在android中地圖內建立一個圓圈

Question

我想在地圖上建立一個指定半徑的圓圈，就像 RadPad Apple應用程序。

的想法是，圓保持固定的，但是用戶可以移動地圖。 在圓圈內我想計算位於其半徑內的所有標記。

Answer 1

這對我有用。

在XML佈局

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:orientation="vertical" > 
    <fragment 
     android:id="@+id/map" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     class="com.google.android.gms.maps.SupportMapFragment" /> 
</LinearLayout> 

在Main.java

 public class Main extends ActionBarActivity{ 
     private GoogleMap gmap; 
     private LatLng exact_location; 

     protected void onCreate(Bundle savedInstanceState) { 
      super.onCreate(savedInstanceState); 
      setContentView(R.layout.locations_layout); 

      exact_location = new LatLng(LAT,LONG); 
      mapFragment = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map); 
      gmap = mapFragment.getMap(); 
      gmap.moveCamera(CameraUpdateFactory.newLatLngZoom(exact_location,15)); 
      gmap.animateCamera(CameraUpdateFactory.zoomIn()); 

      // Zoom out to zoom level 10, animating with a duration of 2 seconds. 
      gmap.animateCamera(CameraUpdateFactory.zoomTo(10), null); 

      CameraPosition cameraPosition = new CameraPosition.Builder() 
      .target(exact_location)  // Sets the center of the map to Mountain View 
      .zoom(17)     // Sets the zoom 
      .bearing(90)    // Sets the orientation of the camera to east 
      .tilt(85)     // Sets the tilt of the camera to 30 degrees 
      .build();     // Creates a CameraPosition from the builder 

     gmap.animateCamera(CameraUpdateFactory.newCameraPosition(cameraPosition)); 
     CircleOptions circleOptions = new CircleOptions().center(exact_location) 
            .strokeColor(Color.RED) 
            .radius(1000); // In meters 
    gmap.addCircle(circleOptions); 
    }