android-studio - 如何在谷歌地图中使用标记和折线的中点绘制多边形

Question

我想在 map 上绘制一个手绘多边形。我从简单的谷歌地图开始并绘制多边形并且它工作正常但现在我正在寻找用户如何通过单击 map 上的点和拉伸(stretch)标记中间点来绘制多边形多边形。

现在我的多边形 map 看起来像:



我想实现:



这是我的代码:

     public class MapActivity extends FragmentActivity implements OnMapReadyCallback {

private GoogleMap mMap;
Button save_field;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_map);

    // Retrieve the content view that renders the map.
    SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
            .findFragmentById(R.id.map);
    mapFragment.getMapAsync(this);

    FrameLayout Frame_map = (FrameLayout) findViewById(R.id.frame_map);
    Button btn_draw_State = (Button) findViewById(R.id.btn_draw_State);
    final Boolean[] Is_MAP_Moveable = {false}; // to detect map is movable

    // Button will change Map movable state
    btn_draw_State.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Is_MAP_Moveable[0] = !Is_MAP_Moveable[0];
        }
    });
}

public GoogleMap getmMap() {
    return mMap;
}

@Override
public void onMapReady(GoogleMap googleMap) {
    mMap = googleMap;

    /*polygon should be declared as member of the fragment class if you want just one polygon at a time*/
    final List<LatLng> latLngList = new ArrayList<>(); // list of polygons
    final List<Marker> markerList = new ArrayList<>();

    mMap.setOnMapClickListener(new GoogleMap.OnMapClickListener() {
        @Override
        public void onMapClick(final LatLng latLng) {


            MarkerOptions markerOptions = new MarkerOptions(); //create marker options
            markerOptions.position(latLng);
            markerOptions.title(latLng.latitude + ":" + latLng.longitude);
            mMap.clear();
            mMap.setMapType(GoogleMap.MAP_TYPE_SATELLITE);
            mMap.animateCamera(CameraUpdateFactory.newLatLng(latLng));
            Marker marker = mMap.addMarker(markerOptions);
            latLngList.add(latLng);
            markerList.add(marker);


            Polygon polygon = null;
            if (polygon != null ) polygon.remove(); // remove the previously drawn polygon
            PolygonOptions polygonOptions = new PolygonOptions().addAll(latLngList).clickable(true);
            polygon = mMap.addPolygon(new PolygonOptions().addAll(latLngList).fillColor(Color.BLUE).strokeColor(Color.RED));//add new polygon

        }
    });
             save_field = findViewById(R.id.save);
             save_field.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {

            startActivity(new Intent(MapActivity.this, Save_Fields.class));
            finish();
        }
    });
  }
 }

我在这个主题上做了很多研究和开发，但没有得到一个完美的方法来在谷歌地图中实现这样的事情。如果有人知道这种方法，那么请帮我找出解决方案。先感谢您:)

Answer 1

使用 MapDrawingTools 库在谷歌地图中绘制多边形、折线和点，并将坐标返回到您的应用程序。该库对于选择多个点或绘制土地边界以从用户那里获取数据的应用程序很有用。

使用指南

在您的应用中添加以下代码:

DrawingOption.DrawingType currentDrawingType = DrawingOption.DrawingType.POLYGON;
Intent intent =
new DrawingOptionBuilder()
    .withLocation(35.744502, 51.368966)
    .withMapZoom(14)
    .withFillColor(Color.argb(60, 0, 0, 255))
    .withStrokeColor(Color.argb(100, 255, 0, 0))
    .withStrokeWidth(3)
    .withRequestGPSEnabling(false)
    .withDrawingType(currentDrawingType)
    .build(getApplicationContext());
startActivityForResult(intent, REQUEST_CODE);

绘制元素并单击完成后，数据将返回到您的事件

 @Override
protected void onActivityResult(int requestCode, int resultCode, 
Intent data) {
if (resultCode == RESULT_OK && requestCode == REQUEST_CODE && data != 
null) {
DataModel dataModel =
                data.getExtras().getParcelable(MapsActivity.POINTS);
LatLng[] points=dataModel.getPoints();
 }
}

MapDrawingTools

Youtube Demo

快乐编码:)