Strongly retained array empty - ios

Question

I have an NSArray that I fill with SKTexture to animate an animal leaping:
#interface PSFrogNode ()
#property (strong, nonatomic) NSArray *leapFrames;
#end
#implementation PSFrogNode {
}
- (instancetype)init
{
self = [super init];
if (self) {
SKTextureAtlas *frogLeapAtlas = [SKTextureAtlas atlasNamed:kFrogLeapAtlas];
int numImages = frogLeapAtlas.textureNames.count;
NSMutableArray *tempArray = [NSMutableArray arrayWithCapacity:numImages];
for (int i=1; i <= numImages/2; i++) {
NSString *textureName = [NSString stringWithFormat:#"frogLeap%d", i];
SKTexture *temp = [frogLeapAtlas textureNamed:textureName];
[tempArray addObject:temp];
}
self.leapFrames = [NSArray arrayWithArray:tempArray];
self = [PSFrogNode spriteNodeWithTexture:[self.leapFrames objectAtIndex:0]];
[self setUserInteractionEnabled:NO];
}
return self;
}
- (void)animateFrogLeap
{
[self runAction:[SKAction animateWithTextures:self.leapFrames timePerFrame:0.09 resize:NO restore:YES]];
}
The array self.leapFrames is allocated in the init method but when the scene calls the animateFrogLeap method it's empty (meaning nil).
Why is that?

Answer 1

You want to create the array outside of the init method and then pass it in:
When creating the view
SKTextureAtlas *frogLeapAtlas = [SKTextureAtlas atlasNamed:kFrogLeapAtlas];
int numImages = frogLeapAtlas.textureNames.count;
NSMutableArray *images = [NSMutableArray arrayWithCapacity:numImages];
for (int i=1; i <= numImages/2; i++) {
NSString *textureName = [NSString stringWithFormat:#"frogLeap%d", i];
SKTexture *temp = [frogLeapAtlas textureNamed:textureName];
[images addObject:temp];
}
PSFrogNode *node = [[PSFrogNode alloc] initWithImages:images];
// Now use the node
PSFrogNode.h
-(instancetype)initWithImages:(NSArray *)images;
PSFrogNode.m
#interface PSFrogNode ()
#property (nonatomic, copy) NSArray *leapFrames;
#end
#implementation PSFrogNode
-(instancetype)initWithImages:(NSArray *)images
{
self = [self initWithTexture:[images firstObject]];
if (self) {
_leapFrames = [images copy];
[self setUserInteractionEnabled:NO];
}
return self;
}
As mentioned in my comment, the below line in your original implementation would mean that self would be reassigned, so the line before it (assigning the array to the property) would then be meaning less.
self = [PSFrogNode spriteNodeWithTexture:[self.leapFrames objectAtIndex:0]];