The newest Photoshop CC 2014 update brings a new tool for Android and iOS Developers to extract the assets you need in the various screen resolutions. Since Adobe is always leaning towards iOS/Apple than Android the preset settings are geared toward iOS. Here is the quick 6 step workflow to make it work for Android.

1. Create your Assets for the highest resolution (xxhdpi right now) and rename all the layers to the filenames you want to give. Make sure that all you layers are vector based or converted to smart-objects
2. Resize your document to mdpi = 33% (if you start resolution was xxhdpi)
3. Then, choose File > Extract Assets (or use the keyboard shortcut Cmd + Option + Shift + W (Mac) | Ctrl + Alt + Shift + W (Win). Go into Settings and set the resolutions like this
4. Extract the assets by clicking extract
5. Go into the folder with the assets and create a drawable-mdpi folder
6. Move the mdpi assets in the root of the folder to the drawable-mdpi folder