You could use Google's Custom Search API, although that will cost you money per search.
You can also do something like this:
- Make an Http request to this address https://www.google.com/search?tbm=isch&q=kitten
- Write a regular expression to grab the first image's url
- Make another Http request to that url
- Read the result of the request into a byte array
- Convert the byte array to a Bitmap
- Set up an ImageView and call imgView.setImageBitmap
I'm being vague because I don't know what you've tried so far, and the actual code for this would be fairly involved.
edit: A quick search shows this relevant SO question: Google image search by image in android