Develop Reference

What's the best way to place multiple images onto the screen simultaneously?

So my app needs to have a maximum of 50 images on the screen at the same time in a FrameView, they need to be placed on top of a base image. If I put these images into drawable, the app crashes after a few images are placed with an OutOfMemoryError. But it works when I put the images in mipmap for some reason without crashing. So I placed them all into the mipmap folders. The images are VERY small too, the largest among them is 2.2 KB and the smallest is 398 bytes. The app works as intended, but performance is horrible after you place a few images onto the screen. The first few images will load quickly, but as you continue to place images onto the screen it gets progressively slower to the point where it may take multiple seconds to place the image onto the screen. I'm just using an ArrayList to put all the Drawables in, and then another ArrayList to put all the ImageViews and I load them into the view within my onTouchListener. Here's an idea. The index is used to decide which image is to be inserted:
drawableOverlays.set(index, getResources().getDrawable(R.mipmap.exampleImage, null));
imageOverlays.get(index).setImageDrawable(drawableOverlays.get(index));
frame.addView(imageOverlays.get(index));
I've also tried using Glide and Picasso and those loaded in even slower. Am I approaching this wrong? Is there a more efficient way to accomplish this?

The best way is create a RecyclerView with ImageViews as items, and then load the images with Glide or Picasso, any of those libraries will give you the best performance

Creating a Facebook-like image upload interface on Android

I'm trying to replicate the functionality of Facebook's image upload. To briefly describe it you click the Photo button from the main screen of the app you are taken to an image picker that will let you select up to 30 images. Once selected the images load in some kind of list view that allows you to add a caption, remove the image from the list, or do some other Facebook-y things. If you scroll around the list can move very quickly, and if you only have 5-10 images you generally spend little to no time waiting for items to reload.
Right now I have a recycler view and am using Picasso to load the images from disk, resize them, and then display them. This works, but it's not smooth or fast. Even if I only have five or six images loaded they don't come up instantly if I scroll from the bottom back to the top. I have tried increasing the LRU Cache size in Picasso, but that didn't do anything at all. It seems like the scaled image isn't getting cached so it has to be scaled to fit the screen width every time. That's just my guess though.
Any suggestions on how to get this to run more smoothly?

Android Volley with Image Caching

Currently I'm working with an application where one activity holds a list view with image and text for each row. I'm downloading the images using the volley. When the list view item is clicked the app will switch to a another activity with a detail view where a large version of the clicked image will show. For the both time I'm using NetworkImageView.
Images are loaded in the list view with caching. But the problem appeared on the detailed view. The images are showing from the previously loaded cache with low resolution. I want to load a good resolution image on detailed view which will cache the image separately for large view.
For the both screen image url are same. How to do that ?
Thanks in advance.

First thing is a bit obvious - make sure you images are at the wanted quality.
If that's the case, you'll probably want to load the image "manually" using the ImageLoader class, as the NetworkImageView by default, optimizes the size of the Bitmap it creates to be the size of the view itself. So what happens is, you first load the thumbnail view which is small, and the saved Bitmap is created in that size instead of the original image size. Then, when the bigger view requests the same image, the cached version is returned which is a small Bitmap, and the view scales it up, creating the low-res appearance.
Try using ImageLoader.get() with the width and height appropriate to the bigger view in the detail screen.
The other alternative is to load 2 versions of the same image.

How to recycle bitmaps shown in Gridview

I am using GridView in my app. The images for gridview are
I download them from network.
Downscale them to required size.
Write them to file,
All 3 steps are done using AsyncTask. Then I update UI. Next time when I open GridView, I simply decode it from sdcard. The image count is around 15. When I do memeinfo dumpsys on my app, my heap size keeps growing from 12 to 50. My question is , will gridview automatically recycle the bitmaps passed in adapter or we have to do for it. I get OutOfMemoryException.I see many links how to handle bitmaps efficiently including android link and I have implemented them in my app but no link explains bitmap recycle in gridview.Please help me.

Giant online image gallery - How do I avoid OutOfMemoryError?

For anyone who's wondering, the gallery is http://www.spore.com/sporepedia.
My app uses the Spore API to get the 100 newest creations, then displays them in a GridView. The text data about the creations is easy to store, but the images present a problem.
As far as I know, I can either keep the images in a Hashtable or grab them every time they are viewed. Neither of these will work - the Hashtable quickly presents an OutOfMemoryError, and the constant reloading causes a lot of load on the server and a lot of lag on the client.
Is there a better way to store the images?

First Don't get 100 at a time, there is no way your displaying 100 images in a gridview and having them be a usefully visible size. Retrieve the images asynchronously and get a screen full or a screen and a half at a time. I'm guessing you can display 6 to 9 images of a decent size per screen with supporting text/UI elements, you may even want to choose how many to display based on the handsets screensize/resolution. So you should probably be getting 9 to 12 images at a time.
Second, i don't know what resolution these images are coming in at, but it sounds like 'big'. If the API supports it receive only a thumbnail version for you grid view. If not, what i would probably do is: when you receive an image from the API, first create a new image scaled down to the size needed for your thumbnail that goes into the grid view, keep this in memory. Then create a new image scaled down to the size you would need for your 'detail' screen (if you have one) and cache this to the SD card and free it from ram as well as the original source image, this scaling should probably occur in a separate thread to avoid it impacting the responsiveness of your UI thread. Depending on the usage pattern, I would probably also cache the thumbnails to the SD card so it would be cheap to free the ram they use in onStop/onPause and reload them in onStart/onResume. IT also sounds like you downloading a 'top 100' or something of the sort. Since i wouldn't expect an entires new top 100 on every application use you could save a lot of network traffic by caching the images and information to the SD card and only downloading new entries each time the program runs.
Alternatively a process like:
Receive Image -> Scale in place to detail size -> cache detail size -> scale detail size to thumbnail size in place -> display thumbnail in gridview while caching thumbnail asynchronously
Would use even less memory since there is only ever 1 copy of the image in memory, but it would slow the response of the gridview as the image has to be scaled twice before it gets displayed. It may be fast enough to not matter or you may be able to play tricks with the grid view by having it display the large image (scaled internally) while the thumbnail is generated in the background, switching the gridview to the thumbnail when its ready. You'll just have to try it to determine if its fast enough.