005: Image libraries for Android

Fragmented - An Android Developer Podcast

English - April 17, 2015 14:20 - 1 hour - 43.4 MB - ★★★★★ - 53 ratings
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Previous Episode: 004: The RxJava show with Dan Lew (Part 2)

Next Episode: 006: Jake Wharton on Becoming a Better Developer and Creating Successful Open Source Projects (Part 1)

In this episode of Fragmented, Donn and Kaushik start off by discussing the tips and tricks available for efficiently loading images in an Android app. Good image libraries make use of these techniques and perform all the heavy lifting in the background. So they then discuss the different image library options available for Android developers.

Show Notes
Techniques/tips on effective image rendering in Android:
Bitmap sizes and allocation:

Displaying bitmaps efficiently [developer.android.com]
RGB_565, ARGB_888 and other different bitmap configurations[developer.android.com]
Android Camera2 apis [developer.android.com]
Chet Haase DevByte : Bitmap allocation [youtube.com] (bitmaps managed in Dalvik heap post 3.0; so large bitmaps implies large heap implies GC could happen more often)

Reuse bitmaps:

inBitmap option for Android 3.0 and later [developer.android.com]
before Android 4.4 only equal sized bitmaps with inSampleSize 1 supported[developer.android.com]
Reusing bitmap objects on Android[booking.com]

Downsample bitmaps

Load a scaled down version into memory [developer.android.com]

see code for calculateInSampleSize

Caching

Cache Algorithms - see LruCache [wikipedia.org]
LruCache object in Android [developer.android.com]
JakeWharton DiskLruCache [github.com]
Don’t use Soft or Weak References for your Caches [developer.android.com]
Android Performance Pattern DevByte - why 60fps [youtube.com]

Image libraries for Android:

Picasso by Square [github.com]

fetch introduced in V 2.5.0 (Changelog) [github.com]
Picasso doesn’t do bitmap recycling
Jake Wharton’s thoughts on Picasso not having a bitmap pool [github.com]