The official documentation states that base64 encode and decode in Android is in the Android.util package. But when you go to use it you will find it's not there!
After much searching, I confirmation Android left base64 encode and decode out of the Android.util package. So what to do? Don't worry, Robert W. Harder has but together a very fast Base64 encoding and decoding class you can include in your project. Here is how to add base64 encode and decode to your project.
Step 1. Visit Robert's website http://iharder.sourceforge.net/current/index.html and download the class file.
Step 2. The zip file you downloaded in step 1 includes the base64 class and a folder with examples and documentation.
Step 3. Copy the Base64.java class file into your project. Copy into your appropriate "src" folder.
Step 4. Refresh your project so the new file is included.
Step 5.When the Base64.java file is included in your project, you will get the following error "The declared package does not match the expected package". Fix this by opening the class file and adding a package declaration that matches your project.
Step 6. Done. Your ready to base64 encode and decode.