Best Practice when Caching files in Android

Question

I currently have my app caching image files in the cache sub-directory for the application. The images are used in a ListView and stored in a Has

Answer 1

Everyone has good ideas. I like the idea of using SoftReference's, although I'm not sure how often those get cleaned up, as this varies so much from VM to VM. You might want to combine that with regular HashMap to prevent you entire cache getting cleared every few minutes.

EclipseLink has a few different cache implementations and pretty good documentation on them. You could probably take advantage of a few ideas from the implementation (e.g., LRU, MRU, etc.). e.g.,

• hard cache
• soft cache
• combined hard/soft cache

Since you're tuning a cache down to the nitty-gritty, I would recommend tuning it to different devices based on the hard specs. This is normally bad design, but the scope of the hardware that your software runs on mandates it, IMHO. e.g.,

• Detect the amount of available memory on the SD card. Most new smart phones come with multi-GB SD cards, and those are pretty hard to fill up with regular usage for most users. Use away! You can also detect the amount of space available on the SD card on startup, and increase/decrease the size of your cache on startup.
• Detect the amount of available memory and configure your caches with that in mind. If a user is using a hardware-intensive application, I don't think they'll mind that it makes up 200MB of RAM and provides a very fast user experience, especially since they spent a lot of money to have a phone that has 1-2GB RAM.

Good luck!