smtk::task::Active Class Reference

This object provides applications a way to change and observe the active task. More...

#include <Active.h>

Classes
struct	Internal

Public Types
using	Observer = std::function< void(smtk::task::Task *, smtk::task::Task *)>
	The signature for observers of the active task. More...
using	Observers = smtk::common::Observers< smtk::task::Active::Observer >
	The container for registered observers.

Public Member Functions
	smtkTypeMacroBase (smtk::task::Active)
	Active (smtk::task::Instances *instances=nullptr)
	Construct an active-task tracker.
smtk::task::Task *	task () const
	Return the active task (or nullptr if no task is active).
bool	switchTo (smtk::task::Task *)
	Change the active task (or abandon the currently-active task by passing nullptr). More...
Observers &	observers ()
	Return the set of active-task observers (so you can insert yourself).
const Observers &	observers () const

Detailed Description

This object provides applications a way to change and observe the active task.

If passed an smtk::task::Manager::Instances object at construction, only managed tasks may be active. This ensures that before a task is destroyed this object can notify observers the active task is becoming inactive.

If not passed an smtk::task::Manager::Instances object at construction, any task may become active but unmanaged tasks might be deleted without any notification that the active task changed. You are strongly encouraged to pass Instances to the constructor.

Member Typedef Documentation

Observer

using smtk::task::Active::Observer = std::function<void(smtk::task::Task*, smtk::task::Task*)>

The signature for observers of the active task.

Observers are passed the previously-active task and the soon-to-be-active task.

Note that either task may be null (i.e., it is possible to have no active task).

Member Function Documentation

switchTo()

bool smtk::task::Active::switchTo

(

smtk::task::Task *

task

)

Change the active task (or abandon the currently-active task by passing nullptr).

This method returns true if the active task changed and false otherwise. Passing a task that is not managed by instances passed to the constructor will always return false. Passing a task that is already active or unavailable will return false.

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The documentation for this class was generated from the following files:

• /home/docs/checkouts/readthedocs.org/user_builds/smtk/checkouts/latest/smtk/task/Active.h
• /home/docs/checkouts/readthedocs.org/user_builds/smtk/checkouts/latest/smtk/task/Active.cxx