add collection and style smooth reload example

MapboxGLAndroidSDKTestApp/src/main/AndroidManifest.xml

@@ -484,6 +484,17 @@
                 android:name="android.support.PARENT_ACTIVITY"
                 android:value=".activity.FeatureOverviewActivity" />
         </activity>
+        <activity
+            android:name=".activity.style.CollectionUpdateOnStyleChange"
+            android:description="@string/description_collection_style_change"
+            android:label="@string/activity_collection_style_change">
+            <meta-data
+                android:name="@string/category"
+                android:value="@string/category_style" />
+            <meta-data
+                android:name="android.support.PARENT_ACTIVITY"
+                android:value=".activity.FeatureOverviewActivity" />
+        </activity>
         <activity
             android:name=".activity.style.FillExtrusionActivity"
             android:description="@string/description_fill_extrusion_layer"

MapboxGLAndroidSDKTestApp/src/main/java/com/mapbox/mapboxsdk/testapp/activity/style/CollectionUpdateOnStyleChange.kt

@@ -0,0 +1,135 @@
+package com.mapbox.mapboxsdk.testapp.activity.style
+
+import android.graphics.Color
+import android.os.Bundle
+import android.support.design.widget.FloatingActionButton
+import android.support.v7.app.AppCompatActivity
+import android.widget.Toast
+import com.mapbox.geojson.Feature
+import com.mapbox.geojson.FeatureCollection
+import com.mapbox.geojson.LineString
+import com.mapbox.geojson.Point
+import com.mapbox.mapboxsdk.geometry.LatLng
+import com.mapbox.mapboxsdk.geometry.LatLngBounds
+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.PropertyFactory
+import com.mapbox.mapboxsdk.style.sources.GeoJsonSource
+import com.mapbox.mapboxsdk.testapp.R
+import java.util.*
+import kotlinx.android.synthetic.main.activity_collection_update_on_style_change.*
+
+/**
+ * Test activity that verifies whether the GeoJsonSource transition over style changes can be smooth.
+ */
+class CollectionUpdateOnStyleChange : AppCompatActivity(), OnMapReadyCallback, Style.OnStyleLoaded {
+
+  private lateinit var mapboxMap: MapboxMap
+  private var currentStyleIndex: Int = 0
+
+  override fun onCreate(savedInstanceState: Bundle?) {
+    super.onCreate(savedInstanceState)
+    setContentView(R.layout.activity_collection_update_on_style_change)
+    mapView.onCreate(savedInstanceState)
+    mapView.getMapAsync(this)
+    setupStyleChangeView()
+    Toast.makeText(
+      this,
+      "Make sure that the collection doesn't blink on style change",
+      Toast.LENGTH_LONG)
+      .show()
+  }
+
+  override fun onMapReady(map: MapboxMap) {
+    mapboxMap = map
+    mapboxMap.setStyle(Style.Builder().fromUri(STYLES[currentStyleIndex]), this)
+  }
+
+  override fun onStyleLoaded(style: Style) {
+    setupLayer(style)
+  }
+
+  private fun setupLayer(style: Style) {
+    val source = GeoJsonSource("source", featureCollection)
+    val lineLayer = LineLayer("layer", "source")
+      .withProperties(
+        PropertyFactory.lineColor(Color.RED),
+        PropertyFactory.lineWidth(10f)
+      )
+
+    style.addSource(source)
+    style.addLayer(lineLayer)
+  }
+
+  private fun setupStyleChangeView() {
+    val fabStyles = findViewById<FloatingActionButton>(R.id.fabStyles)
+    fabStyles.setOnClickListener {
+      currentStyleIndex++
+      if (currentStyleIndex == STYLES.size) {
+        currentStyleIndex = 0
+      }
+      mapboxMap.setStyle(Style.Builder().fromUri(STYLES[currentStyleIndex]), this)
+    }
+  }
+
+  override fun onStart() {
+    super.onStart()
+    mapView.onStart()
+  }
+
+  override fun onResume() {
+    super.onResume()
+    mapView.onResume()
+  }
+
+  override fun onPause() {
+    super.onPause()
+    mapView.onPause()
+  }
+
+  override fun onStop() {
+    super.onStop()
+    mapView.onStop()
+  }
+
+  override fun onSaveInstanceState(outState: Bundle) {
+    super.onSaveInstanceState(outState)
+    mapView.onSaveInstanceState(outState)
+  }
+
+  override fun onDestroy() {
+    super.onDestroy()
+    mapView.onDestroy()
+  }
+
+  override fun onLowMemory() {
+    super.onLowMemory()
+    mapView.onLowMemory()
+  }
+
+  companion object {
+
+    private val STYLES = arrayOf(Style.MAPBOX_STREETS, Style.OUTDOORS, Style.LIGHT, Style.DARK, Style.SATELLITE, Style.SATELLITE_STREETS, Style.TRAFFIC_DAY, Style.TRAFFIC_NIGHT)
+
+    private val featureCollection: FeatureCollection
+
+    init {
+      val bounds = LatLngBounds.from(60.0, 100.0, -60.0, -100.0)
+      val points = ArrayList<Point>()
+      for (i in 0 until 1000) {
+        val latLng = getLatLngInBounds(bounds)
+        points.add(Point.fromLngLat(latLng.longitude, latLng.latitude))
+      }
+      featureCollection = FeatureCollection.fromFeature(Feature.fromGeometry(LineString.fromLngLats(points)))
+    }
+
+    private fun getLatLngInBounds(bounds: LatLngBounds): LatLng {
+      val generator = Random()
+      val randomLat = bounds.latSouth + generator.nextDouble() * (bounds.latNorth - bounds.latSouth)
+      val randomLon = bounds.lonWest + generator.nextDouble() * (bounds.lonEast - bounds.lonWest)
+      return LatLng(randomLat, randomLon)
+    }
+  }
+}

