我正在尝试在Google map 的左上角显示一个TextView,以告知用户距特定标记点位置x距离的距离,即“您靠近位置A”,但仅在范围内显示TextView。如果它们超出范围,则TextView将消失。

我了解Google Places API会向您显示所有附近的位置,但是我只想显示用户在 map 上具有x距离的标记在附近的位置。

我怎样才能做到这一点?我仍然需要使用Google Places API吗?

我的类(class).java:

private GoogleMap mMap;

private LatLng currLocation;

private static final LatLng POINTA = new LatLng(32.820193, -117.232568);
private static final LatLng POINTB = new LatLng(32.829129, -117.232204);
private static final LatLng POINTC = new LatLng(32.821114, -117.231534);
private static final LatLng POINTD = new LatLng(32.825157, -117.232003);

// Array to store hotspot coordinates
private ArrayList<LatLng> markerCoords = new ArrayList<LatLng>();
private static final int POINTS = 4;

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

    setUpMapIfNeeded();
}

@Override
public boolean onCreateOptionsMenu(Menu menu)
{
    // Create MenuInflater object to insert ActionBar buttons
    MenuInflater inflater = getMenuInflater();

    // Display the ActionBar buttons from .xml
    inflater.inflate(R.menu.menu_map, menu);

    return true;
}

@Override
protected void onResume()
{
    super.onResume();
    setUpMapIfNeeded();

}

private void setUpMapIfNeeded()
{
    if (mMap == null)
    {
        mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
                .getMap();

        // Check if we were successful in obtaining the map.
        if (mMap != null)
        {
            markerCoords.add(POINTA);
            markerCoords.add(POINTB);
            markerCoords.add(POINTC);
            markerCoords.add(POINTD);

            setUpMap();
        }
    }
}
private void setUpMap()
{
    // Set My Location blue dot
    mMap.setMyLocationEnabled(true);

    LocationManager locationManager = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
    Criteria criteria = new Criteria();
    String provider = locationManager.getBestProvider(criteria, true);
    Location myLocation = locationManager.getLastKnownLocation(provider);

    if (myLocation != null)
    {
        double latitude = myLocation.getLatitude();
        double longitude = myLocation.getLongitude();
        currLocation = new LatLng(latitude, longitude);
    }

    for (int i = 0; i < POINTS; i++)
    {
        mMap.addMarker(new MarkerOptions()
                .position(markerCoords.get(i))
                .icon(BitmapDescriptorFactory.fromResource(R.drawable.post_it_marker)));
    }
}

map.xml
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <fragment
        xmlns:map="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/map"
        android:name="com.google.android.gms.maps.SupportMapFragment"
        map:cameraTargetLat="32.881416"
        map:cameraTargetLng="-117.237428"
        map:cameraZoom="15"
        map:mapType="normal" />
</RelativeLayout>

有人可以指出我正确的方向吗?谢谢

最佳答案

简短答案location.distanceTo(anotherLocation)
我建议在setupMap中添加其他监听器,以一种简单的方式获取所有位置更改。

mMap.setMyLocationEnabled(true);
mMap.setOnMyLocationChangeListener(this);

然后,在此监听器中,您只需在当前位置和目标之间进行测量即可。距离(以米为单位)。
@Override
public void onMyLocationChange(Location location) {
    Location target = new Location("target");
    for(LatLng point : new LatLng[]{POINTA, POINTB, POINTC, POINTD}) {
        target.setLatitude(point.latitude);
        target.setLongitude(point.longitude);
        if(location.distanceTo(target) < METERS_100) {
            // bingo!
        }
    }
}

当然,您应该将自己的 Activity 设为implements GoogleMap.OnMyLocationChangeListener

关于java - 如何不断从Google Maps Android中的当前位置检测附近的标记位置?,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/32284708/

10-12 01:45
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