The below code successfully get the image from the link and stores into my cache directory. But I want to get many(like 100) images from different url(but on the same website, only the filename differs). This works fine for taking those images but i need to wait for a long time. is there anyway to get the images easily and make my responsive time really faster.
NSString *UCIDLink = [NSString stringWithFormat:#"http://www.example.com/picture.png];
NSURL * imageURL = [NSURL URLWithString:UCIDLink];
NSData * imageData = [NSData dataWithContentsOfURL:imageURL];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
NSString *filePath = [[paths objectAtIndex:0] stringByAppendingPathComponent:[NSString stringWithFormat:#"picture.png"]];
NSError *writeError = nil;
[imageData writeToFile:filePath options:NSDataWritingAtomic error:&writeError];
if (writeError) {
NSLog(#"Success");
}else{
NSLog(#"Failed");
}
ghgh
The code you are using take time to load image contents. so, prefer to load image asynchronously.
use below code:
dispatch_queue_t q = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0ul);
dispatch_async(q, ^{
/* Fetch the image from the server... */
NSData *data = [NSData dataWithContentsOfURL:url];
UIImage *img = [[UIImage alloc] initWithData:data];
dispatch_async(dispatch_get_main_queue(), ^{
/* This is the main thread again, where we set the tableView's image to
be what we just fetched. */
cell.imgview.image = img;
});
});
or you can use:
AsyncImageView *asyncImageView = [[AsyncImageView alloc]initWithFrame:CGRectMake(30,32,100, 100)];
[asyncImageView loadImageFromURL:[NSURL URLWithString:your url]];
[YourImageView addSubview:asyncImageView];
[asyncImageView release];
Download the Files from here.....
https://github.com/nicklockwood/AsyncImageView
Use multi-threading in order to make a number of image fetches happen simultaneously. That way, you can reduce your waiting time a lot.
Related
I have a web service and I make HTTP calls to it from cocoa using this line of code:
NSData *imageData = [[NSData alloc] initWithContentsOfUrl:url options: NSDataReadingUncached error:&error];
Sometimes is it take 10 seconds, sometimes 30 seconds to load the picture from this URL.
I tried loading this URL from a normal browser and it takes 1-2 seconds.
I'm doing lazy loading and the problem is the time it takes to load the contents of this URL vs a normal browser. Both tests were done from the same network.
Download.m
NSError *error;
NSData *imageData = [[NSData alloc] initWithContentsOfURL:self.photoRecord.URL options:NSDataReadingUncached error:&error];
NSMutableArray *jsonArray = [NSJSONSerialization JSONObjectWithData:imageData options:NSJSONReadingAllowFragments error:&myError];
NSMutableDictionary *pictureInfo = [jsonArray objectAtIndex:0];
NSString *picture;
picture = [pictureInfo valueForKey:#"Picture"];
NSData *base64Data = [[NSData alloc]initWithBase64Encoding:picture];
if (base64Data) {
UIImage *downloadedImage = [UIImage imageWithData:base64Data];
self.photoRecord.image = downloadedImage;
}
[(NSObject *)self.delegate performSelectorOnMainThread:#selector(imageDownloaderDidFinish:) withObject:self waitUntilDone:NO];
Then on the main thread PictureController.m:
-(void) loadScrollViewWithPage:(NSUInteger)page{
....
NSIndexPath *myIndexPath = [NSIndexPath indexPathForRow:page inSection:0];
[self startOperationsForPhotoRecord:aRecord atIndexPath:myIndexPath];
}
- (void)startOperationsForPhotoRecord:(PictureRecord *)record atIndexPath:(NSIndexPath *)indexPath {
Download *imageD = [[Download alloc] initWithPhotoRecord:record atIndexPath:indexPath delegate:self];
[self.pendingOperations.downloadsInProgress setObject:imageD forKey:indexPath];
[self.pendingOperations.downloadQueue addOperation:imageD];
}
Then I have the delegate method to update the UIImageView when the download is done which is working just fine.