MapboxGLAndroidSDKTestApp/src/main/res/layout/activity_collection_update_on_style_change.xml

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="utf-8"?>
+<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:id="@+id/coordinator_layout"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical">
+
+    <com.mapbox.mapboxsdk.maps.MapView
+        android:id="@id/mapView"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent" />
+
+    <android.support.design.widget.FloatingActionButton
+        android:id="@id/fabStyles"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_gravity="end|bottom"
+        android:layout_margin="@dimen/fab_margin"
+        android:src="@drawable/ic_layers"
+        app:backgroundTint="@color/primary"
+        app:layout_anchorGravity="bottom|end" />
+
+</android.support.design.widget.CoordinatorLayout>

MapboxGLAndroidSDKTestApp/src/main/res/values/descriptions.xml

@@ -50,6 +50,7 @@
     <string name="description_style_file">Use a local file as the style</string>
     <string name="description_map_in_dialog">Display a map inside a dialog fragment</string>
     <string name="description_circle_layer">Show bus stops and route in Singapore</string>
+    <string name="description_collection_style_change">Verify that updating the GeoJsonSource across style changes allows for smooth transitions</string>
     <string name="description_url_transform">Transform urls on the fly</string>
     <string name="description_cache_management">Control the cache management with FileSource API</string>
     <string name="description_restricted_bounds">Limit viewport to Iceland</string>

MapboxGLAndroidSDKTestApp/src/main/res/values/titles.xml

@@ -34,6 +34,7 @@
     <string name="activity_gradient_line">Gradient line layer</string>
     <string name="activity_data_driven_style">Data Driven Style</string>
     <string name="activity_circle_layer">Circle layer</string>
+    <string name="activity_collection_style_change">Collection updates on style changes</string>
     <string name="activity_style_file">Local Style file</string>
     <string name="activity_geojson_clustering">GeoJson Clustering</string>
     <string name="activity_geojson_realtime">Add live realtime data</string>