Displaying Bitmaps Efficiently

Loading Large Bitmaps Efficiently
- Read Bitmap Dimensions and Type

• BitmapFactory ( decodeByteArray(), decodeFile(), decodeResource(), etc.)
• BitmapFactory.Options - Setting the inJustDecodeBounds property to true while decoding avoids memory allocation

- Load a Scaled Down Version into Memory

• it’s not worth loading a higher pixel image into memory if it will eventually be displayed in a lower pixel thumbnail 
• BitmapFactory.Options - use inSampleSize, To tell the decoder to subsample the image, loading a smaller version into memory

Processing Bitmaps Off the UI Thread
- Use an AsyncTask
        - Handle Concurrency ( when Bitmap is used in ListView, GridView )

Caching Bitmaps

1. Use a Memory Cache ( fast-loading UI can use memory and disk cache to quickly reload processed images )
• The LruCache class is well suited for Bitmap cacheing
• Keeps recently referenced objects in a strong referenced LinkedHashMap
• Evicts the least recently used member when cache memory exceeds its designated size.

Reference
1. developer.android.com
2. android-developers.blogspot ( Multithreading For Performance )