RouteDrawer wraps Google Directions API (https://developers.google.com/maps/documentation/directions/) using RxJava for Android so developers can download, parse and draw path on the map in very fast and flexible way (For now only JSON support).
The library contains two main parts.
-
RouteApi is responsible for sending request to Google's Direction API and handling the response
-
DrawerApi is responsible for drawing the path on the map
If you are using gradle you have to add this one line of code to your build.gradle file under dependencies section:
compile 'com.github.polok.routedrawer:library:1.0.0'In other case you have to take whole library project.
First we have to download the path. For this we need to provide two points (start and end) and travel mode.
public interface RouteApi {
Observable<String> getJsonDirections(final LatLng start, final LatLng end, final TravelMode mode);
}Where travel mode can be:
public enum TravelMode {
DRIVING,
WALKING,
BICYCLING,
TRANSIT
}As you can see the above method returns Observable and our response is a String. So far so good, we downloaded the route but what the hell - response as String, I don't want to parse it on my own.
With RxJava and some transformations nothing more easily.
Have a look:
routeRest.getJsonDirections(new LatLng(50.126922, 19.015261), new LatLng(50.200206, 19.175603), TravelMode.DRIVING)
.observeOn(AndroidSchedulers.mainThread())
.map(new Func1<String, Routes>() {
@Override
public Routes call(String s) {
return new RouteJsonParser<Routes>().parse(s, Routes.class);
}
})
.subscribe(new Action1<Routes>() {
@Override
public void call(Routes r) {
...
}
});The most important part here is
...
.map(new Func1<String, Routes>() {
@Override
public Routes call(String s) {
return new RouteJsonParser<Routes>().parse(s, Routes.class);
}
})For more details about 'map' operator can be find here - https://github.com/ReactiveX/RxJava/wiki/Transforming-Observables#map In short, we parse our response to Routes object, so now we can go to draw the path on the map.
Here we have to use DrawerApi which for now provides one method:
void drawPath(Routes routes);(for now it forces to use Routes object).
We are almost there but before we invoke draw method we have to build our drawer using RouteDrawerBuilder. It allows us to customize a little bit the path and the markers. It requires to get GoogleMap(!) and if we want we can provide
- marker icon
- path width
- path color
- marker alpha
This can look as
final RouteDrawer routeDrawer = new RouteDrawer.RouteDrawerBuilder(googleMap)
.withColor(Color.BLUE)
.withWidth(8)
.withAlpha(0.5f)
.withMarkerIcon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_ORANGE))
.build();And taking all together:
private GoogleMap googleMap;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
googleMap = ((MapFragment) getFragmentManager().findFragmentById(R.id.map)).getMap();
final RouteDrawer routeDrawer = new RouteDrawer.RouteDrawerBuilder(googleMap)
.withColor(Color.BLUE)
.withWidth(8)
.withAlpha(0.5f)
.withMarkerIcon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_ORANGE))
.build();
RouteRest routeRest = new RouteRest();
routeRest.getJsonDirections(new LatLng(50.126922, 19.015261), new LatLng(50.200206, 19.175603), TravelMode.DRIVING)
.observeOn(AndroidSchedulers.mainThread())
.map(new Func1<String, Routes>() {
@Override
public Routes call(String s) {
return new RouteJsonParser<Routes>().parse(s, Routes.class);
}
})
.subscribe(new Action1<Routes>() {
@Override
public void call(Routes r) {
routeDrawer.drawPath(r);
}
});
}