SKScene runAction completion block not called - ios

Question

I am working on a sprite kit game in which I have an action called playCountdown:
SKAction *playCountdown = [SKAction performSelector:#selector(startCountdown) onTarget:self];
playCountdown works fine but when it completes, the completion block never gets called.
[self runAction:playCountdown completion:^{
NSLog(#"anything goes");
}];
Here is startCountdown for completeness:
- (void)startCountdown{
SKLabelNode *countdownLabel = [SKLabelNode labelNodeWithFontNamed:#"Arial"];
CGFloat screenHeight = [UIScreen mainScreen].bounds.size.height;
CGFloat screenWidth = [UIScreen mainScreen].bounds.size.width;
__block short countdownValue = 3;
countdownLabel.position = CGPointMake(screenWidth/2, screenHeight/2 - countdownLabel.fontSize/2);
countdownLabel.zPosition = 100.0;
countdownLabel.text = [NSString stringWithFormat:#"%d", countdownValue];
countdownLabel.fontColor = [UIColor blackColor];
countdownLabel.verticalAlignmentMode = SKLabelVerticalAlignmentModeBaseline;
[self addChild:countdownLabel];
SKAction *zoomIn = [SKAction scaleTo:1.5f duration:0.9];
SKAction *fadeOut = [SKAction fadeAlphaTo:0.0f duration:0.1];
SKAction *updateCount = [SKAction customActionWithDuration:0.0 actionBlock:^(SKNode *node, CGFloat elapsedTime) {
SKLabelNode *textNode = (SKLabelNode *)node;
countdownValue --;
if (countdownValue == 0) {
textNode.text = #"PLAY!";
}
else{
textNode.text = [NSString stringWithFormat:#"%d", countdownValue];
}
textNode.alpha = 1.0f;
textNode.xScale = 1.0f;
textNode.yScale = 1.0f;
}];
SKAction *sequence = [SKAction sequence:#[zoomIn, fadeOut, updateCount]];
SKAction *repeat = [SKAction repeatAction:sequence count:4];
[countdownLabel runAction:repeat completion:^{
[countdownLabel removeFromParent];
}];
NSLog(#"completed!");
}
I have verified that startCountdown actually reaches its end. However the completion block never gets called. Any ideas?
Thanks

Answer 1

I would recommend you verify that your code is indeed being called by creating a very simple NSLog only block.
If you are still having problems, consider using a SKAction sequence instead. This will accomplish the same thing as you are trying to do with a completion block.

Answer 2

There must be an issue with a SKAction created using a selector... The code:
SKAction *playCountdown = [SKAction performSelector:#selector(startCountdown) onTarget:self];
would execute calling:
[self runAction:playCountdown completion:^{ ... }];
although the completion block would never get called.
I have instead created the playCountdown action using a block:
SKAction *playCountdown = [SKAction runBlock:^{
[self startCountdown];
}];
and the completion block now gets called. The problem now is that the end of the playCountdown action is not "understood" by the system and the 2 actions do not run serially but almost concurrently.