drawable vs. drawable-ldpi/drawable-mdpi

Question

All the Android docs mention the "drawable" directory. However, when I create an Android project in Eclipse, it doesn't create a "/res/drawable" directory, but it does create "/res/drawable-ldpi" and "/res/drawable-mdpi". I imagine those have something to do with pixel resolution, but what's exactly going on here? When I've stepped through the tutorials, I've manually created a "drawable" directory and put my resources in there, but did I need to? Do references to "/res/drawable/" work if only "drawable-{l|m}dpi" are present?

Answer 1

I believe this was added in Android 1.6. It's all explained here: http://developer.android.com/guide/practices/screens_support.html

Answer 2

Yes, you need to make a default /res/drawable directory in Eclipse.

If you want to use the -hdpi/-mdpi/-ldpi folders, then you need to make separate xml layouts to refer to them.

http://developer.android.com/guide/practices/screens_support.html

Answer 3

I assume it has something to do with how you generated the Android project. Typically mine creates an hdpi, mdpi, and ldpi folder. Basically, "drawable" is the default. If you have all of your resources in the hdpi folder, and try to run it on an ldpi device, I believe you will get an exception of some kind (I have not tested this, but I believe this to be the case). A detailed explanation of what happens without default resources is explained here.

You should keep a default collection of resources in the main "drawable" folder (that yes, you may have to create manually) just to be on the safe side, and to ensure compatibility with older versions of Android. Android will check the specific density folders first, but will roll back to the default drawable folder if it cannot find that specific resource in that density.