set Clickable like this.
     MarkerOptions marker=new MarkerOptions().position(resto).title(getAddress(28.6200, 77.2100));
    marker.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_BLUE));
    map.addMarker(marker);
   map.setOnMarkerClickListener(new GoogleMap.OnMarkerClickListener() {
        @Override
        public boolean onMarkerClick(Marker marker) {
            if(marker.getTitle().equals(getAddress(28.6200, 77.2100))){
                Log.e("Delhi","Delhi");
                Log.e("Destance",""+distance(resto.latitude,resto.longitude,Delhi1.latitude,Delhi1.longitude,"M"));
            }else if(marker.getTitle().equals("Marker in Delhi1")){
                Log.e("Delhi1","Delhi1");
            }
                return false;
        }
    });
GetAddress metgod()
   public String getAddress(double lat, double lng) {
    Geocoder geocoder = new Geocoder(MapsActivity.this, Locale.getDefault());
    String Address=" ";
    Log.e("ADDRESS","ADDRESS");
    try {
        List<Address> addresses = geocoder.getFromLocation(lat, lng, 1);
        Address obj = addresses.get(0);
        String add = obj.getAddressLine(0);
        Address= obj.getAddressLine(0);
        add = add + "\n" + obj.getCountryName();
        add = add + "\n" + obj.getCountryCode();
        add = add + "\n" + obj.getAdminArea();
        add = add + "\n" + obj.getPostalCode();
        add = add + "\n" + obj.getSubAdminArea();
        add = add + "\n" + obj.getLocality();
        add = add + "\n" + obj.getSubThoroughfare();
        Log.e("IGA", "Address" + add);
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
        Toast.makeText(this, e.getMessage(), Toast.LENGTH_SHORT).show();
    }
    return Address;
}