绘制 2 个叠加层之间的路线

Question

在我的应用程序中，我在地图上显示了 2 个位置，并用标记标记了它们。现在，我想画出它们之间的路线，但我不知道该怎么做。我的函数绘制应该是什么样子？

这是我的代码：

package com.ShoppingList.Maps;

import android.content.Context;
import android.graphics.drawable.Drawable;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Point;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.os.Handler;
import android.view.KeyEvent;
import android.widget.TextView;
import android.widget.Toast;

import com.ShoppingList.R;
import com.google.android.maps.GeoPoint;
import com.google.android.maps.ItemizedOverlay;
import com.google.android.maps.MapActivity;
import com.google.android.maps.MapView;
import com.google.android.maps.MyLocationOverlay;
import com.google.android.maps.Overlay;
import com.google.android.maps.OverlayItem;
import com.google.android.maps.Projection;

import java.util.ArrayList;
import java.util.List;

public class OnMap extends MapActivity {
    private MapView map = null;
    private MyLocationOverlay me = null;
    //private myOverlay m = null;

    double latitudine;
    double longitudine;

    double latshop;
    double longshop;

    String nameshop;

    Canvas canvas = null;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.shopsonmap);

        map = (MapView) findViewById(R.id.shopsonmap);

        latitudine = getIntent().getDoubleExtra("latcurent", 0);
        longitudine = getIntent().getDoubleExtra("longcurent", 0);
        latshop = getIntent().getDoubleExtra("latshop", 0);
        longshop = getIntent().getDoubleExtra("longshop", 0);
        nameshop = getIntent().getStringExtra("nameshop");

        GeoPoint p1 = new GeoPoint((int) latitudine, (int) longitudine);
        GeoPoint p2 = new GeoPoint((int) latshop, (int) longshop);

        map.getController().setCenter(getPoint(latitudine, longitudine));
        map.getController().setZoom(15);
        map.setBuiltInZoomControls(true);
        map.setSatellite(false);
        map.setStreetView(true);
        map.invalidate();

        Drawable marker = getResources().getDrawable(R.drawable.marker);

        marker.setBounds(0, 0, marker.getIntrinsicWidth(), marker
                .getIntrinsicHeight());

        map.getOverlays().add(new SitesOverlay(marker));

        me = new MyLocationOverlay(this, map);
        map.getOverlays().add(me);


    }

    /*class myOverlay extends Overlay {
        GeoPoint gp1;
        GeoPoint gp2;

        public myOverlay(GeoPoint gp1, GeoPoint gp2) {

            this.gp1 = gp1;
            this.gp2 = gp2;

        }

        public void draw(Canvas canvas, MapView mapView, boolean shadow) {

            Projection projection = mapView.getProjection();
            Paint mPaint = new Paint();
            Point from = new Point();
            projection.toPixels(gp1, from);
            mPaint.setColor(Color.BLUE);

            Point to = new Point();
            projection.toPixels(gp2, to);
            mPaint.setStrokeWidth(9);
            mPaint.setAlpha(120);
            canvas.drawLine(from.x, from.y, to.x, to.y, mPaint);
            super.draw(canvas, mapView, shadow);

        }
    }*/

    @Override
    public void onResume() {
        super.onResume();

        me.enableCompass();
    }

    @Override
    public void onPause() {
        super.onPause();

        me.disableCompass();
    }

    @Override
    protected boolean isRouteDisplayed() {
        return (false);
    }

    private GeoPoint getPoint(double lat, double lon) {
        return (new GeoPoint((int) (lat * 1000000.0), (int) (lon * 1000000.0)));
    }

    private class SitesOverlay extends ItemizedOverlay<OverlayItem> {
        private List<OverlayItem> items = new ArrayList<OverlayItem>();
        private Drawable marker = null;

        public SitesOverlay(Drawable marker) {
            super(marker);
            this.marker = marker;

            items.add(new OverlayItem(getPoint(latitudine, longitudine),
                    "Your location", "You are here!"));

            items.add(new OverlayItem(getPoint(latshop, longshop), "The shop",
                    "The shop " + nameshop + " is here"));

            populate();
        }

        @Override
        protected OverlayItem createItem(int i) {
            return (items.get(i));
        }

        @Override
        public void draw(Canvas canvas, MapView mapView, boolean shadow) {

            super.draw(canvas, mapView, shadow);

            boundCenterBottom(marker);
        }

        @Override
        protected boolean onTap(int i) {
            Toast.makeText(OnMap.this, items.get(i).getSnippet(),
                    Toast.LENGTH_SHORT).show();

            return (true);
        }

        @Override
        public int size() {
            return (items.size());
        }
    }
}

谢谢..

