Examples

Style lines using an identity property function

package com.mapbox.mapboxandroiddemo.examples.dds;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import com.mapbox.mapboxandroiddemo.R;
import com.mapbox.mapboxsdk.Mapbox;
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.layers.LineLayer;
import com.mapbox.mapboxsdk.style.layers.Property;
import com.mapbox.mapboxsdk.style.layers.PropertyFactory;
import com.mapbox.mapboxsdk.style.sources.GeoJsonSource;
import java.io.InputStream;
import timber.log.Timber;
import static com.mapbox.mapboxsdk.style.expressions.Expression.get;
import static com.mapbox.mapboxsdk.style.expressions.Expression.match;
import static com.mapbox.mapboxsdk.style.expressions.Expression.rgb;
import static com.mapbox.mapboxsdk.style.expressions.Expression.stop;
/**
* Use data-driven styling to set a line's color based on imported GeoJSON.
*/
public class StyleLineIdentityPropertyActivity extends AppCompatActivity {
private MapView mapView;
@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_style_line);
mapView = findViewById(R.id.mapView);
mapView.onCreate(savedInstanceState);
mapView.getMapAsync(new OnMapReadyCallback() {
@Override
public void onMapReady(@NonNull final MapboxMap mapboxMap) {
mapboxMap.setStyle(Style.MAPBOX_STREETS, new Style.OnStyleLoaded() {
@Override
public void onStyleLoaded(@NonNull Style style) {
// Retrieve GeoJSON from local file and add it to the map
style.addSource(new GeoJsonSource("lines",
loadGeoJsonFromAsset("golden_gate_lines.geojson")));
// Create a LineLayer. Use lineColor and stops to draw red and blue lines on the map
style.addLayer(new LineLayer("finalLines", "lines").withProperties(
PropertyFactory.lineColor(
match(get("color"), rgb(0, 0, 0),
stop("red", rgb(247, 69, 93)),
stop("blue", rgb(51, 201, 235)))),
PropertyFactory.visibility(Property.VISIBLE),
PropertyFactory.lineWidth(3f)
));
}
});
}
});
}
@Override
protected void onStart() {
super.onStart();
mapView.onStart();
}
@Override
public void onResume() {
super.onResume();
mapView.onResume();
}
@Override
public void onPause() {
super.onPause();
mapView.onPause();
}
@Override
protected void onStop() {
super.onStop();
mapView.onStop();
}
@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);
}
private String loadGeoJsonFromAsset(String filename) {
try {
// Load GeoJSON file
InputStream is = getAssets().open(filename);
int size = is.available();
byte[] buffer = new byte[size];
is.read(buffer);
is.close();
return new String(buffer, "UTF-8");
} catch (Exception exception) {
Timber.e("Exception Loading GeoJSON: %s", exception.toString());
exception.printStackTrace();
return null;
}
}
}