Nanomaps-droid is a project mainly written in Java, it's free.
Unobtrusive map library for android
This is a rough port of my nanomaps javascript library to android. It follows the same philosophy that a map library is really less about the map and more about integrating easily into the native widget environment. Most map libraries try to do everything for you. The nanomaps libraries just try to be as fast as possible doing the basics of displaying map imagery and georeferencing your views. Otherwise, they get out of the way.
The project was started on 4/2/2011, so you can get an idea of where its at.
Core rendering and IO management is mostly done and features the following:
// Parent container
FrameLayout frame=new FrameLayout(this);
// Construct the map
final MapSurface map=new MapSurface(this);
frame.addView(map, new FrameLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
map.setMapLocationZoom(Coordinate.latLng(47.616159, -122.320944), 15);
// Add tile layer using MapQuest OSM Tiles
MapTileView mtv=new MapTileView(this, new UriTileSelector("http://otile${modulo:1}.mqcdn.com/tiles/1.0.0/osm/${level}/${tileX}/${tileY}.png"));
map.getLayer(MapSurface.LAYER_MAP).addView(mtv);
// Add a shiny pink marker anchored at its bottom center
ImageView marker1=new ImageView(this);
marker1.setImageResource(R.drawable.pin_pink);
map.addOverlay(marker1, MapSurface.LAYER_OVERLAY, Coordinate.latLng(47.61402, -122.318457),
MapSurface.BIAS_CENTER, MapSurface.BIAS_BOTTOM);
attachClickEvents(map, marker1);
// Add a shiny blue orb marker anchored at its center
ImageView marker2=new ImageView(this);
marker2.setImageResource(R.drawable.orb_blue);
map.addOverlay(marker2, MapSurface.LAYER_OVERLAY, Coordinate.latLng(47.616523, -122.318407),
MapSurface.BIAS_CENTER, MapSurface.BIAS_CENTER);
// Add an "uncertainty" circle with a radius of 60m
CircleOverlay cov=new CircleOverlay(this);
cov.setRadius(60);
map.addOverlay(cov, MapSurface.LAYER_OVERLAY, Coordinate.latLng(47.615016, -122.316574));
// Add an "uncertainty circle plus heading cone" with radius
// of 120m, cone overshoot of 10px, heading of 45 degrees and uncertainty of 20 degrees
UncertaintyHeadingOverlay ohv=new UncertaintyHeadingOverlay(this);
ohv.setRadius(120);
ohv.setHeadingConeOvershoot(10);
ohv.setHeading(45, 20);
map.addOverlay(ohv, MapSurface.LAYER_OVERLAY, Coordinate.latLng(47.619095, -122.321499));
attachChangeHeadingEvents(ohv);
(MIT with additional restriction)
Copyright (c) 2010 Stella Laurenzo, http://stella.laurenzo.org
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
As an additional restriction, it is not permitted to use this software in a way that infringes on any entity's intellectual property rights (ie. make sure you have permission to display tiles and or other map related content).