Offline sample

content_main.xml

<?xml version="1.0" encoding="utf-8"?>
<com.mapbox.mapboxsdk.maps.MapView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/mapview"
    android:layout_width="match_parent"
    app:center_latitude="65.970773"
    app:center_longitude="-18.532800"
    app:zoom="16"
    android:layout_height="match_parent" />

MainActivity.java

public class MainActivity extends AppCompatActivity {

    private MapView mMapView;
    private OfflineManager mOfflineManager;
    private OfflineRegion mOfflineRegion;
    private MapboxMap mapboxMap;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.content_main);

        mMapView = (MapView) findViewById(R.id.mapview);
        mMapView.setAccessToken("pk.eyJ1IjoidG9icnVuIiwiYSI6ImNpajVlajR0cjAwNjN2NmtyY204eWw2eG0ifQ.x3_WEoExNW5Qyv9T3Vj7Mw");
        mMapView.setStyleUrl(Style.DARK);
        mMapView.onCreate(savedInstanceState);

        mMapView.getMapAsync(new OnMapReadyCallback() {
            @Override
            public void onMapReady(MapboxMap map) {
                mapboxMap = map;
                Toast.makeText(MainActivity.this, "OnMapReady", Toast.LENGTH_LONG).show();
                mOfflineManager = OfflineManager.getInstance(MainActivity.this);
                mOfflineManager.setAccessToken("pk.eyJ1IjoidG9icnVuIiwiYSI6ImNpajVlajR0cjAwNjN2NmtyY204eWw2eG0ifQ.x3_WEoExNW5Qyv9T3Vj7Mw");
                mOfflineManager.listOfflineRegions(new OfflineManager.ListOfflineRegionsCallback() {
                    @Override
                    public void onList(OfflineRegion[] offlineRegions) {
                        // Check result
                        if (offlineRegions == null || offlineRegions.length == 0) {
                            Log.e("TAG", "YOU HAVE NO REGIONS, START DOWNLOAD");
                            downloadRegion();
                            return;
                        }

                        Log.v("TAG", "WE HAVE A REGION!");
                    }

                    @Override
                    public void onError(String error) {
                        Log.e("TAG", "Error: " + error);
                    }
                });
            }
        });
    }

    private void downloadRegion() {
        Projection projection = mapboxMap.getProjection();
        LatLng topLeft = projection.fromScreenLocation(new PointF(0, 0));
        LatLng bottomRight = projection.fromScreenLocation(
                new PointF(mMapView.getWidth(), mMapView.getHeight()));

        LatLngBounds bounds = new LatLngBounds.Builder()
                .include(topLeft)
                .include(bottomRight)
                .build();

        Log.v("TAG", topLeft + " " + bottomRight);

        Log.v("TAG", bounds.toString());

        mOfflineManager.createOfflineRegion(new OfflineTilePyramidRegionDefinition(
                Style.MAPBOX_STREETS,
                bounds,
                mapboxMap.getCameraPosition().zoom,
                mapboxMap.getMaxZoom(),
                1.0f
        ), new byte[0], new OfflineManager.CreateOfflineRegionCallback() {
            @Override
            public void onCreate(OfflineRegion offlineRegion) {
                offlineRegion.setDownloadState(OfflineRegion.STATE_ACTIVE);
                offlineRegion.setObserver(new OfflineRegion.OfflineRegionObserver() {
                    @Override
                    public void onStatusChanged(OfflineRegionStatus status) {
                        if (status.isComplete()) {
                            Toast.makeText(MainActivity.this, "Done saving map.", Toast.LENGTH_SHORT).show();
                        }
                        Log.d("TAG", "completed resource size " + status.getCompletedResourceSize());
                    }

                    @Override
                    public void onError(OfflineRegionError error) {
                        Log.e("TAG", "ERROR " + error);
                    }

                    @Override
                    public void mapboxTileCountLimitExceeded(long limit) {
                        Log.e("TAG", "LIMIT REACHED " + limit);
                    }
                });
            }

            @Override
            public void onError(String error) {
                Log.e("TAG", "ERROR " + error);
            }
        });
    }


    @Override
    protected void onResume() {
        super.onResume();
        mMapView.onResume();
    }

    @Override
    protected void onPause() {
        super.onPause();
        mMapView.onResume();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        mMapView.onDestroy();
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        mMapView.onSaveInstanceState(outState);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

}