Here a free and Advanced Fast GBA for Android Devices. Many options and fast emulation speed which many other app don't provide.
This the best GB Advanced emu you'll ever find with a high game compatibility and an amazing screen layout and very Simple UI
This application is able to run all kinds of GameBoy games smoothly in your device, it doesn't require a very flagship hardware of device .
★ Super fast and smooth GBA emulation
★ High-level BIOS emulation, no BIOS file needed
★ Works in any orientation
★ Landscape or Portrait Orientation
★ Variable Scaling Modes
★ Backup memory and save state support
★ Supports games file in .gba format, optionally in ZIP, RAR, or 7Z files
★ Frame Skipping if needed
★ Custom button layout
This app does not include any ROMs but they can be downloaded from many websites as long as you already own the game.