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
Related
NSURL *url = [NSURL URLWithString:[self.imageArray objectAtIndex:indexPath.row]];
NSLog(#"My URL : %#",url);
NSData *data = [NSData dataWithContentsOfURL:url];
NSLog(#"New Data : %#",data);
UIImage *tmpImage = [[UIImage alloc] initWithData:data];
cell.imageView.image = tmpImage;
i think i got your problem, check this like my upload image in your project.
i also make a gif about how to add this setting in your project , just follow the step in my gif.
In my iOS7 app I have view just like profile page in any social networking site. I have a profile image in top left corner. I am fetching the image from service url and loading it to a UIImageview.
My problem is, I have to increase the size of this image view when the size of the image from service is big. And also i have to adjust other UILabels beside this image view. I am using this code to get the size of image from url:
NSURL *url = [NSURL URLWithString:path];
NSData *data = [NSData dataWithContentsOfURL:url];
UIImage *img = [[UIImage alloc] initWithData:data cache:NO];
CGSize size = img.size;
I don't know initWithData:cache: method on UIImage class, is this category thing?
Anyway you can make UIImageView dimension to fit content UIImage by [imageView sizeToFit].
If you want to adjust scale, use [UIImage imageWithData:data scale:scale].
NSString *path = #"http://www.example.com/example#x2.png"
NSURL *url = [NSURL URLWithString:path];
NSData *data = [NSData dataWithContentsOfURL:url];
UIImage *img = [[UIImage alloc] initWithData:data scale:2.0];
_imageView.image = img;
[_imageView sizeToFit];
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.
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.
NSData *imgData = [[NSData alloc] initWithContentsOfURL:[NSURL URLWithString:post.imageURL]];
UIImage *img = [[UIImage alloc] initWithData:imgData];
I have this code and imgData always gets nil. I checked post.imageURL and it returns a string which in a url format. I also replaced the string with a constant string(URL format) that I hardcoded but imgData still got null. This code runs on the background. Do you guys see any problem?
Your code looks good, are you sure your URL is valid ?
If post.imageURL is not valid, thus URLWithString: will be null and also your data.
I have tried with "http://www.google.com/intl/en_ALL/images/srpr/logo1w.png" to be sure, and it worked, so I guess the problem come from your URL.
Split your code :
NSURL *url = [NSURL URLWithString:#"http://www.google.com/intl/en_ALL/images/srpr/logo1w.png"];
NSData *imgData = [[NSData alloc] initWithContentsOfURL:url];
UIImage *img = [[UIImage alloc] initWithData:imgData];
And check the value of each of the variable.