iPhone - UITableView reload on scrolling

Question

I've a UITableView and each UITableViewCell displays a unique UIImage which is fetched from internet. As we scroll the UITableView, cells are recreated and tableView: cellForRowAtIndexPath: gets called every time to configure cells. So it loads UIImages again and again from internet and scrolling is not smooth.

The solution I found for myself right now is to create NSMutableArray of all those UIImages on ViewDidLoad then load images into UITableViewCells from that NSMutableArray which is for sure giving me smooth scrolling.

My concern with my own solution is that when I keep all UIImages in NSMutableArray and those all objects are kept in memory for as long as application runs, I am most probably making inefficient use of memory.

Is there a better, more efficient way to do this which gives me smooth scrolling as well as best memory usage?

score 1 · Answer 1 · answered Aug 08 '11 at 11:14

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I think this example will help you.. http://kosmaczewski.net/2009/03/08/asynchronous-loading-of-images-in-a-uitableview/

answered Aug 08 '11 at 11:14

PJR

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Thanks for the link... Its helpful – Atif Azad Aug 08 '11 at 11:37

score 0 · Accepted Answer · answered Aug 08 '11 at 11:14

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Cache the downloaded images on the filesystem. When loading a cell, first ensure that a cached copy of the associated image is available, then load it using [UIImage imageWithContentsOfFile:].

answered Aug 08 '11 at 11:14

Marcelo Cantos

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Thanks... how to cache images on filesystem? Can you provide a link to API? Or if it is possible to explain how to do, please explain.. – Atif Azad Aug 08 '11 at 11:21
@Atif: Download it using `NSData` and write it to "disk". See [here](http://stackoverflow.com/q/5323427/9990) for more details. – Marcelo Cantos Aug 08 '11 at 11:22

score 0 · Answer 3 · answered Aug 08 '11 at 11:14

You should go with array of image link instead of the image.
You should load image asynchronously so that it will improve performance of creation of the UITableviewCell.
Verify that you are using dequeueReusableCellWithIdentifier, it will give you the smoother scrolling.

iPhone - UITableView reload on scrolling

3 Answers3