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
Related
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
Currently I have implemented Expandable List View referencing from the following website:
http://www.androidhive.info/2013/07/android-expandable-list-view-tutorial/
Now, how do I download a jpeg from a url(e.e. h--p://www.test.com/image.jpg) and display this image within each list child when that list child is chosen? Currently it only shows data.
The reason is being, I don't want to download the images and store within the assets folder which will increase the size of the application, that's why use url to show only when that list child is chosen.
Is it possible? Or I could only do so by downloading the image beforehand and storing under assets?
Yes it is possible. If you want to implement this then you should grab a lazy loading library. For that you may use aquery just google it, its a nice library to provide the required mechanism.
Also Expandable istview is nothing but a listview so whatever you want to do inside a listviewcan be done within ExpandableListView as well.
I have created five Horizontal ListView with images and texts in one activity. Using Lazy loading of images concept it is working fine. Now when it is offline, the list is showing blank,ie., no data . I need to implement memory-caching concept, such that when it is offline it will be showing the previous session datas(images & texts).
In oncreate: I am calling the Asynctask. In doinbackground method of asynctask,I am consuming Webservices containing images & texts,then I am passing those datas to the adapter. And in postexecute, I am setting my adapter to Listview.
In adapter class: getview method I am setting the texts and loading the images using lazy loading.
Please help me to get rid of this. Thanks in advance
You should store text etc. in an SQLiteDatabase and store your Images on external storage.
I saw a lot of implementations of smooth downloading images from web and showing them in listView with cache. Now I have the following situation: I'm storing images to SDCard and sometimes my listView shows them instead of images from web resource. In this case navigation in listView is not smooth. Do you know any good implementation of listView with image from sdCard?
Multithreading is the answer!
http://android-developers.blogspot.com/2010/07/multithreading-for-performance.html
Just ignore the the sections for downloading, but idea is the same!
Then check this code :
Lazy load of images in ListView
I am making an app in which i want to show list of images in my application in the manner , as the images are shown in gallery.The images will get load dynamically. Any help regarding this will be appreciated.
You can use Android's MediaStore.images class to list all the images in the device
http://developer.android.com/reference/android/provider/MediaStore.Images.Media.html
You can get the solution from this tutorial
http://vikaskanani.wordpress.com/2011/07/20/android-custom-image-gallery-with-checkbox-in-grid-to-select-multiple/
A nice and easy tutorial here : http://www.anddev.org/a_androidwidgetgallery_-_example-t332.html
if you want to load your images dynamically, create a function in the BaseAdapter and call it into the constructor to load them at the start of the view for example...