Timer.md

2021-03-10_10:35:35

Timer

Blueprint

Timers are created from a Blueprint's Event Graph. Create a new Timer with the Set Timer by Event and Set Timer by Function Name functions.

For Set Timer By Event, create the event that will be triggered by right-click the Event Graph background and select Add Custom Event. A Custom Event is a Node Graph execution source that can be triggered manually, for example using a Timer. Bind the Custom Event to the Timer by dragging a wire from the red square on the Custom Event node to the red square on the Set Timer by Event node. Other way is to drag from the red square on the Set Timer by Event node onto a empty space, select Create Event from the menu, and select the name of the Custom event from the new node's drop-down menu.

The Set Timer functions return a Timer Handle. That can be used to pause and unpause the timer.

[[2020-05-10_18:32:07]] Custom event

C++

This is how a Timer Delegate is used to register a timer callback in a World:

FTimerDelegate TimerCallback;
TimerCallback.BindLambda([]()
{
    // Your code here.
});

FTimerHandle Handle;
GetWorld()->GetTimerManager().SetTimer(Handle, TimerCallback, 5.0f, false);

FTimerDelegate is an type that holds a function to execute, for example a lambda. TimerCallback is an instance of the Delegate, so it holds a function to execute. FTimerHandle is a link between some delegate trigger and the delegate. SetTimer create that link, linking something inside the Timer Manager to TimerCallback, which in turn links to the function to execute. The link is remembered in Handle, so we can sever the link later if we wish.

We can also have the timer call a member function:

GetWorldTimerManager().SetTimer(Handle, this, &UMyClass::MyCallback, 5.0f, false);

The timer is cleared with

GetWorld()->GetTimerManager().ClearTimer(Handle);

[[2020-09-30_13:13:51]] Callbacks
[[2020-06-29_13:29:35]] Events
[[2020-05-10_18:32:07]] Custom event
[[2021-03-10_10:42:34]] Delegate