Supports all screen sizes and Android versions

I am developing an Android application and I want to use images as background for actions. I am targeting from API 8 to latest. I would like to know what is the best way to do it.

I have read Support for Multiple Screen Sizes and Support for Multiple Screens .

So, I made 4 images for each background with the following dimensions: 320x480, 480x800, 600x1024, 800x1280. First, I put the files in these folders respectively drawable-sw320dp, drawable-sw480dp, drawable-sw600dp, drawable-sw720dp

. Then I realized that this only works for Android 3.2 and up, so I needed to add small, regular, large and xlarge folders. In order not to duplicate files, I followed the ideas in this section of the first article .

Final structure:

• All images inside a folder drawable
  
  with different names for each dimension
• xml file in each of these folders: values-sw320dp, values-sw480dp, values-sw600dp, values-sw720dp, values-small, values-normal, values-large, values-xlarge
  
  

For example, for the background of the main activity, I have:

• drawable\bg_main_320.png
  
  
• drawable\bg_main_480.png
  
  
• drawable\bg_main_600.png
  
  
• drawable\bg_main_720.png
  
  
• And drawables.xml
  
  in the eight folders mentioned above.

Content drawables.xml

for folders values-sw480dp

and values-normal

:

<resources>
    <item name="bg_main" type="drawable">@drawable/bg_main_480</item> 
</resources>

      

        
        
        
      

    

I tested this in Android 2.3.7 and 4.0.3 and it works fine. However, I get this Lint warning for each image: "Found bitmap drawable res / drawable / bg_main_480.png in density folder. Problem: Ensures images are not defined in density independent portable folder." I know what this means, but I will not continue to create more images for each dp as it is pointless.

Is the structure I am using correctly? what do you suggest?