Android how to uncluster on single tap on a cluster marker maps v2

    mClusterManager
            .setOnClusterClickListener(new OnClusterClickListener<MyItem>() {
                @Override
                public boolean onClusterClick(final Cluster<MyItem> cluster) {
                    map.animateCamera(CameraUpdateFactory.newLatLngZoom(
                            cluster.getPosition(), (float) Math.floor(map
                                    .getCameraPosition().zoom + 1)), 300,
                            null);
                    return true;
                }
            });

you can do that on the click of the marker too , but before that you need to do map.setOnMarkerClickListener(mClusterManager);

so that cluster manager gets the click events and you can do

mClusterManagersetOnClusterItemClickListener(new OnClusterItemClickListener<MyItem>() {

}

Bit late to the party

In your onClusterClick function:

LatLngBounds.Builder builder = LatLngBounds.builder();
for (ClusterItem item : cluster.getItems()) {
    builder.include(item.getPosition());
}
final LatLngBounds bounds = builder.build();
getMap().animateCamera(CameraUpdateFactory.newLatLngBounds(bounds, 100));