Overview

The SPJuggler takes objects that implement SPAnimatable (e.g. SPTweens) and executes them.

A juggler is a simple object. It does no more than saving a list of objects implementing SPAnimatable and advancing their time if it is told to do so (by calling its own advanceTime: method). When an animation is completed, it throws it away.

There is a default juggler in every stage. You can access it by calling

SPJuggler *juggler = self.stage.juggler;

in any object that has access to the stage. You can, however, create juggler objects yourself, too. That way, you can group your game into logical components that handle their animations independently.

A cool feature of the juggler is to delay method calls. Say you want to remove an object from its parent 2 seconds from now. Call:

[[juggler delayInvocationAtTarget:object byTime:2.0] removeFromParent];

This line of code will execute the following method 2 seconds in the future:

[object removeFromParent];

The Sparrow blog contains three extensive articles about the juggler:

• http://www.sparrow-framework.org/2010/08/tweens-jugglers-animating-your-stage/
• http://www.sparrow-framework.org/2010/09/tweens-jugglers-an-in-depth-look-at-the-juggler/
• http://www.sparrow-framework.org/2010/10/tweens-jugglers-unleashed/