Google Map v2 缩放以适应所有标记和折线

Question

So, I am showing a route from point A to point B on a Google Map on my Android App. This is all well. What I am doing now is zooming-to-fit both of the markers on the map by doing this:

LatLngBounds.Builder builder = new LatLngBounds.Builder();

for (LatLng marker : markerPoints) {
    builder.include(marker);
}

LatLngBounds bounds = builder.build();
int padding = 20; // offset from edges of the map in pixels
CameraUpdate cu = CameraUpdateFactory.newLatLngBounds(bounds,
        padding);
map.moveCamera(cu);
map.animateCamera(cu);

The problem is that this doesn't include poly lines, so if the route goes outside of the screen, it cuts off the poly line, like this:

Any ideas on how I can zoom-to-fit the poly lines? Thanks!

Answer 1

I tried this code and its works good for me and also i attached output screen here.

LatLng from_Latlng=new LatLng(11.9464816,79.8091988);
LatLng to_Latlong=new LatLng(12.9876327,80.1260089);

LatLngBounds.Builder builder = new LatLngBounds.Builder();
builder.include(from_Latlng);
builder.include(to_Latlong);
LatLngBounds bounds = builder.build();
GoogleMap.animateCamera(CameraUpdateFactory.newLatLngBounds(bounds, 100), 2000, null);

Output screen :-

Answer 2

I got it. I just kept track of every LatLng within my Poly Line and added them to the LatLng builder

private class ParserTask extends
        AsyncTask<String, Integer, List<List<HashMap<String, String>>>> {

    // Parsing the data in non-ui thread
    @Override
    protected List<List<HashMap<String, String>>> doInBackground(
            String... jsonData) {

        JSONObject jObject;
        List<List<HashMap<String, String>>> routes = null;

        try {
            jObject = new JSONObject(jsonData[0]);
            DirectionsJSONParser parser = new DirectionsJSONParser();

            // Starts parsing data
            routes = parser.parse(jObject);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return routes;
    }

    // Executes in UI thread, after the parsing process
    @Override
    protected void onPostExecute(List<List<HashMap<String, String>>> result) {
        ArrayList<LatLng> points = null;
        PolylineOptions lineOptions = null;
        MarkerOptions markerOptions = new MarkerOptions();
        String distance = "";
        String duration = "";

        if (result.size() < 1) {
            Toast.makeText(getBaseContext(), "No Points",
                    Toast.LENGTH_SHORT).show();
            return;
        }

        // Traversing through all the routes
        for (int i = 0; i < result.size(); i++) {
            points = new ArrayList<LatLng>();
            lineOptions = new PolylineOptions();

            // Fetching i-th route
            List<HashMap<String, String>> path = result.get(i);

            // Fetching all the points in i-th route
            for (int j = 0; j < path.size(); j++) {
                HashMap<String, String> point = path.get(j);

                if (j == 0) { // Get distance from the list
                    distance = (String) point.get("distance");
                    continue;
                } else if (j == 1) { // Get duration from the list
                    duration = (String) point.get("duration");
                    continue;
                }

                double lat = Double.parseDouble(point.get("lat"));
                double lng = Double.parseDouble(point.get("lng"));
                LatLng position = new LatLng(lat, lng);

                points.add(position);
            }

            // Adding all the points in the route to LineOptions
            lineOptions.addAll(points);
            lineOptions.width(8);
            lineOptions.color(Color.BLUE);

        }

        tvDistanceDuration.setText("Distance:" + distance + ", Duration:"
                + duration);

        // Drawing polyline in the Google Map for the i-th route
        map.addPolyline(lineOptions);

        LatLngBounds.Builder builder = new LatLngBounds.Builder();
        /*
         * for (Marker marker : markers) {
         * builder.include(marker.getPosition()); }
         */
        for (LatLng point : points) {
            builder.include(point);
        }

        LatLngBounds bounds = builder.build();
        int padding = 20; // offset from edges of the map in pixels
        CameraUpdate cu = CameraUpdateFactory.newLatLngBounds(bounds,
                padding);
        map.moveCamera(cu);
        map.animateCamera(cu, 2000, null);
    }
}

Answer 3

I would say that while you're building the polyline you keep track of the extents of the line. Then when you zoom use those extents not the points.

Answer 4

I copied from Premkumar's for mine. If you've got more than 2 points and you want to make sure everything fits (maybe you've got two points in the middle, and lots of stuff circling around). This solution works by creating a minLatLng and a maxLatLng and then using the newLatLngBounds solution from Premkumar's answer:

var minLat: Double? = null
var minLng: Double? = null
var maxLat: Double? = null
var maxLng: Double? = null
allLocs!!.forEach {
    if (minLat == null) {
        minLat = it.latitude
        maxLat = it.latitude
        minLng = it.longitude
        maxLng = it.longitude
    } else {
        minLat = min(it.latitude, minLat!!)
        maxLat = max(it.latitude, maxLat!!)
        minLng = min(it.longitude, minLng!!)
        maxLng = max(it.longitude, maxLng!!)
    }
}
val builder = LatLngBounds.builder()
builder.include(LatLng(minLat!!, minLng!!))
builder.include(LatLng(maxLat!!, maxLng!!))
googleMap.moveCamera(CameraUpdateFactory.newLatLngBounds(builder.build(), 100))

Obviously, if you need this in real time, it would be far more efficient to keep a tally of your mins and maxes every time you get a new location.