Lazy adapter only on scroll

Question

Please excuse my english... I'm French :)

I write this post because I have a little problem with my Android application ! I have got a listview, with images and text, and I want to load images ONLY when the user see the items.

For example:

• We have got 1000 items in the listview
• User scroll and display item 52 to item 57.
• I want to load images for thoses items
• I want to unload (to free memory) other items

Am I clear ?

Thanks for your help !

Answer 1

Use a lazyLoader as suggested by others. Additionally, use a gesture detector/listener. Don't call getImage/Bitmap methods of ImageLoaders for getting the images when the user flings.

How can you do this ?
Set a boolean in onFling of the gesture listener method, and reset it accordingly.

What do you achieve?
When the user performs a fling operation, you skip downloading images.

Alternative Accumulate requests and download after a delay of say 700 ms. Use a FIFO collection and the max size of the collection will be equal to the number of items visible. Reset(further delay) the download request if the user scrolls.

I prefer the 1st approach. Will post some code if I get time.

Answer 2

You should create a custom listview adapter you have a lot of examples in internet, for example: asynchronous image listview or multithreading-for-performance or the thread: Load asynchronous images in listView

Answer 3

use the concept of lazyLoader as u had to add jar file of lazy loader too

in listview there is property as smoothscroll set it true.