I receive Image from URL by threading .
but memory leaking in NSData.
Why? How do I fix it?
Leaking in Iphone devie not in simulator. help me!!
//viewcontroller
-(void)viewDidLoad
{
[self performSelectorInBackground:#selector(loadImageScreenshot:) withObject:args];
}
// loding image
-(void) loadImageScreenshot:(NSDictionary *) args
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
UIImage * screenshotImage=[UIImage imageWithStringURL:url];
NSDictionary *args2=[NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithInt:num], #"screenNum",
screenshotImage,#"image",
nil];
[self performSelectorOnMainThread:#selector(assignImageToScreenshotImageView:) withObject:args2 waitUntilDone:YES];
[pool release];
}
//image add
- (void) assignImageToScreenshotImageView:(NSDictionary *)arg
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
UIImage * image= [arg objectForKey:#"image"];
UIImageView *imageview=[UIImageView alloc]init];
.
.
imageview.image=image;
[self.mScreenshotSpace addSubview:imageview];
[imageview release];
[pool release];
}
//image from url
+(UIImage *)imageWithStringURL:(NSString *)strURL
{
NSURL *url =[NSURL URLWithString:strURL];
NSData * data=[[NSData alloc]initWithContentsOfURL:url options:NSDataReadingUncached error:&error];
UIImage * image=[UIImage imageWithData:data ];
[data release];
return image;
}
How do you know it is leaking? You are creating an autorelease pool in - (void) assignImageToScreenshotImageView:(NSDictionary *)arg that is never drained, that is a leak.
Otherwise the code seems fine.
Related
I have a url which contain image address, i want to load that image via NSThread but i am facing problem. I am doing thing like this.
imageView = [[UIImageView alloc] initWithFrame:CGRectMake(20, 10, 55, 57)];
[NSThread detachNewThreadSelector:#selector(showImage) toTarget:self withObject:nil];
[self.view addSubview:imageView];
- (void) showImage {
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
NSURL *url = [NSURL URLWithString:temp.strUrl];
UIImage *chart = [UIImage imageWithData:[NSData dataWithContentsOfURL:url]];
[url release];
imageView.image = chart;
[pool release];
}
Please help me on that.
the problem is here.
[url release];
you are not supposed to release the url object . as you haven't alocated it, may be that is what you are facing problem with.
- (void)request:(FBRequest *)request didLoad:(id)result {
// NSArray *resultData = [result objectForKey:#"data"];
NSMutableArray *photos = [[NSMutableArray alloc] initWithCapacity:1];
// imageArray = [[NSMutableArray alloc] initWithCapacity:1];
NSArray *resultData = [result objectForKey:#"data"];
if ([resultData count] > 0)
{
noOfImages = 0;
for (NSUInteger i=0; i<[resultData count] ; i++)
{
[photos addObject:[resultData objectAtIndex:i]];
NSDictionary *albumPhotos = [photos objectAtIndex:i];
NSString *imageUrl = [albumPhotos objectForKey:#"picture"];
NSLog(#"ImageURL:%#",imageUrl);
NSURL *url = [NSURL URLWithString:imageUrl];
// [slideImageArray addObject:url];
NSData *data = [NSData dataWithContentsOfURL:url];
UIImage *images = [UIImage imageWithData:data];
// imageView.image = images;
[slideImageArray addObject:images];
[NSThread detachNewThreadSelector:#selector(startTheBackgroundJob:) toTarget:self withObject:images];
}
NSLog(#"ImageCount:%d",[slideImageArray count]);
if([slideImageArray count] == 1)
{
imageView.image = [slideImageArray objectAtIndex:0];
}
if([slideImageArray count]>1)
{
numTimer =0;
myTimer = [NSTimer scheduledTimerWithTimeInterval:3 target:self selector:#selector(timerRunning) userInfo:nil repeats:YES];
}
}
}
- (void)request:(FBRequest *)request didFailWithError:(NSError *)error {
NSLog(#"Err message: %#", [[error userInfo] objectForKey:#"error_msg"]);
NSLog(#"Err code: %d", [error code]);
}
- (void)startTheBackgroundJob:(UIImage *)img
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
// wait for 3 seconds before starting the thread, you don't have to do that. This is just an example how to stop the NSThread for some time
//imageView.image = img;
noOfImages++;
// [NSThread sleepForTimeInterval:3];
// [slideImageArray addObject:img];
//[NSThread sleepForTimeInterval:1];
imageView.image = img;
if(noOfImages == 1)
{
NSLog(#"noValueif:%d",noOfImages);
// imageView.image = [slideImageArray objectAtIndex:0];
[NSThread sleepForTimeInterval:1];
// imageView.image = img;
}
else if(noOfImages >1)
{
NSLog(#"noValue:%d",noOfImages);
// numTimer =0;
// myTimer = [NSTimer scheduledTimerWithTimeInterval:3 target:self selector:#selector(timerRunning) userInfo:nil repeats:YES];
// imageView.image = img;
[NSThread sleepForTimeInterval:3];
}
// [self performSelectorOnMainThread:#selector(changeImageViewImage) withObject:nil waitUntilDone:NO];
[pool release];
}
I have to run a background thread for getting image from Facebook album .i have to start a slide show with the first image collected.and i given a sleep for 3 second but it is not working.Also is there any other method for getting image from url other than the NSData *data = [NSData dataWithContentsOfURL:url]; method
Did you ever find the answer for this question?? or were u able to solve it?
