xml images are taking up too much memory - android

Question

hi i am new to android and i have come across some memory management issues whilst using xml to position and design my activity layouts. most images are around 100kb but vary in size e.g. image 1 will be 512x512, image 2 will be 120x320 etc. at the moment the images are slowing down my app's performance and sometimes crashing. Is there a way to reduce the amount of memory an image takes up on an app?

Answer 1

There's a number of steps that applications must go through in order to handle bitmaps sanely.

• Small Compressed Size. It's important to balance quality vs. file size for your on-disk (or on-wire) formats. Being able to run PNG files through a lossy pre-processor, or choosing to use WEBP/JPG where needed are critical for each image in your app. Smaller PNG Files covers this more. The problem here, however, is that this doesn't help you with in memory size. Remember when your images are loaded from disk, they are decompressed into 32 bits-per-pixel in memory (in other words, no compression).

• Compressed In Memory Format. Android provides the alternate 565 format, which uses only 16 bits per pixel, instead of the 32 bits for the 8888 format. If you're using an image that doesn't need alpha, you should consider the process discussed in Smaller Pixel Formats to leverage loading a bitmap as a 565.

• Re-Using bitmap space. Most applicaitons that use thumbnails, only really have 10-20 of them visible on screen at one time (even though there may be thousands to load). The trick here is described in Re-using bitmaps. Basically, once a thumbnail is no longer needed, you can re-use it's space for an incoming thumbnail, rather than allocating a brand new one.

• Display resolution. It makes no sense to load a 2MB image, to only display it as a thumbnail. Instead, you should be scaling the image to the resolution of what it'll display at, on the device. I discuss the most efficient way to load these images in the other SO post.

In general, Libraries like Picasso and Glide do a good job at providing APIs that make all this easier; but they are still going through these same processes under the hood.

Answer 2

You have 3 solutions you can do:

1st Solution:

Add in your AppManifest.xml in your application tag:

android:largeHeap="true"

This will try to prevent your app from causing OutOfMemoryError, but use it with caution.

Documentation: Whether your application's processes should be created with a large Dalvik heap. This applies to all processes created for the application. It only applies to the first application loaded into a process; if you're using a shared user ID to allow multiple applications to use a process, they all must use this option consistently or they will have unpredictable results. Most apps should not need this and should instead focus on reducing their overall memory usage for improved performance. Enabling this also does not guarantee a fixed increase in available memory, because some devices are constrained by their total available memory.

2nd Solution:

If your images' file size are large, you can minimize them by using this online tool: http://compresspng.com/

3rd Solution:

You can use BitmapFactory for loading your images. Here is the Android Developers documentation: http://developer.android.com/training/displaying-bitmaps/load-bitmap.html