I see this output in allocations tool(one of too many warnings) Can anyone tell me what is going bad here? something with the UIImage and something very wrong with how I create/use navigation controller
And this is my category for imageview in APP_CATEGORIeS class import
#implementation UIImage(APP)
+(UIImage *) APP_IMAGE_BCKGROUND {
NSString *path = [[NSBundle mainBundle] pathForResource:#"bckPhone" ofType:#"png"];
return [UIImage imageWithContentsOfResolutionIndependentFile:path];
}
Looks like you have a UIImage in a past view that wasn't released that's causing dirty leak. Make sure your view transitions are smooth (allocations wise).
On a separate note, if you're setting two different anImageView images and it's retained in another class then Xcode and the compiler might not be catching it and warning you, however that'll do nasty things when the code is executed.
Related
I have written code that when you hit button, it opens new screen with image on it. On that new screen there is button that dismisses screen, and returns to main screen. And it works fine if i do it like this (no leaks etc...):
img = [UIImage imageNamed: #"Galaxy"];
ImageDisplay *display = [[ImageDisplay alloc] initWithImage:img];
But if i replace this line of code with something like this:
img = [[UIImage alloc] initWithContentsOfFile:[[NSBundle mainBundle] pathForResource:#"Minnesota" ofType:#"png"]];
ImageDisplay *display = [[ImageDisplay alloc] initWithImage:img];
[img release];
It acts as i have memory leak. Every time i open image screen, app takes more and more memory. But all deallocs are called, even [img retainCount] shows 1 before final release. Is there possibility that there is a bug here, because i cant find whats wrong?
EDIT:
Here is dealloc method for ImageDisplay, and this method gets called:
-(void) dealloc {
[img release];
[super dealloc];
}
Your ImageDisplay *display is retaining the image. As it should be. When you release that, it should release all its retained entities. In the code you've shown, you're not releasing it. The typical use would be to tell the containing view controller to display it modally or something (or push it onto a navigation controller) and release it, leaving its retain lifecycle in the hands of whatever view controller is now managing it. The difference is, in your first code sample, *img is autoreleased, and will release itself when appropriate, and in the second, it's not.
ARC would save your bacon here, and dramatically simplify your code.
Also you should google the term "static method", because you're working really hard to call static methods as instances of the class of objects, which is like going around your ass to get to your elbow.
ALSO, stop looking at retainCount. All sorts of things might retain your objects under the hood of the framework. Using retainCount as part of your debugging strategy is a one way ticket to confusionville.
Try using this one instead, you dont need to allocate and release:
[UIImage imageWithContentsOfFile:(NSString *)name]
Note that since imageNamed: is a class method not an instance method, you use it like this:
UIImage *myImage = [UIImage imageNamed:#"pony.png"];
Your posted code using initWithContentsOfFile looks correct, so the leak must be somewhere in your ImageDisplay class.
I am trying to make a button in my IPhone app which changes an existing image (simple, I know! but I've spent 2 days on this :)
I have a button:
- (IBAction)myButton {
myUIImageView.image = [UIImage imageNamed:#"image.jpg"];
NSLog(#"my button");
}
I am attempting to find out why the button is not doing anything. "my button" does get logged to the console so I know its mapped correctly. Firstly, I was hoping someone could tell me if I could perhaps log some more important info here, like the image file path? Or perhaps you see why this isn't working.
I synthesize myUIImageView above this:
#synthesize myUIImageView;
And I declare it in my .h file:
- (IBAction)myButton;
#property(retain, nonatomic) IBOutlet UIImageView* myUIImageView;
Typically, something is nil here.
You have
myUIImageView.image = [UIImage imageNamed:#"image.jpg"];
So the obvious suspects would be either:
myUIImageView is nil, or
[UIImage imagedNamed:#"image.jpg"] is returning nil.
Add some logging to see if either of those is true.
NSLog(#"imageView: %#, image resource: %#", myUIImageView, [UIImage imageNamed:#"image.jpg"]);
If the image isn't being loaded, then I would expect for you to see a change in the UI, so that's probably not the issue.
More likely is that the nib outlet for myUIImageView haven't been wired up correctly in Interface Builder, but the logging should point you in the right direction.
Two things to try:
Make sure that your UIImageView is
actually being displayed. Do do this, just set its background color to something
visible, e.g.,
myUIImageView.backgroundColor =
[UIColor redColor];.
Make sure that your image file
("image.jpg") is part of your
project.
I've got a fairly simple app that has the following in the view the program is mostly in:
int currentPageIndex;
NSArray *images;
NSString *nextImage;
IBOutlet UIImageView *firstPage;
IBOutlet UIButton *bigButton;
In the implementation viewDidLoad, I load the array with a bunch of image file names:
images = [NSArray arrayWithObjects:#"image1.jpg", #"image2.jpg", etc, nil];
[images retain];
Each time the bigButton is tapped, the image changes:
- (IBAction)bigButtonTapped:(id)sender {
currentPageIndex++;
nextImage = [images objectAtIndex:currentPageIndex];
firstPage.image = [UIImage imageNamed:nextImage];
}
Everything works as I want it to, except that I am getting a "Received memory warning. Level=1" in the console with my device plugged in. This warning comes up after every 12 images or so, and eventually it crashes with "EXC_BAD_ACCESS"
I thought this would actually be a good way not to put anything in memory, as there is only one UIImageView on the screen and its image is changed as I need it to be.
