Description:
I am working on an application which includes displaying of images present on server. I am using grid view to display the images. Now as the images are in large amount. I am confuse whether first i should save the images on sqlite.
How can i improve the performance of the application.
You can cache the images within the client side for better performance.
These links may help you, lets have a look..
Multithreading For Performance
Android Imagedownloader project on Google Code
Related
I'm currently building an app for learning purpose (new to android programming) that lets the users to upload
image to the server and watch other users images (by swipe the screen for example).
I finally succeeded to let the user upload image to the server and I was wondering how to code the part that retrieve the images from the server and present them in the app.
Assuming I have at the time million images, I don't want the app to load all the images in the same time because it will take a lot of time.
And all the guides I'v seen makes the app to load all the images at once.
So my question is what is the recommended way to do so?
Hope I was clear.
Thanks.
Let's say you have an array with a million images in your server to load in your app that will be shown in a RecyclerViewand assuming a screen can fit about 5 images.
In this case scenario a good approach would be to fetch 10 images at a time and load them in a RecyclerView. Load the first 10 images and once the user reaches the end of the scroll load some more images, add them to the previous retrieved image list, and finally update your RecyclerView to present them. With some effort you may be able to create a Facebook look alike effect.
RecyclerView has methods that will easily help you detect the end of scroll (there are plenty of ways you can find in StackOverFlow). Every time you detect an end of scroll, just upload more images.
This is one example: How to know whether a RecyclerView / LinearLayoutManager is scrolled to top or bottom?
Use FlexBox Layout for better UI Design to show images
https://github.com/google/flexbox-layout
See how this cat images are shown using FlexBox Layout
The question regarding thumbnail creation seems to get asked a great deal, and each time there seems to be a great many different solutions proposed. From my experience none of the supplied answers are actually sufficient and all seem to have their own flaws.
a) Memory issues when re-sizing
b) Performance issues / slow to render
I therefore wanted to post a question regarding a very common functional requirement that I am hoping someone can assist with.
'User generates a report using activity and takes associated photo using internal camera. The report along with the image path is saved to SQLLite database. User wants to view reports in a scrollable list view at some point in the future. Number of reports could be 1..100'
So given these requirements the questions I have are as follows
1) Given that to data I have not found a reliable / performent / memory optimised way of resizing full size images at run time to a given thumbnail, should I create a smaller image at image capture time?
2) If you need to display many items in a ListView should you use paging or should it be possible to display a 100 items in one ListView?
Thanks
Regarding number 2: What you could do is load a subset first (say the first 30, depending on your listview item size), and load the rest asynchronously and append them to your adapter. This will decrease the loading time of your screen.
1/ Why do you want to reinvent the wheel :) There are libraries that already do for you and do it well. See picasso or AQuery for instance (there are other libraries too).
Basically, they have a thumbnail cache somewhere on the SDcard/internal memory to keep last N requested thumbnails.
I don't know if you are keeping the image data within the database, in which case you may have to adapt one of those libraries to load the image data from the DB and not from a file as it is usually the case.
2/ Why do you want to reinvent the wheel :) There are libraries that already do for you and do it well. See https://github.com/commonsguy/cwac-endless for instance (and google for more)
I'm making an android app, here the images are getting from Cloud, is it good idea to download images and save it & use it further. Or download images every-time user uses the app, what idea you prefer is the best?
Because downloading images always is slow & its bad i know but at some point if the images are updated then how to get to know about it?
You should definitely cache your downloaded files!
Do it in your internal app directory where only you do have access to (or otherwise external storage, thats still ok).
Bandwidth and connections are always expensive and should kept low as much as possible.
So your user can see images fast even on a bad connection and your app doesn't waste his valuable bandwidth of a users data plan.
Maybe this could also help you:
https://github.com/novoda/ImageLoader
http://www.androidhive.info/2012/07/android-loading-image-from-url-http/
Make it easy on yourself and use something like Android Smart Image View. It takes care of loading and caching, and it's just about a drop-in replacement for Android's ImageView. Universal Image Loader is another alternative, more configurable, but not as quick to implement.
I used https://github.com/nostra13/Android-Universal-Image-Loader
but I think you not want only download and cache.
these no trick ,if you want check weather the image update or not, you can add metadata for image, just like md5 .
in html and browser, you can set expires header for a image:
enter link description here
but in android app, you control all yourself.
Downloading images and saving them is probably the best way to do it because you don't want to download the same images over and over. If the images are updated you can delete the older one and download the new ones. Just make sure you don't download/save a million images. Take a look at this library. It has a built-in cache on sdcard/external sd.
Downloading images from the net for display, with possible requirement of caching is a very common problem that many people have solved, you can try these solutions to see which fits you:
Ion (https://github.com/koush/ion) - very flexible and feature complete, plus it can download more than images but JSON, Strings, Files, and Java types as well. The part that I really like about this is that it can automatically cancel operations when the calling Activity finishes, so users don't waste time & bandwidth downloading images that will no longer be displayed
Universal Image Loader (https://github.com/nostra13/Android-Universal-Image-Loader) - equally capable for most use cases but for downloading/caching images only
Hi and happy new year!
I'm trying to download images from internet and put them into different ImageViews. The ImageViews are dynamically created as the user scrolls. When user arrives to the bottom of the scrollview, I load 10 images more.
The images are loading ok, but when i have a lot of images I get a java.lang.OutOfMemoryError.
I know the problem is that I have a lot of images consuming a lot of memory, so... what's the way to go on my scenario?
Thanks!
Try using a ListView instead of a ScrollView. Then you can use a lazy loading technique like Universal Image Loader. The ListView utilizes view recycling which will be easier on your memory, and you can also cache images using the image loader. This library also has a few options for memory management as well.
You are going to have to keep track of the images you have loaded and start recycling them when they are out of view.
You might find the LruCache a valuable tool. There was a good talk at IO12 "Doing More With Less: Being a Good Android Citizen" that went over lots of memory issues and includes some discussion on how to use the LruCache starting around the 4 minute mark.
This could potentially be a duplicate but I after spending several hours reading about ImageView, ImageSwitcher, Gallery Views, Lazy Loads, and more I decided I should just ask.
I am working on an app and in one of the screens there may be an image or multiple images associate with what I am talking about. The other data for this intent will be pulled from a local database. In the database it will also have a list of URLs of images that are associate with each thing that I am discussing. So I would like to know the best way to display a thumbnail of these pictures (if there are any) on the screen. Then if these pictures are clicked on it can open up the bigger version of these pictures. I don't necessarily want to download these pictures since I don't want to save them locally for the app. Plus I don't want to make the page delay in loading while it waits to download the pictures.
What is the best way to handle this scenario?
I have to caution you, that with newer versions of Android, applications can't make connections to the internet that build the UI directly on the UI thread. Instead, it must be accomplished in a background thread such as ASyncTask. So if you're going to go with making ImageViews without src in your XML, that's fine, but you can't just have the ImageViews go download their images via URL in the onCreate of your main activity any longer. It has to be done in the background, else you'll get an error.
It makes the process fairly more complex, to be honest, but it does improve application responsiveness.
For now, since images aren't the main focus of my app, I decided to just embed a webview in my page and then display the image in some custom html ( I had a list of URLs to the images online). I also calculate the width of the screen and then I adjust how wide the images are going to be in my html.
This was the easiest since the webview takes care of the "threaded" part and I don't have to worry about how to handle/save/and display the images.
It would have been helpful to see a best practices guide when it comes to android and handeling images.