I would create separate images for each one:
LDPI should be 36 x 36. MDPI should be 48 x 48. TVDPI should be 64 x 64. HDPI should be 72 x 72. XHDPI should be 96 x 96. XXHDPI should be 144 x 144. XXXHDPI should be 192 x 192.
Then just put each of them in the separate stalks of the drawable folder.
You are also required to give a large version of your icon when uploading your app onto the Google Play Store and this should be
WEB 512 x 512. This is so large so that Google can rescale it to any size in order to advertise your app throughout the Google Play Store and not add pixelation to your logo.
Basically, all of the other icons should be in proportion to the ‘baseline’ icon,
MDPI at 48 x 48.
LDPI is MDPI x 0.75. TVDPI is MDPI x 1.33. HDPI is MDPI x 1.5. XHDPI is MDPI x 2. XXHDPI is MDPI x 3. XXXHDPI is MDPI x 4.
This is all explained on the Iconography page of the Android Developers website:http://developer.android.com/design/style/iconography.html