And for this facebook api, are you using a personalized subclass of NSThread or using Dispatch queues?
And to answer your question if you want to fetch data in the background use performSelectorONMainThread... some facebook SDK methods require to be runned on the main thread for them to work, in my personal experience i found out that most of the data requesting is necessary to be on the mainthread using this method.
It worked for me, hopefully it works for you
:).
Incorrect decrement of the reference count of an object that is not owned at this point by the caller on iPhone. It is happening with NSString which I clearly init and release within the for loop. I have tried to do the same as an autoreleases string but I get leaks. I assume the culprit is the stringbytrimming call. Any suggestions, by the way this does not leak, but I get the warning in build and analyze. Everything also works fine and the app does not crash.
for(int i=0;i<storyQuantity;i++) {
NSString *imageString = [[NSString alloc] init];
imageString = [[[storiesArray objectAtIndex:i] objectForKey: #"image"] stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]]; // must add trimming to remove characters
imageLoader *imageOperation = [[imageLoader alloc] initWithImageURL:imageString target:self action:#selector(didImageLoad:) number:i];
AppDelegate_iPad *appDelegate = [[UIApplication sharedApplication] delegate];
[appDelegate.queue_ addOperation:imageOperation];
[imageOperation release];
[imageString release];
}
UPDATE - added my imageLoader class, which to the best of my knowledge does not have a leak
- (id)initWithImageURL:(NSString *)url target:(id)target action:(SEL)action number:(int)number {
if(self = [super init]) {
_action = action;
_target = target;
_number = number;
if(url == nil) {
return nil;
} else {
_imgURL = [[NSURL alloc] initWithString:[url copy]];
}
}
return self;
}
- (id)main {
NSAutoreleasePool *pool = [NSAutoreleasePool new];
if ([self isCancelled]) {
NSLog(#"OPERATION CANCELLED");
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
[pool drain];
return nil;
} else {
[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
NSData *imgData = [[NSData alloc] initWithContentsOfURL:_imgURL];
UIImage *image = [[UIImage alloc] initWithData:imgData];
[imgData release];
if ([self isCancelled]) {
NSLog(#"OPERATION CANCELLED");
[image release];
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
[pool drain];
return nil;
} else {
NSNumber *tempNumber = [NSNumber numberWithInt:_number];
NSDictionary *tempDict = [NSDictionary dictionaryWithObjectsAndKeys:tempNumber, #"number", image, #"image", nil];
[image release];
if([_target respondsToSelector:_action])
[_target performSelectorOnMainThread:_action withObject:tempDict waitUntilDone:NO];
}
}
[pool drain];
return nil;
}
- (void)dealloc {
[_imgURL release];
[super dealloc];
}
Since you are reassigning the imageString variable, the reference to the original object is lost. Why allocate an empty string anyway? Just change the code to
NSString *imageString = [[[storiesArray objectAtIndex:i] objectForKey: #"image"]
stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
and remove the [imageString release] and you're good to go.
Don't track reference counts as a way into understanding memory management. It's only going to confuse you. Things manipulate your objects' reference counts from deep in the framework, and if you watch those numbers jump around for (apparently) no reason, you'll just go insane and post a series of increasingly crazy questions here, which we'll then have to deal with. Believe me--we've seen it before.
So just ignore the reference count number, and make sure you're retaining and releasing objects properly.
I'm trying to create thumbnails (288x288) of selected photos from iPad photo library. I have an array of ALAsset objects presented in a UITableView and as I select a row, a larger preview (288x288) of that image is displayed. In order to prevent main thread blocking, I'm trying to create the thumbnail on a background thread and also cache a copy of the thumbnail to the file system.
