Develop Reference

Load asynchronous images in listView only on scroll

So I've got this ListView and its adapter. It's using lazy loading of images with a transition effect from previous image to new.
It works great, but I have a problem and it's that my only reason to use a lazy load is to make scroll smooth. If I need to resort the listview I don't want images to lazy load as the transition is completely unnecessary.
I really don't know how to know inside the adapter whether the user is scrolling or the listview has been resorted. Any help is welcome, I found similar questions but none addressed this issue.

The concept of LazyLoading is that it loads the images for the first transition only and the images are cached. If the user again scrolls or if the ListView restores, it never downloads it again, images are taken from the local cache present on the device.
There are many Libraries that provide this feature :
Lazy List
Universal Loader
Volley
Picasso
Tutorial

Android cache webview images?

I've Listview activity each row content webview and the webview content article html code with images.
So far everything is perfect, but my problem is if the listview scrolled the webview lost images and reopen them again, and the listview become crazy.
I want to cachewebview images to prevent it to reopen or download the images again. How?
I am new in Android and sorry for my English.
Any advice?
This is my webview settings:
holder.message.addJavascriptInterface(new test_js(context), "Android");
holder.message.getSettings().setJavaScriptEnabled(true);
// holder.message.getSettings().setCacheMode(WebSettings.LOAD_DEFAULT);
holder.message.getSettings().setTextSize(WebSettings.TextSize.NORMAL);
//test
holder.message.getSettings().setCacheMode(WebSettings.LOAD_CACHE_ELSE_NETWORK);
holder.message.getSettings().setAppCacheMaxSize( 8 * 1024 * 1024 ); // 8MB
holder.message.getSettings().setAppCachePath(context.getApplicationContext().getCacheDir().getAbsolutePath());
holder.message.getSettings().setAllowFileAccess(true);
holder.message.getSettings().setAppCacheEnabled(true);
but it won't cache the images it's redownloading them again when I scroll the listview!

I recommend you to use Universal-Image-Loader for loading and caching images when working with listview or recyclerview. The Universal-Image-Loader has option delayBeforeLoading(time) to prevent listview's scroll issues when there is item with images. And to cache other content just write the body of response to file and extract it to your listview.

Keep the images downloaded in the listview during scrolling

I'm developing my first app and have been reading a LOT here.
I've been trying to find a solution for the following issue for over a week with no luck.
I have an Adapter that extends ArrayAdapter to show image and 3 lines of text in each row.
Inside the getView I assign relevant information for the TextViews and use ImageLoader class to download image and assign it to the ImageView.
Everything works great! I have 4.5 rows visible on my screen (out of total of 20). When I scroll down for the first time the images continue to download and be assigned in right order to the list.
BUT when I scroll back the list looses all the images and start redrawing them again (0.5-1 sec per image) in correct order. From what I've been reading it's the standard list performance but I want to change it.
I want that, once the image was downloaded, it will be "sticked" to the list for the whole session of the current window. Just like in Contacts list or in the Market. It is only 20 images (6-9kb each).
Hope I managed to explain myself.

you need to cache each image after download it, and each time the adapter need it check if its already downloaded get it from cache (disk or memory) otherwise download it.
at first i recommended you to read this tutorial from android dev site http://developer.android.com/training/displaying-bitmaps/cache-bitmap.html
or use an external lib like this one https://github.com/koush/UrlImageViewHelper

The problem here is that the ArrayAdapter is reusing the list view rows as you scroll, so as you scroll down, the top row will be reused and inserted at the bottom of the list (for performance reasons).
Your best bet here is to try to cache the images locally on your device to avoid calling the ImageLoader every time.
One pretty good library that solves this problem is ignition. It's open source and available here: https://github.com/kaeppler/ignition
Take a look at RemoteImageView for a good example of the caching mechanism.

Loading pictures in Android

What is the best practice for loading images from the Web into a ListView?
Do I have to load them first into SQLite database or should I load them directly into a ListView?
And also after clicking an item in the ListView I have to show the same image in another activity. Is it the right way to pass this image to another activity or it is better to load it from Web / SQLite once again?

Look here Lazy loading of images
Loading them directly into the listview will make scrolling in it slow, as it will reload them everytime they get visible.

do that Google recommended http://developer.android.com/training/displaying-bitmaps/index.html

Android ListView with an incrementally built ListAdapter

I am trying to figure out the right architecture for a list view that loads information from an http endpoint. My problem is that the information to be displayed has both text and image content. If I only load the text content the the UI is very responsive but if I also load the image content then it takes a few seconds for the list to be populated. I parse the content as it comes in and build up a list adapter but what I want to do is build up the list adapter incrementally so that the user sees the information as it becomes available instead of waiting until the last item is processed before any information is displayed. Currently I do everything with the help of AsyncTask so I'm aware of threads and how they can be helpful so I'd like to know how other people have worked around the issue of displaying list based information as quickly as possible.

So this solution doesn't incrementally build the ListView but if the text information comes quickly as you mentioned I think it might help:
Lazy load of images in ListView
Basically this solution will place a stub image in the ImageView until the desired image is finished downloading.

It is not only about loading images as far as i understand your question. Please look at "Implementing a Dynamically Loading Adapter (Endless List)" tutorial: http://codinglines.frankiv.me/post/14552677846/android-implementing-a-dynamically-loading-adapter