I get the text form the sever like this:
test_abc
http://www.xxx.a.jpg
test_aaa
http://www.xxx.b.jpg
test_ccc
I want to split the string to ["test_abc", "http://www.xxx.a.jpg", "test_aaa", "http://www.xxx.b.jpg", "test_ccc"] and then display them in a UITableViewCell,before the images will be downloaded, I used a LoadingIndicator as placeholder, when the images will be downloaded, display the images and modify the height of the cell to display the whole images.
Can someone help me do this?
Try looking into Three20
An open source library written by the guy who wrote the official "Facebook" app for iOS. Moreover, the code of the facebook app is based on that library.
You may use SDWebImage, and you don't have to worry about cache, etc..
Web Image
This library provides a category for UIImageVIew with support for remote images coming from the web.
It provides:
An UIImageView category adding web image and cache management to the Cocoa Touch framework
An asynchronous image downloader
An asynchronous memory + disk image caching with automatic cache expiration handling
A guarantee that the same URL won't be downloaded several times
A guarantee that bogus URLs won't be retried again and again
Performances!
Related
I am newly in iOS development.I have to make an application for a car dealer in which i have to show different cars with different colors.Please tell me the best way because i have to fetch lots of images every time from the web server.How can i reduce the rendering time in fetching the images.
Please consider i am very new in ios development and need your help.
If you have any sample application please share it with me.
You can use DB to store images as BLOB and also fetch images only when there is update at server.
First, make sure you send images that are no larger than needed.
If you have a list view that shows pictures of the cars, have a webservice send you premade thumbnails that are (preferably) exactly the right size.
Second, Make sure the images are loaded separately from the data set.
The best place to do this, would be in the controllers for your UITableViewCell.
Just have your UITableViewCell start their own thread to download and display the image as soon as they come into view.
Third; caching.
Make sure you save local copies of the thumbnails, and make sure the Table View Cells search for local copies of the images, and load those instead of downloading them if they are already locally present.
you can do:-
use lazy loading
use paging
use predicates for searches
use fast enumeration
these things in general will keep your app smooth
If you are going to show images in UITableView then you can use lazy loading. It will load images only for the displayed rows and once image for any row index has been downloaded, it will not repeat downloading for that row index. So its faster and useful.
For the iPhone 5.0 (ARC) I am getting lot of image(image url's) and text data from server in a json form. My requirement is to load the first five images from the server and when the user scrolls down the next five images load and so on. I need to show it in a UITableViewCell. By doing this I can reduce the network calls and make the application faster on the device.
Currently, I am using a background thread to load images, but they continuously load in the background. I don't want to do it like this.
I strongly encourage you to use the AFNetworking framework (that is really great and complete for all network-related tasks).
It comes with a category on UIImageView that allows you to set the UIImageView's image directly from an NSURL, managing everything for you in the background, like downloading the image or fetching it from its cache, cancelling the request if you change the URL later to avoid useless requests, etc.
Then in your tableView:cellForRowAtIndexPath: you can simply write this kind of code:
[cell.imageView setImageWithURL:yourURL];
And you're done. It will work even when the recycling mechanism of the UITableView is in action when you scroll, which would be quite a pain to manage using other methods.
Take a look at SDWebImage. It's a really neat library to download images asynchronously and also caches them.
There are apps which show animating images(opposed to a static image) while downloading an image asynchronously.
Pinterest is one for example.
I wonder if this is possible with AFNetworking? or are there other libraries to do this?
Since AFNetworking is only a library for easily allow developer te grab data from the web I don't tink it will do any animation.
You could use AFNetworking to get the image from the web and write your own animation code that gets displayed when the image is downloaded. The eastiest way is to use UIView animations.
I am wondering if anyone can offer any advice towards solving this problem.
I am building an app that uses a UIScrollView with paging enabled, with each page corresponding to downloaded and parsed XML data. Part of that XML data is a URL to an image.
Now, it would take forever to load an app that downloads the image for every XML entry and then push it to the respective UIScrollView page created on runtime with the rest of the XML data.
Is there a way to be able to detect which UIScrollView page you are on and then download the image as needed and still allow the rest of the data to download at runtime?
Try to read SDWebImage or Apple's LazyTableImages
Just as referenece, I solved it by adding all of the image views into an NSArray. Using the scroll view delegate, I was able to determine which page number I was on, and translated that page number to an integer that I used to access the appropriate uiimage view located within the array.
It seems to work great!
Might you offer a better solution?
I'm making a simple rss reader for the iPhone. The feed (http://feeds.feedburner.com/foksuk/gLTI) contains a reference to images that I want to show in my TableView.
By default, as far as I understand, the iPhone only tries to load images when they are needed: it will only load the images for the rows that are displayed. Only when the user scrolls down, it will start loading the ones that need to be displayed. Right?
Now, since the images are downloaded from the web (they are not too large, but still), the scrolling of my TableView is stuttering. This is in the emulator, so on the device itself it will only be worse.
Luckily, this specific feed only lists the latest 12 entries of the blog. So I guess I should be able to first download an cache all the images, so they can be loaded from the memory, rather than from the URL.
What is the proper approach here?
I had the same problem, where my TableView would have to download each image before it displayed the cell. Like you say, it causes a big slowdown in the scrolling speed. What you need to do is download the images in the background and then insert them into the cell when they're finished downloading. This is how the app store app does it.
This post has all you need to know, including a class file you can use straight away:
http://www.markj.net/iphone-asynchronous-table-image/