X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/954b8ae60391d18b87a604e7919c87c0c6ae208b..93fa67c0e6124d2657488971800c8fd068dc0d0e:/docs/latex/wx/timer.tex?ds=sidebyside diff --git a/docs/latex/wx/timer.tex b/docs/latex/wx/timer.tex index a3d297137c..88ecf4940b 100644 --- a/docs/latex/wx/timer.tex +++ b/docs/latex/wx/timer.tex @@ -1,13 +1,34 @@ \section{\class{wxTimer}}\label{wxtimer} -The wxTimer class allows you to execute code at specified intervals. To -use it, derive a new class and override the {\bf Notify} member to -perform the required action. Start with {\bf Start}, stop with {\bf -Stop}, it's as simple as that. +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 the {\tt EVT\_TIMER} +macro to connect it to the event handler which will receive +\helpref{wxTimerEvent}{wxtimerevent} notifications. +\item Or you may use a derived class and the {\tt EVT\_TIMER} +macro to connect it to an event handler defined in the derived class. +If the default constructor is used, the timer object will be its +own owner object, since it is derived from wxEvtHandler. +\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} +\helpref{wxEvtHandler}{wxevthandler} \wxheading{Include files} @@ -15,49 +36,140 @@ Stop}, it's as simple as that. \wxheading{See also} -\helpref{::wxStartTimer}{wxstarttimer}, \helpref{::wxGetElapsedTime}{wxgetelapsedtime} +\helpref{::wxStartTimer}{wxstarttimer}, \helpref{::wxGetElapsedTime}{wxgetelapsedtime}, \helpref{wxStopWatch}{wxstopwatch} \latexignore{\rtfignore{\wxheading{Members}}} -\membersection{wxTimer::wxTimer} +\membersection{wxTimer::wxTimer}\label{wxtimerwxtimer} \func{}{wxTimer}{\void} -Constructor. +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 activated. +Destructor. Stops the timer if it is running. + +\membersection{wxTimer::GetInterval}\label{wxtimergetinterval} + +\constfunc{int}{GetInterval}{\void} + +Returns the current interval for the timer (in milliseconds). -\membersection{wxTimer::Interval} +\membersection{wxTimer::IsOneShot}\label{wxtimerisoneshot} -\func{int}{Interval}{\void} +\constfunc{bool}{IsOneShot}{\void} -Returns the current interval for the timer. +Returns {\tt true} if the timer is one shot, i.e.\ if it will stop after firing the +first notification automatically. -\membersection{wxTimer::Notify} +\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. It is called on timeout. +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::Start} +\membersection{wxTimer::SetOwner}\label{wxtimersetowner} -\func{bool}{Start}{\param{int}{ milliseconds = -1}, \param{bool}{ oneShot=FALSE}} +\func{void}{SetOwner}{\param{wxEvtHandler *}{owner}, \param{int }{id = -1}} -(Re)starts the timer. If {\it milliseconds}\/ is absent or -1, the -previous value is used. Returns FALSE if the timer could not be started, -TRUE otherwise (in MS Windows timers are a limited resource). +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. -If {\it oneShot} is FALSE (the default), the Notify function will be repeatedly -called. If TRUE, Notify will be called only once. +\membersection{wxTimer::Start}\label{wxtimerstart} -\membersection{wxTimer::Stop} +\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} + + + +\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.