I often get asked if my externals are available for Android too. At the moment there is no official SDK for developing LiveCode externals for Android. I wrote an article for RunRev's newsletter describing the progress towards the SDK which you can read here.

Some externals that are only implemented in C or C++ can cross compile quite easily. For example, mergJSON and mergMarkdown are both available for Android. Some externals that need to use the Java APIs available on Android are also available but until the official SDK is released they will remain in beta and only be available to mergExt Complete users. These are mergAV with an implementation of a camera control, mergZXing with an implementation of a barcode reader and mergAndroid with a number of small features like external storage functions and displaying a toast.