mal
Member
I'd like to change at runtime the texture of an SPImage invoking -SetTexture method but suddenly it crashes!
- (id)init
{
atlas = [SPTextureAtlas atlasWithContentsOfFile:@"marco.xml"];
marco =[SPImage imageWithTexture:[atlas textureByName:@"falling"]];
pistol=[atlas textureByName:@"pistol"];
return self;
}
-(void) action
{
[marco setTexture:pistol]; //crashes
}
(all is declared in header)
baike
Moderator
I can't see the rest of your code, but I would imagine you need to at least retain atlas, marco and pistol.
marco =[[SPImage imageWithTexture:[atlas textureByName:@"falling"]] retain];
pistol=[[atlas textureByName:@"pistol"] retain];You'll need to release them later (probably in dealloc). If self is an SPSprite, you'll probably need to be adding marco as a child and then later adding the sprite to the stage. I'd move atlas to a controller class so that it's around for as long as it's referenced and can be used by other textures.
Hi mal,
I guess that the variables you use in the init-method are member variables of the class? Then you have to either retain them or use the alloc-init calls.
- (id)init
{
if (self = [super init])
{
atlas = [[SPTextureAtlas alloc] initWithContentsOfFile:@"marco.xml"];
marco = [[SPImage alloc] initWithTexture:[atlas textureByName:@"falling"]];
pistol = [[atlas textureByName:@"pistol"] retain];
}
return self;
}
- (void)dealloc
{
[atlas release];
[marco release];
[pistol release];
[super dealloc];
}That's because only "alloc", "copy" and "retain" raise the retain count *permanently* -- the "factory methods" (like "imageWith...", "stringWith...") don't do that.
Things like [SPImage imageWith.....] are autorelease, when they are no longer needed (ie. removed from parent) they release.
This can be useful and dangerous, useful as you don't have to worry about memory management, dangerous as if you think i'll just reuse the same SPImage various points in the game just removing it and adding it as needed, you'll go to add it and it'll not be there and crash.
But you can do manual memory management like this,
[[SPImage alloc] initWith.....];
But then you manually have to keep track of it's retain count and call release on it yourself.
You can log retainCount with
NSLog(@"My /SPDisplayObject's/ retain Count is: %d", [object retainCount]);
(I think) When an objects retain count reaches 0 it is gone completely, but if you have made your -(void)dealloc; method call release on it to only lower it to a retaincount of 1 or it'll try releasing something that isn't there and crash.
Wow, that looks really cool =)
It hasn't got released yet, you never know when an autorelease object might release/not release for some reason. That's why it's dangerous to use them alot.
Just use the properties, they were intended for this.
There is nothing wrong with autoreleased objects, what you are doing here is just plain wrong.
I STRONGLY suggest the thread starter to learn OBJ-C from Apple's docs.
http://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/ObjectiveC/Introduction/introObjectiveC.html
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