iPhone App crashes after switching, possibly due to UIImage imageNamed - iphone

Question

My app moves 10 UIImageViews randomly around the screen, and once an UIImageView hits the corner, it changes its image. The problem is: after switching between apps and going back to mine, the app crashes.
The console gives me this message:
"App" exited abnormally with signal 10: Bus error
The crash log states this:
Exception Type: EXC_BAD_ACCESS (SIGBUS)
Exception Codes: KERN_PROTECTION_FAILURE at 0x0000000000000011
Crashed Thread: 0 Dispatch queue: com.apple.main-thread
I think the problem is due to the fact that I'm using UIImage imageNamed, here is the code:
In ViewController.h:
UIImage *red;
UIImage *green;
UIImage *blue;
UIImageView *ballOne;
UIImageView *ballTwo;
UIImageView *ballThree;
UIImageView *ballFour;
// And declare UIImageView for other balls
int clr
In ViewController.m:
- (void)viewDidLoad {
...
red = [UIImage imageNamed: #"redTexture.png"];
green = [UIImage imageNamed: #"greenTexture.png"];
blue = [UIImage imageNamed: #"blueTexture.png"];
...
}
- (void)moveAll:(NSTimer *)theTimer{
...
// If UIImageView touches a corner, Do this:
clr = arc4random()%3 + 1;
switch (clr) {
case 1:
[ballOne setImage:red];
break;
case 2:
[ballOne setImage:green];
break;
case 3:
[ballOne setImage:blue];
break;
default:
break;
}
// And do this for the rest of 9 "balls"
}
Why does my App crash, and how do I solve it?

Answer 1

[UIImage imageNamed:] returns an autoreleased instance of a UIImage. That means that the memory will be released as soon as the event loop ends.
Yo need to retain those instance either by calling.
[[UIImage imageNamed:#"blabl.png"] retain]
or (preferred method) by setting up your blue, red, green members as property with
#property(nonatomic, retain) UIImage* red;
and your code will be like :
- (void)viewDidLoad {
...
self.red = [UIImage imageNamed: #"redTexture.png"];
self.green = [UIImage imageNamed: #"greenTexture.png"];
self.blue = [UIImage imageNamed: #"blueTexture.png"];
...
}
Of course do not forget to release them when your done otherwize you will have the opposite of what you have now : memory leaks.
to release red, call
[red release]
inthe dealloc method.

Answer 2

A bus error means that you're attempting to access memory that the CPU physically cannot access. You probably have a stray pointer.
Maybe try the memory allocation debugger?