It is a very simple app so I'm sure the fix is very simple... any ideas what I might be overlooking? Thanks so much!!
Since you get a memory warning, the problem must be that the images aren't released. However, in the code you show, you're handling the images correctly. So the problem is most likely in a part of the code you're not showing us.
The only minor problem is see, which has been mentioned before, is that the currentPageIndex will eventually point outside of the range of the array. But this will cause a different error.
To avoid going over the size of the Array,
currentPageIndex= 0;
for(currentPageIndex in images){
doStuff;
}
OH!!!!! I THINK I spotted the your problem. Whenever you use UIImage imageNamed to load images all the images stay in memmory even though release reference to it. use the other UIImage method:contentOfFile.
One other thing, make sure your images are optimize for iOS. Use .png when posibible.
dibu2z
I assume Image is a retained property.
Try to release it at the beginning of your bigButtonTapped.
Hope it helps.
Could be that you've reached the end of the array and you're trying to access past the end of the array. You could do a
currentPageIndex++;
if ( currentPageIndex < [images count]) {
nextImage = [images objectAtIndex:currentPageIndex];
firstPage.image = [UIImage imageNamed:nextImage];
}
Also could be that the image you listed doesn't exist in the bundle.
There isn't really enough information here to say for sure what your problem is. EXC_BAD_ACCESS generally happens when you try to access an objects that has already been deallocated.
The quickest way to track down the real cause of EXC_BAD_ACCESS is by using the NSZombieEnabled executable argument, and then setting a breakpoint on objc_exception_throw. This will get you a stack trace, and allow you to determine specifically which object you are trying to access.
http://www.cocoadev.com/index.pl?NSZombieEnabled
Using Malloc to debug
I currently have this code:
UIImage *image = [[UIImage alloc] initWithContentsOfFile:[imagesPath stringByAppendingPathComponent:[NSString stringWithFormat:#"/%#.png", [postsArrayID objectAtIndex:indexPath.row]]]];
It's loading in an image to set in a UITableViewCell. This obviously leaks a lot of memory (I do release it, two lines down after setting the cells image to be that image), and I'm not sure if it caches the image at all.
Is there another way, that doesen't leak so much, I can use to load in images multiple times, like in a tableView, from the Documents-directory of my app? Thanks.
The leaks tool or Instruments should tell you what exactly is leaking. However, the image and imageView properties retain their images, so you may need to ensure you're properly releasing them in the dealloc method for the UITableViewCell. But like AngeDeLaMort said, we really need more information to give you a precise answer.
What is leaking exactly?
If you alloc an image and release it after, I don't see the leak your are talking about? Maybe more code or more precision would help.
I'm getting a EXC_BAD _ACCESS after leaving the method below. At that point htmlDocument becomes invalid, which it should since it falls out of scope. But is that why I'm getting the error? By the time the contentView (UIWebView) loads, htmlDocument is gone. But doesn't contentView already have what it needs from loadHTMLString?
- (void)viewDidLoad {
[super viewDidLoad];
//something other processing here
NSString *htmlDocument = [NSString stringWithFormat:#"<html> \n"
"<body>%#</body> \n"
"</html>", aboutContent];
[contentView loadHTMLString:htmlDocument baseURL:[NSURL URLWithString:#"http://www.abc.com"]];
}
Is there a better way to follow this all the way to failure? Leaving this method is the end of the line for my code. SDK stuff from there.
From your second post, the line you have commented out ([button release]) releases an object already marked to be released automatically.
Either remove the "autorelease" where you are doing an alloc for the button or remove the [button release] statement for the code to compile without errors and exceptions.
If an object is marked for autorelease, calling a release on it will be the same as calling a release on a deallocated instance, hence the error.
At a glance I would say there is nothing wrong with this code, assuming 'aboutContent' is a valid pointer to an object.
You can try running your app with Guard Malloc on the simulator, but that's not guaranteed to turn up anything. I'd suggest you just start commenting out statements until you find the one that's causing the error.
It's not clear what's going on with the code snippet you've just provided without more context. That said, it looks like all you want to do is load some HTML locally in the device. Why not just do this?
- (void)viewDidLoad {
[webView loadRequest:[NSURLRequest
requestWithURL:[NSURL fileURLWithPath:[[NSBundle mainBundle]
pathForResource:#"help/about.html"
ofType:#"html"]isDirectory:NO]]];
}
Using this technique, you can author HTML-based documents right in your phone without the user being wise to the fact that they are actually looking at a web view: this includes Javascript, CSS, the whole ball of a wax. I've seen people actually have their iPhone app go out to the Internet just to render a static page on the Internet which really is not necessary.
From your sample code in the second post, the button you release UIBarButtonItem *button is not retained by anything following the release you have commented out - and so it is deallocated.
You need to add the button to another view (using adSubview) in order for it to display and then you can release it. The parent view will retain the button.
Of course if you are going to refer to the button again, your view controller should keep the retain and release the button in its dealloc.