Answer 1

因此，假设您正在从 REST Web 服务获取位置（以 JSON 格式）。为此，我使用 Volley 库来连接并获取服务器的响应。

JSONArray 响应示例：

[ {...,"位置":"44.924654,8.586219", ...},
{...,"位置":"44.906177,8.157752", ...},
{...，“位置”：“44.906177,8.157752”，...}，{...，“位置”：
"44.956733,7.876227", ...}, {...,"位置": "45.034424,7.671607",
...}]

该步骤是将第一个和最后一个位置设置为标记，中间位置将在它们之间绘制线。

因为位置是作为字符串获取的，所以我们首先要分割字符串，并将“，”之前的部分分配给纬度，其余部分分配给经度。

                    public void onResponse(JSONArray response) {

                    if (response.length() > 0) {
                        try {
                            //creating the markers: for this I need the first and the last location
                            JSONObject firstLocationJson = response.getJSONObject(0);
                            JSONObject lastLocationJson = response.getJSONObject(response.length() - 1);

                            String[] firstLocationLatLng = firstLocationJson.getString("location").split(",");
                            Location firstLocation = new Location(LocationManager.GPS_PROVIDER);
                            firstLocation.setLatitude(Double.parseDouble(firstLocationLatLng[0]));
                            firstLocation.setLongitude(Double.parseDouble(firstLocationLatLng[1]));

                            String[] lastLocationLatLng = lastLocationJson.getString("location").split(",");
                            Location lastLocation = new Location(LocationManager.GPS_PROVIDER);
                            lastLocation.setLatitude(Double.parseDouble(lastLocationLatLng[0]));
                            lastLocation.setLongitude(Double.parseDouble(lastLocationLatLng[1]));

                            final float distance = firstLocation.distanceTo(lastLocation); //distance in meters

                            if (distance > 50000 && distance < 200000) { //distance bigger than 50 km
                                showMapView(response, firstLocation, lastLocation, 7);
                            } else if (distance > 300000) {
                                showMapView(response, firstLocation, lastLocation, 5);
                            }
                        } catch (JSONException e) {
                            // TODO
                        }
                    }
                    // TODO -
                }

现在让我们看看绘制 MapView 的方法。请注意，我不在活动内，如果我想强制代码在主线程上运行（用于更新 UI），我将使用 Handler 和 Runnable。
showMapView() 方法负责绘制标记及其之间的位置。

    private void showMapView(JSONArray response, Location firstLoc, Location lastLoc, final int zoom) {
    final LatLng latLng1 = new LatLng(firstLoc.getLatitude(), firstLoc.getLongitude());
    final LatLng latLng2 = new LatLng(lastLoc.getLatitude(), lastLoc.getLongitude());
    final MarkerOptions marker1 = new MarkerOptions().position(latLng1);
    final MarkerOptions marker2 = new MarkerOptions().position(latLng2);

    final PolylineOptions polylineOptions = new PolylineOptions();
    final ArrayList<LatLng> points = new ArrayList<LatLng>();
    //saving all the locations in an ArrayList
    if (response.length() > 0) {
        for (int i = 0; i < response.length(); i++) {
            JSONObject locationsJson = null;
            try {
                locationsJson = response.getJSONObject(i);
            } catch (JSONException e) {
                e.printStackTrace();
            }
            String locationString = null;
            try {
                locationString = locationsJson.getString("location");
            } catch (JSONException e) {
                e.printStackTrace();
            }
            //here I am splitting the location string in a String array. 
            String[] locationLatLng = locationString.split(",");
            Location loc = new Location(LocationManager.GPS_PROVIDER);
            loc.setLatitude(Double.parseDouble(locationLatLng[0]));
            loc.setLongitude(Double.parseDouble(locationLatLng[1]));
            LatLng latLng = new LatLng(loc.getLatitude(), loc.getLongitude());
            points.add(latLng);

        }
    }

    Handler mainHandler = new Handler(Looper.getMainLooper());

    Runnable myRunnable = new Runnable() {
        @Override
        public void run() {
            mapView.getMapAsync(new OnMapReadyCallback() {
                @Override
                public void onMapReady(GoogleMap googleMap) {
                    googleMap.addMarker(marker1);
                    googleMap.addMarker(marker2);
                    googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(latLng1, zoom));
                    googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(latLng2, zoom));
                    polylineOptions.addAll(points);
                    polylineOptions.width(10);
                    polylineOptions.color(Color.BLUE);
                    googleMap.addPolyline(polylineOptions);
                }
            });
        }
    };

    mainHandler.post(myRunnable);
}

代码简单明了，点（中间位置）是使用 PolylineOptions 类型的对象绘制的，并使用以下行将其添加到地图中： googleMap.addPolyline(polylineOptions);

所需的缩放级别，范围为 2.0 至 21.0。低于此范围的值设置为 2.0，高于此范围的值设置为 21.0。增加值以放大。并非所有区域都具有最大缩放级别的图块。
在此处阅读有关缩放的信息

Answer 2

我已经给出了这个问题的答案，请阅读以下链接

在 android 中的谷歌地图中的两点之间绘制线

我希望这有帮助。