Clash Royale CLAN TAG#URR8PPP

CATransaction completion being called immediately

I'm trying to execute a completion-block after my CAAnimation has finished. However, it seems that animation block is called before my animation completes. The animation still happens correctly though.

[CATransaction begin];
[self.view.layer addAnimation:self.dropAndBounceAnimation forKey:@"appearance"];
[CATransaction setCompletionBlock:completionBlock];
[CATransaction commit];


The dropAndBounceAnimation is a CAKeyFrameAnimation on position.y, with a fixed duration.

4 Answers
4

I'm not sure if this really is the correct fix, but by setting the completion-block before adding the animation for the layer, the completion-block is consistently called at the correct time.

[CATransaction begin];
[CATransaction setCompletionBlock:completionBlock];
[self.view.layer addAnimation:self.dropAndBounceAnimation forKey:@"appearance"];
[CATransaction commit];


If no animations are added before the current transaction group is committed (or the completion block is set to a different value,) the block will be invoked immediately.

view.wantsLayer = YES;

You need to set the animation block before adding the animation.

[CATransaction begin];
[CATransaction setValue:[NSNumber numberWithFloat: 1.0f] forKey:kCATransactionAnimationDuration];

[CATransaction setCompletionBlock:^
// ... whatever you want to do when the animation is complete
];

[self.googleMapsView animateToCameraPosition:[GMSCameraPosition
cameraWithLatitude:LATITUDE
longitude:LONGITUDE
zoom:ZOOM]];

[CATransaction commit];


This must trigger the completion block after the completion of that animation on the view.

Here is Swift 3.0.1, Xcode 8 version:

CATransaction.begin()

CATransaction.setCompletionBlock(
print("Transaction completed")
)

print("Transaction started")
view.layer.add(dropAndBounceAnimation, forKey: "appearance")

CATransaction.commit()


Try to start the animation asynchronously:

DispatchQueue.main.async
self.startAnimation()



because it can interfere with view drawing if you make some view setup before calling the animation.

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