MapView Polygon

This example shows how to add Polygons in MapView

Add Polygon from a set of Latlng
Query Visible Polygon in Rect
Set Polygon stroke
Set Polygon color

For all code examples, refer to Android Maps SDK Code Examples

activity_polygon.xml view source

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<?xml version="1.0" encoding="utf-8"?>
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<androidx.coordinatorlayout.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
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    xmlns:app="http://schemas.android.com/apk/res-auto"
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    xmlns:tools="http://schemas.android.com/tools"
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    android:layout_width="match_parent"
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    android:layout_height="match_parent"
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    tools:context=".PolygonActivity">
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    <ai.nextbillion.maps.core.MapView
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        android:id="@+id/map_view"
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        android:layout_width="match_parent"
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        android:layout_height="match_parent"
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        app:nbmap_cameraTargetLat="53.5493093866953"
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        app:nbmap_cameraTargetLng="10.031835837897463"
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        app:nbmap_cameraZoom="10"
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        app:nbmap_uiAttribution="false" />
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    <androidx.core.widget.NestedScrollView
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        android:id="@+id/bottomSheet"
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        android:layout_width="match_parent"
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        android:layout_height="wrap_content"
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        android:background="@color/white"
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        app:behavior_hideable="true"
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        app:layout_behavior="com.google.android.material.bottomsheet.BottomSheetBehavior">
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        <LinearLayout
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            android:layout_width="match_parent"
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            android:layout_height="wrap_content"
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            android:orientation="vertical">
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            <TextView
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                android:layout_width="68dp"
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                android:layout_height="1dp"
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                android:layout_gravity="center_horizontal"
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                android:layout_marginTop="13dp"
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                android:background="@drawable/nbmap_radius_10_grey_bg" />
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            <TextView
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                android:layout_width="wrap_content"
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                android:layout_height="wrap_content"
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                android:layout_marginTop="13dp"
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                android:paddingHorizontal="16dp"
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                android:text="@string/polygonSetting"
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                android:textColor="@color/black"
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                android:textSize="24sp" />
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            <ai.nextbillion.view.SettingSwitchView
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                android:id="@+id/pointEnable"
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                android:layout_width="match_parent"
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                android:layout_height="wrap_content"
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                android:layout_marginLeft="16dp"
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                android:layout_marginRight="16dp" />
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            <ai.nextbillion.view.ColorSelectorView
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                android:id="@+id/polygon_color"
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                android:layout_width="match_parent"
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                android:layout_height="wrap_content"
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                android:layout_marginTop="10dp" />
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            <ai.nextbillion.view.ColorSelectorView
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                android:id="@+id/polygon_stroke_Color"
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                android:layout_width="match_parent"
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                android:layout_height="wrap_content"
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                android:layout_marginTop="10dp" />
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            <ai.nextbillion.view.SliderBarView
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                android:id="@+id/lineWidth"
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                android:layout_width="match_parent"
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                android:layout_height="wrap_content"
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                android:layout_marginBottom="10dp" />
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        </LinearLayout>
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    </androidx.core.widget.NestedScrollView>
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    <com.google.android.material.floatingactionbutton.FloatingActionButton
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        android:id="@+id/fb_clean"
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        android:layout_width="wrap_content"
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        android:layout_height="wrap_content"
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        android:layout_gravity="right"
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        android:layout_marginTop="120dp"
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        android:layout_marginRight="16dp"
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        android:backgroundTint="@color/purple_200"
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        android:src="@android:drawable/ic_menu_close_clear_cancel"
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        android:tooltipText="Clean"
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        app:fabSize="mini" />
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    <TextView
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        android:id="@+id/fb_check"
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        android:layout_width="40dp"
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        android:layout_height="40dp"
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        android:layout_gravity="right"
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        android:layout_marginTop="170dp"
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        android:layout_marginRight="16dp"
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        android:background="@drawable/shape_circle_40_md_grey_400"
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        android:gravity="center"
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        android:text="@string/polygonStrokeCheck" />
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    <com.google.android.material.floatingactionbutton.FloatingActionButton
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        android:id="@+id/fb_expand"
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        android:layout_width="wrap_content"
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        android:layout_height="wrap_content"
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        android:layout_gravity="right|bottom"
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        android:layout_marginRight="16dp"
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        android:layout_marginBottom="56dp"
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        android:backgroundTint="@color/purple_200"
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        android:src="@android:drawable/ic_dialog_info"
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        android:tooltipText="Create"
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        android:visibility="gone"
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        app:fabSize="mini" />
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    <ImageView
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        android:id="@+id/iv_back"
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        android:layout_width="40dp"
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        android:layout_height="40dp"
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        android:layout_gravity="top|left"
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        android:layout_marginLeft="16dp"
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        android:layout_marginTop="16dp"
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        android:background="@drawable/circle_white_bg"
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        android:src="@drawable/icon_back"
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        app:tint="@color/color_back_icon" />
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</androidx.coordinatorlayout.widget.CoordinatorLayout>