The size of the content being loaded is around 400kb.
Any ideas?
Please try to understand my question.
i am picking images from phone library and saving into Documents Directory. But When I pick large number of images the utilised memory increases gradually and reach above of 400 mb then my app crash. Please if anybody can solve my problem what should I do? I'm new comer to Objective C. Any response will be appreciated.
here is my code
when Picker finish picking
- (void)agImagePickerController:(AGImagePickerController *)picker didFinishPickingMediaWithInfo:(NSArray *)info {
[self ShowLoadingView:#"Files Are Loading...."];
[self performSelectorInBackground:#selector(saveAllSelectedImages:) withObject:info];}
and then I save images to Directory
-(void) saveAllSelectedImages:(NSArray*)imagesArray{
for (int i=0; i<imagesArray.count; i++) {
ALAsset *asset = [imagesArray objectAtIndex:i];
ALAssetRepresentation *alassetRep = [asset defaultRepresentation];
NSDate *currentDate = [NSDate date];
NSString* DucPath = [[AppDelegate GetDocumentDirectoryPath] stringByAppendingPathComponent:#"Media"];
if (![[NSFileManager defaultManager] fileExistsAtPath:DucPath])
[[NSFileManager defaultManager] createDirectoryAtPath:DucPath withIntermediateDirectories:NO attributes:nil error:nil];
if ([[asset valueForProperty:ALAssetPropertyType] isEqualToString:ALAssetTypeVideo])
{
long long DataSize = [alassetRep size];
Byte *buffer = (Byte*)malloc(DataSize);
NSUInteger buffered = (NSUInteger)[alassetRep getBytes:buffer fromOffset:0.0 length:alassetRep.size error:nil];
NSData *videoData = [NSData dataWithBytesNoCopy:buffer length:buffered freeWhenDone:YES];
NSString* newVideoName = [NSString stringWithFormat:#"video_%d_%d.mov",(int)currentDate,i];
NSString* newVideoPath = [DucPath stringByAppendingPathComponent:newVideoName];
[videoData writeToFile:newVideoPath atomically:YES];
[pImageMediaArray addObject:newVideoName];
}
else
{
UIImage *image = [UIImage imageWithCGImage:[alassetRep fullResolutionImage]];
/************************************Full Resolution Images ******************************************/
NSData *imageData = UIImageJPEGRepresentation(image, 0.8);
image = nil;
NSString *originalPath = [NSString stringWithFormat:#"IMAGE_%d_%d.jpg",(int)currentDate,i];
NSString* pImagePath = [DucPath stringByAppendingPathComponent:originalPath];
[imageData writeToFile:pImagePath atomically:YES];
[pImageMediaArray addObject:originalPath];
}
/************************************Low Resolution Images ******************************************/
UIImage *image = [UIImage imageWithCGImage:[alassetRep fullResolutionImage]];
UIImage *thumbImage = [self imageWithImage:image scaledToSize:CGSizeMake(50, 50)];
NSData *thumbImageData = UIImageJPEGRepresentation(thumbImage, 0.8);
NSString *thumbOriginalPath = [NSString stringWithFormat:#"SMALL_IMAGE_%d_%d.jpg",(int)currentDate,i];
NSString* thumbImagePath = [DucPath stringByAppendingPathComponent:thumbOriginalPath];
NSLog(#"Image path At Save Time:%#",thumbImagePath);
[thumbImageData writeToFile:thumbImagePath atomically:YES];
[pMediaArray addObject:thumbOriginalPath];
}
[appDelegate setPMediaArray:pImageMediaArray];
[pGridView reloadData];
imagesArray = nil;
[imagesArray release];
[pImageMediaArray release];
[self performSelectorOnMainThread:#selector(closeLoadindView) withObject:nil waitUntilDone:YES];}
Byte *buffer = (Byte*)malloc(DataSize);
is not being freed?
I had the same exact same issue. What worked for me was to use an autorelease pool block when you save the image. This will free up the retain count and the garbage collection will release the memory appropriately instead of retaining those objects in memory until the containing loop is finished running.
