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I'm trying to setup my scene in my SpriteKit scene file (.sks). I set out my nodes as colored rectangles and using childNodeWithName works fine for deserializing into SKNode objects.

But I'm trying to deserialize into a custom subclass called BadGuyZagNode. The code builds fine but crashes at runtime.

The code:

GameScene.m

-(void)didMoveToView:(SKView *)view {
    BadGuyZagNode *badGuy = (BadGuyZagNode *)[self childNodeWithName:@"badguy"];
    [badGuy setupBadGuyZagNode];
}

BadGuyZagNode.h

@interface BadGuyZagNode : SKSpriteNode
- (void) setupBadGuyZagNode;
@end

BadGuyZagNode.m

@implementation BadGuyZagNode

- (void) setupBadGuyZagNode {
    self.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:self.frame.size];
    self.physicsBody.categoryBitMask = GMCollisionCategoryMinorBadGuy;
    self.physicsBody.collisionBitMask = GMCollisionCategoryLaser;
    self.physicsBody.contactTestBitMask = GMCollisionCategoryLaser;
    self.physicsBody.affectedByGravity = NO;
    self.physicsBody.dynamic = NO;
}

@end

The error

'NSInvalidArgumentException', reason: '-[SKSpriteNode setupBadGuyZagNode]: unrecognized selector sent to instance

Everything works if I don't use childNodeWithName and just init a spriteNodeWithColor.

I've tried adding an init method with no params and calling [super init] but that didn't fly.

I've reviewed both of these answers but neither applied:

Subclassing SKNodes created with SpriteKit .sks scene file

Subclassing SpriteKit classes in Swift

I've also watched the WWCD SpriteKit Best Practices video, but the examples don't use any custom classes.

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gmoore
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1 Answers1

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There probably isn't enough code posted to give you a more in depth answer. But the short of it is that 

[self childNodeWithName:@"badguy"];

doesn't return an instance of a BadGuyZagNode

You can validate this by doing:

BadGuyZagNode *badGuy = (BadGuyZagNode *)[self childNodeWithName:@"badguy"];
NSLog(@"badGuy is %@", NSStringFromClass([badGuy class]));

I didn't fully read Subclassing SKNodes created with SpriteKit .sks scene file, but based on the question/answer, if you want to subclass SKNodes in the SKS, you'll need to do some work (see the answer). If you are not doing this, this is why your node is not a BadGuyZagNode

I'm a little unclear you mean by

Everything works if I don't use childNodeWithName and just init a spriteNodeWithColor.

How are you calling this (i.e. show more code)?

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Mobile Ben
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  • So it sounds like you're saying "It isn't possible" which is a valid answer. I didn't know enough about SpriteKit to know if it was possible. – gmoore Dec 15 '14 at 13:05
  • I'm not saying it's impossible. But if you are using SKS right out of the box with no additional code support, then yes. I'd read http://stackoverflow.com/questions/25123264/subclassing-sknodes-created-with-spritekit-sks-scene-file. Based on that it seems feasible. The way you have your stuff set up right now, it won't work, which is why you are getting the `unrecognized selector sent to instance` error. – Mobile Ben Dec 16 '14 at 01:03