PolygonActivity view source

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public class PolygonActivity extends AppCompatActivity implements View.OnClickListener {
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   private NextbillionMap mMap;
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   private MapView mapView;
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   private BottomSheetBehavior bottomSheetBehavior;
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   private Polygon polygon;
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   // for stroke
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   private Polyline polyline;
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   // polygon
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   private List<LatLng> polygonPoints = new ArrayList<>();
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   private List<Marker> polygonMarkers = new ArrayList<>();
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   private LatLngBounds latLngBounds;
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   private Marker clickMarker;
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   // menu
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   private ColorSelectorView polygonColorSelectorView;
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   private ColorSelectorView polygonStrokeColorSelectorView;
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   private SliderBarView polygonStrokeWidthSliderBarView;
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   private SettingSwitchView pointSettingSwitchView;
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   private FloatingActionButton fbInfoFloatingActionButton;
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   private TextView fbNoticeButton;
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   private String polygonColor = "#1E58A5";
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   private String polygonStrokeColor = "#FF0000";
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   private float stockWidth = 2;
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   private int polygonIndex = 1;
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   private boolean showPolygonVertex = true;
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   @Override
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   protected void onCreate(Bundle savedInstanceState) {
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       super.onCreate(savedInstanceState);
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       setContentView(R.layout.activity_polygon);
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       mapView = findViewById(R.id.map_view);
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       mapView.onCreate(savedInstanceState);
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       mapView.getMapAsync(this::onMapSync);
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       // button
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       findViewById(R.id.fb_clean).setOnClickListener(this);
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       fbInfoFloatingActionButton = findViewById(R.id.fb_expand);
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       fbInfoFloatingActionButton.setOnClickListener(this);
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       fbNoticeButton = findViewById(R.id.fb_check);
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       fbNoticeButton.setOnClickListener(this);
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       // menu
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       polygonColorSelectorView = findViewById(R.id.polygon_color);
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       polygonStrokeColorSelectorView = findViewById(R.id.polygon_stroke_Color);
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       polygonStrokeWidthSliderBarView = findViewById(R.id.lineWidth);
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       pointSettingSwitchView = findViewById(R.id.pointEnable);
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       findViewById(R.id.iv_back).setOnClickListener(this);
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       initData();
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       initBottomSheet();
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   }
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   private void initData() {
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       polygonColorSelectorView.setTitle(getResources().getString(R.string.polygonColor));
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       polygonColorSelectorView.initColor(polygonColor);
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       polygonStrokeColorSelectorView.setTitle(getResources().getString(R.string.polygonStrokeColor));
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       polygonStrokeColorSelectorView.initColor(polygonStrokeColor);
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       polygonStrokeWidthSliderBarView.setTitle(getResources().getString(R.string.polygonStrokeWidth));
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       polygonStrokeWidthSliderBarView.initSeekBar(2, 0, 20, "px", 1);
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       pointSettingSwitchView.setTitle(getResources().getString(R.string.polygon_point_show));
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       pointSettingSwitchView.defaultValue(true);
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       polygonColorSelectorView.setOnColorChangedListener(new ColorSelectorView.OnColorChangedListener() {
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           @Override
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           public void onColorChanged(@NonNull String color) {
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               polygonColor = color;
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               if (polygon != null) {
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                   polygon.setFillColor(Color.parseColor(color));
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               }
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           }
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       });
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       polygonStrokeColorSelectorView.setOnColorChangedListener(new ColorSelectorView.OnColorChangedListener() {
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           @Override
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           public void onColorChanged(@NonNull String color) {
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               polygonStrokeColor = color;
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               int colorHex = Color.parseColor(color);
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               if (polyline != null) {
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                   polyline.setColor(colorHex);
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               }
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           }
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       });
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       polygonStrokeWidthSliderBarView.setOnSliderChangedListener(new SliderBarView.OnSliderChangedListener() {
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           @Override
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           public void onSliderChanged(float value) {
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               stockWidth = value;
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               if (polyline != null) {
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                   polyline.setWidth(value);
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               }
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           }
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       });
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       pointSettingSwitchView.setOnSwitchChangedLister(new SettingSwitchView.OnSwitchChangedLister() {
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           @Override
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           public void onSwitchChanged(boolean status) {
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               showPolygonVertex = status;
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               upDataMarkerBySwitchState();
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           }
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       });
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   }
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   private void upDataMarkerBySwitchState() {
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       if (polygonMarkers == null || polygonMarkers.isEmpty()) {
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           return;
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       }
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       for (Marker marker : polygonMarkers) {
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           marker.setIcon(IconFactory.getInstance(PolygonActivity.this)
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                   .fromResource((showPolygonVertex || polygonPoints.size() < 3) ? R.mipmap.ic_blue_dot : R.mipmap.ic_marker_transparent));