Example: In the method that you are using to save the images add code that looks like this:
#autoreleasepool {
NSString *filePath = [[NSArray arrayWithObjects:self.imagePath, #"/", GUID, #".png", nil] componentsJoinedByString:#""];
NSData *imageData = [NSData dataWithData:UIImagePNGRepresentation(image)];
BOOL res = [imageData writeToFile:filePath atomically:YES];
imageData = nil;
}
You need to add the autoreleasepool for task that perform in the background. In the above code content of the saveAllSelectedImages should be written inside autoreleasepool, Otherwise memory won't be released.
I´m designing a new app for an iPad. This app will work with a barcode scanner, and when it scans a code, it will show an image asociated.
I was thinking to build that asociating de barcode to an image name for example:
- Barcode 09090909 will show 09090909.png picture
- Barcode 19191919 will show 19191919.png picture
....
I think that there is no problem with that, but the problem comes when I need to add new barcode/pictures to the app. How can I send a new picture to my App? I see that when you develop on XCode and build you App, all the data goes into de App.
Any help or clue? thanks in advance
You can simple load them on the fly from your server, but then a network connection is required. To load them async from an server you can use this code:
dispatch_queue_t image_queue = dispatch_queue_create("com.company.app.imageQueue", NULL);
dispatch_queue_t main_queue = dispatch_get_main_queue();
dispatch_async(image_queue, ^{
NSString *URLString = #"http://example.com/images/19191919.png";
NSData *imageData = [NSData dataWithContentsOfURL:[NSURL URLWithString:URLString];
UIImage *image = [UIImage imageWithData:imageData];
dispatch_async(main_queue, ^{
[imageView setImage:image];
});
});
If you want you can also save the image to the cache dir (using the document dir is not recommended because it will collide with Apples iOS Data Storage Guidelines) and check before downloading an image twice, then the code will look like this:
NSString *fileName = #"19191919.png";
NSString *URLBaseString = #"http://example.com/images/";
NSString *URLString = [URLBaseString stringByAppendingString:fileName];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
NSString *cachePath = [paths objectAtIndex:0];
NSString *dataPath = [cachePath stringByAppendingPathComponent:fileName];
NSFileManager *fileManager = [NSFileManager defaultManager];
if ( [fileManager fileExistsAtPath:dataPath] )
{
UIImage *image = [UIImage imageWithContentsOfFile:dataPath];
[imageView setImage:image];
}
else
{
dispatch_async(image_queue, ^{
NSData *imageData = [NSData dataWithContentsOfURL:[NSURL URLWithString:URLString];
UIImage *image = [UIImage imageWithData:imageData];
[UIImagePNGRepresentation(image) writeToFile:dataPath atomically:YES];
dispatch_async(main_queue, ^{
[imageView setImage:image];
});
});
}
This code has not been tested, but should work. Note that I'm relying on ARC to manage memory.
I'm using the following code to fetch some images, that are going into a tableview. But it takes ages (5-6 seconds) to get the 30 images in.
Is there a smarter/faster way to do this?
NSString *imageUrl = ......;
NSString *urlStr =
[imageUrl UrlstringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSString *path = [[NSString alloc] initWithFormat:#"http://xxx.dk/xml.aspx%#", urlStr];
NSURL *url = [NSURL URLWithString:path];
NSData *data = [NSData dataWithContentsOfURL:url];
UIImage *img = [[UIImage alloc] initWithData:data];
return img;
[..... release];
Here profileimg is an get from Api ,String name
NSString *profileimg=[Check objectForKey:#"IMAGE"];
imageview.image=[[UIImage alloc] initWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:profileimg]]];
I'd rather download every new image in array of images when a cell appears on the screen and just display already saved image if a cell appears on the screen for the second time (i.e. image for this cell has been already downloaded).
use asynchronize loading of image.
check out this sample code : http://developer.apple.com/library/ios/#samplecode/LazyTableImages/Introduction/Intro.html
I'm trying to get an image from an URL and it doesn't seem to be working for me. Can someone point me in the right direction?
