Opacity fade

package com.mapbox.mapboxandroiddemo.examples.styles;
 
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;
 
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
 
import com.mapbox.mapboxandroiddemo.R;
import com.mapbox.mapboxsdk.Mapbox;
import com.mapbox.mapboxsdk.camera.CameraPosition;
import com.mapbox.mapboxsdk.camera.CameraUpdateFactory;
import com.mapbox.mapboxsdk.maps.MapView;
import com.mapbox.mapboxsdk.maps.MapboxMap;
import com.mapbox.mapboxsdk.maps.OnMapReadyCallback;
import com.mapbox.mapboxsdk.maps.Style;
import com.mapbox.mapboxsdk.style.expressions.Expression;
import com.mapbox.mapboxsdk.style.layers.Layer;
import com.mapbox.mapboxsdk.style.layers.PropertyValue;
import com.mapbox.mapboxsdk.style.layers.RasterLayer;
import com.mapbox.mapboxsdk.style.sources.RasterSource;
 
import static com.mapbox.mapboxsdk.style.expressions.Expression.interpolate;
import static com.mapbox.mapboxsdk.style.expressions.Expression.linear;
import static com.mapbox.mapboxsdk.style.expressions.Expression.stop;
import static com.mapbox.mapboxsdk.style.expressions.Expression.zoom;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.rasterOpacity;
 
/**
* Create an effect of seamlessly fading from one map style to another with runtime styling opacity.
* Go from the Mapbox Streets style to a satellite photo raster layer as the map camera zooms in.
* This is similar to how Snap uses Mapbox for Snap Maps.
*/
public class SatelliteOpacityOnZoomActivity extends AppCompatActivity implements
OnMapReadyCallback {
 
private static final String SATELLITE_RASTER_SOURCE_ID = "SATELLITE_RASTER_SOURCE_ID";
private static final String SATELLITE_RASTER_LAYER_ID = "SATELLITE_RASTER_LAYER_ID";
private MapView mapView;
private MapboxMap mapboxMap;
private boolean satelliteSetToReveal = false;
 
private PropertyValue<Expression> expressionRevealingSatellite = rasterOpacity(interpolate(linear(), zoom(),
stop(15, 0),
stop(18, 1)
));
 
private PropertyValue<Expression> expressionRevealingMapboxStreets = rasterOpacity(interpolate(linear(), zoom(),
stop(12, 1),
stop(16, 0)
));
 
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
 
// Mapbox access token is configured here. This needs to be called either in your application
// object or in the same activity which contains the mapview.
Mapbox.getInstance(this, getString(R.string.access_token));
 
// This contains the MapView in XML and needs to be called after the access token is configured.
setContentView(R.layout.activity_satellite_opacity_on_zoom);
 
mapView = findViewById(R.id.mapView);
mapView.onCreate(savedInstanceState);
mapView.getMapAsync(this);
}
 
@Override
public void onMapReady(@NonNull final MapboxMap mapboxMap) {
mapboxMap.setStyle(Style.MAPBOX_STREETS, new Style.OnStyleLoaded() {
@Override
public void onStyleLoaded(@NonNull Style style) {
 
SatelliteOpacityOnZoomActivity.this.mapboxMap = mapboxMap;
 
// Create a data source for the satellite raster image and add the source to the map
style.addSource(new RasterSource(SATELLITE_RASTER_SOURCE_ID,
"mapbox://mapbox.satellite", 512));
 
// Create a new map layer for the satellite raster images and add the satellite layer to the map.
// Use runtime styling to adjust the satellite layer's opacity based on the map camera's zoom level
style.addLayer(
new RasterLayer(SATELLITE_RASTER_LAYER_ID, SATELLITE_RASTER_SOURCE_ID).withProperties(
expressionRevealingSatellite));
 
// Create a new camera position and animate the map camera to show the fade in/out UI of the satellite layer
mapboxMap.animateCamera(
CameraUpdateFactory.newCameraPosition(new CameraPosition.Builder()
.zoom(19)
.build()), 9000);
 
findViewById(R.id.swap_streets_and_satellite_order_toggle_fab).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
swapStreetsAndSatelliteOrder();
Toast.makeText(SatelliteOpacityOnZoomActivity.this,
R.string.zoom_in_and_out_instruction, Toast.LENGTH_SHORT).show();
}
});
}
});
}
 
private void swapStreetsAndSatelliteOrder() {
mapboxMap.getStyle(new Style.OnStyleLoaded() {
@Override
public void onStyleLoaded(@NonNull Style style) {
Layer satelliteLayer = style.getLayer(SATELLITE_RASTER_LAYER_ID);
if (satelliteLayer != null) {
satelliteLayer.setProperties(
satelliteSetToReveal ? expressionRevealingSatellite : expressionRevealingMapboxStreets
);
}
satelliteSetToReveal = !satelliteSetToReveal;
}
});
}
 
// Add the mapView lifecycle to the activity's lifecycle methods
@Override
public void onResume() {
super.onResume();
mapView.onResume();
}
 
@Override
protected void onStart() {
super.onStart();
mapView.onStart();
}
 
@Override
protected void onStop() {
super.onStop();
mapView.onStop();
}
 
@Override
public void onPause() {
super.onPause();
mapView.onPause();
}
 
@Override
public void onLowMemory() {
super.onLowMemory();
mapView.onLowMemory();
}
 
@Override
protected void onDestroy() {
super.onDestroy();
mapView.onDestroy();
}
 
@Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
mapView.onSaveInstanceState(outState);
}
}