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       }
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   }
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   private void onMapSync(NextbillionMap map) {
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       mMap = map;
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       addMapListener();
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       mMap.setStyle( Style.Builder().fromUri(StyleConstants.LIGHT))      
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   }
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   private void addMapListener() {
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       mMap.addOnMapLongClickListener(new NextbillionMap.OnMapLongClickListener() {
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           @Override
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           public boolean onMapLongClick(@NonNull LatLng latLng) {
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               polygonPoints.add(latLng);
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               MarkerOptions markerOptions = new MarkerOptions()
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                       .setTitle(String.valueOf(polygonIndex))
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                       .position(latLng)
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                       .setIcon(IconFactory.getInstance(PolygonActivity.this)
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                               .fromResource((showPolygonVertex || polygonPoints.size() < 3) ? R.mipmap.ic_blue_dot : R.mipmap.ic_marker_transparent));
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               polygonMarkers.add(mMap.addMarker(markerOptions));
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               polygonIndex ++;
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               if (polygonPoints.size() > 2) {
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                   createPolygon();
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               }
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               return false;
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           }
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       });
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       mMap.addOnMapClickListener(new NextbillionMap.OnMapClickListener() {
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           @Override
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           public boolean onMapClick(@NonNull LatLng latLng) {
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               if (clickMarker != null) {
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                   mMap.removeMarker(clickMarker);
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               }
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               clickMarker = mMap.addMarker(latLng);
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               Point clickPoint = new Point(latLng.getLongitude(),latLng.getLatitude());
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               List<Point> polygonLngLatPoints = new ArrayList<>();
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               for (LatLng point : polygonPoints) {
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                   polygonLngLatPoints.add(new Point(point.getLongitude(),point.getLatitude()));
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               }
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               boolean isPointInPolygon = PolygonUtils.isPointInPolygon(clickPoint,PolygonUtils.getPolygon(true,polygonLngLatPoints));
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               if (isPointInPolygon) {
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                   Toast.makeText(PolygonActivity.this, "this point is in polygon", Toast.LENGTH_SHORT).show();
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               }
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               return false;
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           }
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       });
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       mMap.addOnMoveListener(new NextbillionMap.OnMoveListener() {
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           @Override
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           public void onMoveBegin(@NonNull MoveGestureDetector moveGestureDetector) {
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           }
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           @Override
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           public void onMove(@NonNull MoveGestureDetector moveGestureDetector) {
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           }
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           @Override
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           public void onMoveEnd(@NonNull MoveGestureDetector moveGestureDetector) {
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               boolean isPolygonInScreen = checkPolygonVisibility();
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               if (isPolygonInScreen) {
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                   fbNoticeButton.setBackgroundResource(R.drawable.shape_circle_40_purple_200);
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               } else {
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                   fbNoticeButton.setBackgroundResource(R.drawable.shape_circle_40_md_grey_400);
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               }
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           }
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       });
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       mMap.setOnMarkerClickListener(new NextbillionMap.OnMarkerClickListener() {
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           @Override
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           public boolean onMarkerClick(@NonNull Marker marker) {
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               if (marker == clickMarker) {
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                   mMap.removeMarker(clickMarker);
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                   clickMarker = null;
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               }
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               return false;
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           }
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       });
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   }
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   private boolean checkPolygonVisibility() {
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       if (mMap == null || mMap.getProjection() == null || latLngBounds == null) {
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           return false;
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       }
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       LatLngBounds isInScreen = mMap.getProjection().getVisibleRegion().latLngBounds.intersect(latLngBounds);
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       return isInScreen != null;
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   }
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   private void cleanPolygon() {
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       if (mMap == null || polygon == null) {
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           Toast.makeText(PolygonActivity.this, "No polygon need remove", Toast.LENGTH_SHORT).show();
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           return;
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       }
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       mMap.removePolygon(polygon);
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       polygon = null;
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       polygonPoints.clear();
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       latLngBounds = null;
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       // polygon marker
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       for (Marker marker : polygonMarkers) {
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           mMap.removeMarker(marker);
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       }
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       polygonMarkers.clear();
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       // line
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       if (polyline != null) {
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           mMap.removePolyline(polyline);
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           polyline = null;
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       }
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   }
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   private void createPolygon() {
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       // check map
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       if (mMap == null) {
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           Toast.makeText(this, getResources().getString(R.string.waite_notice), Toast.LENGTH_SHORT).show();