Here is my code:
NSURL *url = [NSURL URLWithString:#"http://myurl/mypic.jpg"];
NSString *newIMAGE = [[NSString alloc] initWithContentsOfURL:url
encoding:NSUTF8StringEncoding error:nil];
cell.image = [UIImage imageNamed:newIMAGE];
When I debug the newIMAGE string is nil so something isn't working there.
What you want is to get the image data, then initialize a UIImage using that data:
NSData * imageData = [[NSData alloc] initWithContentsOfURL: [NSURL URLWithString: #"http://myurl/mypic.jpg"]];
cell.image = [UIImage imageWithData: imageData];
[imageData release];
As requested, here's an asynchronous version:
dispatch_async(dispatch_get_global_queue(0,0), ^{
NSData * data = [[NSData alloc] initWithContentsOfURL: [NSURL URLWithString: #"http://myurl/mypic.jpg"]];
if ( data == nil )
return;
dispatch_async(dispatch_get_main_queue(), ^{
// WARNING: is the cell still using the same data by this point??
cell.image = [UIImage imageWithData: data];
});
[data release];
});
Ok there's a couple of things wrong here:
The conversion from URL (url) to NSString (newImage) is incorrect, what the code actually does there is try to load the contents of "http://myurl/mypic.jpg" into the NSString.
The -imageNamed method takes a string that is a path of a local file, not a URL as an argument.
You need to use an NSData object as an intermediary, like in this example:
http://blogs.oreilly.com/digitalmedia/2008/02/creating-an-uiimage-from-a-url.html
the accepted answer asynchronous version worked very slow in my code. an approach using NSOperation worked light years faster. the code provided by Joe Masilotti --> objective - C : Loading image from URL? (and pasted below):
-(void) someMethod {
// set placeholder image
UIImage* memberPhoto = [UIImage imageNamed:#"place_holder_image.png"];
// retrieve image for cell in using NSOperation
NSURL *url = [NSURL URLWithString:group.photo_link[indexPath.row]];
[self loadImage:url];
}
- (void)loadImage:(NSURL *)imageURL
{
NSOperationQueue *queue = [NSOperationQueue new];
NSInvocationOperation *operation = [[NSInvocationOperation alloc]
initWithTarget:self
selector:#selector(requestRemoteImage:)
object:imageURL];
[queue addOperation:operation];
}
- (void)requestRemoteImage:(NSURL *)imageURL
{
NSData *imageData = [[NSData alloc] initWithContentsOfURL:imageURL];
UIImage *image = [[UIImage alloc] initWithData:imageData];
[self performSelectorOnMainThread:#selector(placeImageInUI:) withObject:image waitUntilDone:YES];
}
- (void)placeImageInUI:(UIImage *)image
{
[self.memberPhotoImage setImage:image];
}
In Swift 3 and 4
let theURL = URL(string:"https://exampleURL.com")
let imagedData = NSData(contentsOf: theURL!)!
let theImage = UIImage(data: imagedData as Data)
cell.theImageView.image = theImage
This will be done in the main thread.
And to perform the same in asynchronous/background thread
DispatchQueue.main.async(){
let theURL = URL(string:"https://exampleURL.com")
let imagedData = NSData(contentsOf: theURL!)!
let theImage = UIImage(data: imagedData as Data)
}
cell.theImageView.image = theImage
Updating upon Jim dovey answer,[data release] is no longer required because in the updated apple guidelines. Memory management is done automatically by ARC (Automatic counting reference) ,
Here is the updated asynchronous call,
dispatch_async(dispatch_get_global_queue(0,0), ^{
NSData * data = [[NSData alloc] initWithContentsOfURL: [NSURL URLWithString: #"your_URL"]];
if ( data == nil )
return;
dispatch_async(dispatch_get_main_queue(), ^{
self.your_UIimage.image = [UIImage imageWithData: data];
});
});