In a view controller when a tableview row is selected, I call loadPreviewImage in background:
- (void)tableView:(UITableView *)tableView
didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
// get the upload object from an array that contains a ALAsset object
upload = [uploads objectAtIndex:[indexPath row]];
[self performSelectorInBackground:#selector(loadPreviewImage:)
withObject:upload];
}
I pass a custom upload object that contains asseturl property:
- (void)loadPreviewImage:(MyUploadClass*)upload
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
UIImage *preview = [upload previewImage];
[self performSelectorOnMainThread:#selector(setPreviewImage:)
withObject:preview
waitUntilDone:YES];
[pool release];
}
This is called on main thread to display the thumbnail after it's loaded:
- (void)setPreviewImage:(UIImage*)image
{
self.imageViewPreview.image = image;
[self layoutSubviews];
}
This is a method of MyUploadClass:
- (UIImage *)previewImage
{
__block UIImage *previewImage = [[UIImage imageWithContentsOfFile:
[self uploadPreviewFilePath]] retain];
if (previewImage == nil && asseturl)
{
ALAssetsLibrary* library = [[ALAssetsLibrary alloc] init];
[library assetForURL:self.asseturl resultBlock:^(ALAsset *asset)
{
ALAssetRepresentation *rep = [asset defaultRepresentation];
previewImage = [UIImage imageWithCGImage: [rep fullScreenImage]];
previewImage = [[previewImage resizedImageWithContentMode:UIViewContentModeScaleAspectFit
bounds:CGSizeMake(288, 288)
interpolationQuality:kCGInterpolationHigh] retain];
NSData *previewData = UIImageJPEGRepresentation(previewImage, 1.0);
[previewData writeToFile:[self uploadPreviewFilePath] atomically:YES];
}
failureBlock:^(NSError *error){ }];
[library release];
}
return [previewImage autorelease];
}
The problem is that I always get nil previewImage the first time and only after the thumbnail is cached I get an image object. What am I doing wrong? Is there a better approach to this problem?
I didn't clearly understand how the resultBlock of ALAssetsLibrary operates, my mistake was to think that the execution is linear. It turns out that in my case the resultBlock executes on the main thread while the rest of the code in previewImage executes on a background thread. I was getting nil because previewImage returned before resultBlock had a chance to end its execution. I solved the problem by replacing previewImage with the following method:
- (void) loadPreviewImage:(CGSize)size withTarget:(id)target andCallback:(SEL)callback
{
NSString *path = [self uploadPreviewFilePath];
UIImage *previewImage = [UIImage imageWithContentsOfFile:path];
if (previewImage == nil && asseturl)
{
ALAssetsLibrary* library = [[ALAssetsLibrary alloc] init];
[library assetForURL:self.asseturl resultBlock:^(ALAsset *asset)
{
if (asset) {
ALAssetRepresentation *rep = [asset defaultRepresentation];
UIImage *img = [UIImage imageWithCGImage: [rep fullScreenImage]];
img = [img resizedImageWithContentMode:UIViewContentModeScaleAspectFit
bounds:size interpolationQuality:kCGInterpolationHigh];
NSData *previewData = UIImageJPEGRepresentation(img, 1.0);
[previewData writeToFile:path atomically:YES];
[target performSelectorOnMainThread:callback
withObject:img
waitUntilDone:YES];
}
}
failureBlock:^(NSError *error){ }];
[library release];
}
else {
[target performSelectorOnMainThread:callback withObject:img waitUntilDone:YES];
}
}
I'm loading images with this class. I need help on how to stop them from loading when dealloc is called. This class is extending UIImageView. Also any other advice for designing the class is appreciated, i'll want for example to dispatch the loaded bytes.
#implementation RCPhoto
- (id)initWithFrame:(CGRect)frame delegate:(id)d {
if ((self = [super initWithFrame:frame])) {
// Initialization code
delegate = d;
self.contentMode = UIViewContentModeScaleAspectFit;
}
return self;
}
- (void)dealloc {
[super dealloc];
}
#pragma mark Load photo
- (void)loadImage:(NSString *)path {
// Create a new thread for loading the image
[NSThread detachNewThreadSelector:#selector(load:)
toTarget:self
withObject:path];
}
- (void)load:(NSString *)path {
// You must create a autorelease pool for all secondary threads.
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
//NSLog(#"RCPhoto loadImage into a new thread: %#", path);
NSURL *url = [NSURL URLWithString: path];
NSData *data = [NSData dataWithContentsOfURL: url];
UIImage *image = [[UIImage alloc] initWithData: data];
[self performSelectorOnMainThread: #selector(performCompleteEvent:)
withObject: image
waitUntilDone: NO];
[pool release];
}
- (void)performCompleteEvent:(UIImage *)image {
//NSLog(#"RCPhoto finish loading");
[self setImage:image];
self.opaque = YES;
if ([delegate respondsToSelector:#selector(onPhotoComplete)]) {
[delegate performSelector:#selector(onPhotoComplete)];
}
}
#end
dataWithContentsOfURL: is designed to block until it times out or finishes receiving a complete response. You seem interested in interrupting the background thread when its associated view is deallocated. These facts are fundamentally at odds.
If you want to terminate the request as quickly as possible when your object is going away, this can be done by making an asynchronous request with NSURLConnection and canceling it in your dealloc method. If it isn't canceled before the response is received, you'll get a callback to connectionDidFinishLoading: on your delegate, at which point you can reconstitute your UIImage from the received data.
Final code:
- (void)loadImage:(NSString *)path {
imageData = [[NSMutableData data] retain];
NSURL *url = [NSURL URLWithString: path];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
connection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:YES];
}
- (void)connectionDidFinishLoading:(NSURLConnection *)conn {
UIImage *image = [[UIImage alloc] initWithData:imageData];
[self setImage:image];
self.opaque = YES;// explicitly opaque for performance
[image release];
}