Xamarin SpriteKit running action with key - ios

Question

I am using SpriteKit with Xamarin. I'm currently making a game similar to flappy bird, except the pipes can also 'chomp' down and kill you like that. So at any given time my pipe sprites can be running two actions, one for movement along the X axis (when the player is moving) and one for movement along the Y axis (closing the pipes). When the player stops moving along the X axis I want to stop the running action of the pipes that moves them horizontally, but still keep the chomping action going. I'm having trouble setting up a key for my action though. Currently, this is what I have.
public override void TouchesEnded (NSSet touches, UIEvent evt)
{
base.TouchesEnded (touches, evt);
//TODO: Optimize by removing action by key instead of all of them. Figure out how to do this and impliment.
//This needs to be done before refining chomp as it will flow into the chomp logic
//by not stopping a chomp mid-way because the player lifted their finger.
poletop.RemoveAllActions();
polebottom.RemoveAllActions();
pole2top.RemoveAllActions ();
pole2bottom.RemoveAllActions ();
background.RemoveAllActions ();
//restarting the chomping action if it was stopped before.
chomped_return (false);
chomped_return (true);
}
So I'm basically stopping all actions, then restarting only the chomp if it was running (gets restarted in chomped_return).
This isn't very efficient and also causes some lag in-game as it stops and starts.
Code for starting the action along the X axis (player movement). This is the SKAction that I want to have the key so I can stop it and it alone. resetpoles is the completion function.
SKAction movebottompole;
SKAction movetoppole;
movebottompole = SKAction.MoveToX (edgebottom.X, flTime);
movetoppole = SKAction.MoveToX (edgetop.X, flTime);
polebottom.RunAction (movebottompole, resetpoles);
poletop.RunAction(movetoppole, resetpoles);
Chomping down on the player is an instant teleport of the pipes, but here's the code that runs to start the action of the pipes returning to their original position along the Y axis. This is setting up the action that I don't want to stop until it has completed.
public void chomped_return(bool blFirstPole)
{
//define our two actions
SKAction topreturn;
SKAction botreturn;
//define our floats for the time calculation
float flTime = 0;
float flMoveSpeed = 750;
float flDistance = 0.0f;
if (blFirstPole == true)
{
flDistance = (float)polebottom.Position.Y;
}
else if (blFirstPole == false)
{
flDistance = (float)pole2bottom.Position.Y;
}
//calculate time based on distance and vector units/second desired.
flTime = flDistance / flMoveSpeed;
//setup our moveto actions and use the time calculated above. Start the action.
topreturn = SKAction.MoveToY (750.0f, flTime);
botreturn = SKAction.MoveToY (0.0f, flTime);
if (blFirstPole == true)
{
poletop.RunAction (topreturn);
polebottom.RunAction (botreturn);
}
else if (blFirstPole == false)
{
pole2top.RunAction (topreturn);
pole2bottom.RunAction (botreturn);
}
return;
}
The variable blFirstPole is used to determine whether or not we are running the action on the first set of poles or second set (as there can be two on screen at once)
Would really appreciate any assistance, if you need any more information please do let me know!
Thanks

Answer 1

You can use RemoveActionForKey to remove an action with an certain key.
https://developer.xamarin.com/api/member/MonoTouch.SpriteKit.SKNode.RemoveActionForKey/p/System.String/
polebottom.RunAction(movebottompole, "movebottompole");
// remove it
polebottom.RemoveActionForKey("movebottompole");
But now you don't have your completion handler anymore. You can solve it by combining these two actions into one Sequence.
var poleactionWithCompletion = SKAction.Sequence(movebottompole, restpoles);
polebottom.RunAction(poleactionWithCompletion, "movebottompole");
If you need this more often, you can implement an extension method like:
public static class SKNodeExtension
{
public static void RunAction(this SKNode node, SKAction action, SKAction completion, string key)
{
var sequence = SKAction.Sequence(action, completion);
node.RunAction(sequence, key);
}
}
and then run your action like:
polebottom.RunAction(movebottompole, restpoles, "movebottompole");