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           return;
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       }
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       // check data
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       if (polygonPoints.isEmpty()) {
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           Toast.makeText(this, getResources().getString(R.string.polygon_empty_point_notice), Toast.LENGTH_SHORT).show();
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           return;
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       }
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       if (polyline != null) {
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           mMap.removePolyline(polyline);
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       }
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       if (polygon != null) {
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           mMap.removePolygon(polygon);
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       }
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       // update marker show style
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       upDataMarkerBySwitchState();
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       // add polygon
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       latLngBounds = new LatLngBounds.Builder().includes(polygonPoints).build();
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       PolygonOptions polygonOptions = new PolygonOptions();
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       polygonOptions.addAll(polygonPoints)
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               .fillColor(Color.parseColor(polygonColor))
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               .strokeColor(Color.parseColor(polygonStrokeColor));
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       polygon = mMap.addPolygon(polygonOptions);
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       // add polygon stroke by polyline
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       List<LatLng> polylinePoints = new ArrayList<>(polygonPoints);
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       polylinePoints.add(polygonPoints.get(0));
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       polylinePoints.add(polygonPoints.get(1));
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       PolylineOptions polylineOptions = new PolylineOptions()
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               .addAll(polylinePoints)
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               .color(Color.parseColor(polygonStrokeColor))
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               .width(stockWidth);
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       polyline = mMap.addPolyline(polylineOptions);
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       // change check button color
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       fbNoticeButton.setBackgroundResource(R.drawable.shape_circle_40_purple_200);
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   }
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   private void initBottomSheet() {
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       bottomSheetBehavior = BottomSheetBehavior.from(findViewById(R.id.bottomSheet));
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       bottomSheetBehavior.setState(BottomSheetBehavior.STATE_EXPANDED);
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       bottomSheetBehavior.setPeekHeight((int) Utils.dpToPx(60));
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       bottomSheetBehavior.addBottomSheetCallback(new BottomSheetBehavior.BottomSheetCallback() {
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           @Override
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           public void onStateChanged(@NonNull View bottomSheet, int newState) {
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               if (newState == BottomSheetBehavior.STATE_HIDDEN) {
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                   fbInfoFloatingActionButton.setVisibility(View.VISIBLE);
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               } else {
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                   fbInfoFloatingActionButton.setVisibility(View.GONE);
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               }
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           }
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           @Override
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           public void onSlide(@NonNull View bottomSheet, float slideOffset) {
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           }
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       });
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   }
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   ///////////////////////////////////////////////////////////////////////////
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   // Lifecycle
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   ///////////////////////////////////////////////////////////////////////////
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   @Override
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   protected void onStart() {
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       super.onStart();
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       mapView.onStart();
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   }
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   @Override
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   protected void onResume() {
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       super.onResume();
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       mapView.onResume();
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   }
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   @Override
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   protected void onPause() {
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       super.onPause();
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       mapView.onPause();
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   }
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   @Override
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   protected void onStop() {
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       super.onStop();
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       mapView.onStop();
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   }
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   @Override
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   protected void onSaveInstanceState(@NonNull Bundle outState) {
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       super.onSaveInstanceState(outState);
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       mapView.onSaveInstanceState(outState);
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   }
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   @Override
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   protected void onDestroy() {
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       super.onDestroy();
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       mapView.onDestroy();
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   }
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   @Override
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   public void onLowMemory() {
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       super.onLowMemory();
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       mapView.onLowMemory();
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   }
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   @Override
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   public void onClick(View v) {
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       if (v.getId() == R.id.fb_clean) {
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           cleanPolygon();
330
       } else if (v.getId() == R.id.fb_expand) {
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           bottomSheetBehavior.setState(BottomSheetBehavior.STATE_EXPANDED);
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       } else if (v.getId() == R.id.fb_check) {
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           boolean isPolygonInScreen = checkPolygonVisibility();
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           String message = getResources().getString(R.string.polygin_visibility_notice);
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           if (!isPolygonInScreen) {
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               message = getResources().getString(R.string.polygon_invisibility_notice);
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           }
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           Toast.makeText(PolygonActivity.this, message, Toast.LENGTH_SHORT).show();
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       } else if (v.getId() == R.id.iv_back) {
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           finish();
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       }
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   }
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}

