{IsRunning}{\void}

Returns {\tt TRUE} if the timer is running, {\tt FALSE} if it is stopped.

\membersection{wxTimer::Notify}\label{wxtimernotify}

\func{void}{Notify}{\void}

This member should be overridden by the user if the default constructor was
used and \helpref{SetOwner}{wxtimersetowner} wasn't called.

Perform whatever action which is to be taken periodically here.

\membersection{wxTimer::SetOwner}\label{wxtimersetowner}

\func{void}{SetOwner}{\param{wxEvtHandler *}{owner}, \param{int }{id = -1}}

Associates the timer with the given {\it owner}\/ object. When the timer is
running, the owner will receive \helpref{timer events}{wxtimerevent} with
id equal to {\it id}\/ specified here.

\membersection{wxTimer::Start}\label{wxtimerstart}

\func{bool}{Start}{\param{int}{milliseconds = -1}, \param{bool }{oneShot = {\tt FALSE}}}

(Re)starts the timer. If {\it milliseconds}\/ parameter is -1 (value by default),
the previous value is used. Returns {\tt FALSE} if the timer could not be started,
{\tt TRUE} otherwise (in MS Windows timers are a limited resource).

If {\it oneShot}\/ is {\tt FALSE} (the default), the \helpref{Notify}{wxtimernotify} 
function will be called repeatedly until the timer is stopped. If {\tt TRUE},
it will be called only once and the timer will stop automatically. To make your
code more readable you may also use the following symbolic constants
\twocolwidtha{5cm}%
\begin{twocollist}\itemsep=0pt
\twocolitem{wxTIMER\_CONTINUOUS}{Start a normal, continuously running, timer}
\twocolitem{wxTIMER\_ONE\_SHOT}{Start a one shot timer}
\end{twocollist}


If the timer was already running, it will be stopped by this method before
restarting it.

\membersection{wxTimer::Stop}\label{wxtimerstop}

\func{void}{Stop}{\void}

Stops the timer.

\section{\class{wxTimerEvent}}\label{wxtimerevent}

wxTimerEvent object is passed to the event handler of timer events.

For example:

\begin{verbatim}
class MyFrame : public wxFrame
{
public:
    ...
    void OnTimer(wxTimerEvent& event);

private:
    wxTimer m_timer;
};

BEGIN_EVENT_TABLE(MyFrame, wxFrame)
    EVT_TIMER(TIMER_ID, MyFrame::OnTimer)
END_EVENT_TABLE()

MyFrame::MyFrame()
       : m_timer(this, TIMER_ID)
{
    m_timer.Start(1000);    // 1 second interval
}

void MyFrame::OnTimer(wxTimerEvent& event)
{
    // do whatever you want to do every second here
}

\end{verbatim}

\wxheading{Include files}

<wx/timer.h>

\wxheading{See also}

\helpref{wxTimer}{wxtimer}

\latexignore{\rtfignore{\wxheading{Members}}}

\membersection{wxTimerEvent::GetInterval}\label{wxtimereventgetinterval}

\constfunc{int}{GetInterval}{\void}

Returns the interval of the timer which generated this event.