initData

Initialises the data for the polygon activity.
Sets up various UI components such as color selectors, slider bars, and switch views. It also defines listeners for these components to handle user interactions and update the corresponding data values.

addMapListener

Adds listeners to the map.
Sets up event listeners for various map interactions such as long clicks, clicks, moves, and marker clicks. These listeners perform actions such as adding markers, creating polygons, checking polygon visibility, and removing markers and polygons.

checkPolygonVisibility

Checks if the polygon is currently visible on the map. It relies on the map's projection and the bounds of the polygon to determine if the polygon is within the visible region of the map. It returns a boolean value indicating the visibility status of the polygon.

createPolygon

Creates a polygon on the map. It checks if the necessary data, such as the map and polygon points, are available. It removes any existing polyline and polygon from the map. It updates the marker show style based on the switch state. Then it adds a polygon and a polyline to the map using the provided polygon points, colors, and stroke width.

cleanPolygon

Removes the polygon and related markers from the map. It checks if the map and polygon are available and removes them from the map. It also clears the polygon points, marker list, and polyline if they exist.

These methods are part of the PolygonActivity class and are used to initialize and manage the polygon functionality in the corresponding Android activity.

The code also includes various lifecycle methods (onStart, onResume, onPause, onStop, onSaveInstanceState, onDestroy, onLowMemory) that should be implemented when using the MapView to properly manage its lifecycle and handle configuration changes.

Note: The code uses the Nextbillion Maps SDK, which provides map-related functionalities. It also utilizes the LatLng class to represent geography.