Kivy / Google Maps integration

Example that shows how to integrate Google Maps within a Kivy application. Currently works only on Android.

Work in progress

Configuration

• Configure your package.name and package.domain. The sum of both should not be more than 20 characters, or Google Maps API will not work:

    package.name = kivygmaps
    package.domain = com.mr
  

• Follow the Android Maps API v2 documentation to get your Android Maps API key

• Put your API Key into buildozer.spec in [app:android.meta_data] section as com.google.android.maps.v2.API_KEY:

    [app:android.meta_data]
    com.google.android.maps.v2.API_KEY = YOURAPIKEYHERE
  

Usage

The gmaps module provide a GMap widget that you can directly use into your application. Right now, you can add only one GMap per application, on an transparent background. If you cover the background, the widget will not be shown. Here is an hello world example:

import gmaps
from kivy.app import App

class HelloGmaps(App):
    def build(self):
        self.map_widget = GMap()
        self.map_widget.bind(on_ready=self.create_some_markers)
        return self.map_widget

    def create_some_markers(self, map_widget):
        # get the google map interface
        sydney = map_widget.create_latlng(-33.867, 151.206)
        marker = map_widget.create_marker(
            title='Sydney',
            snippet='The most populous city in Autralia',
            position=sydney)
        map_widget.map.addMarker(marker)

if __name__ == '__main__':
    HelloGmaps().run()

Threads

All the operation done on the map must be done within the internal thread of the android widget. It means, you cannot interact directly from Kivy. You can create object (LatLng, Marker..), but interact with the map must stay in the map thread.

All the event fired by the GMap are happening in the map thread. For example, if you bind to the GMap.on_map_click, your callback will be already in the map thread. If you want to call a method within the map thread, you can use GMap.execute() method. You cannot return values from it, and the call will be asynchronous:

map = GMap()
def my_func(...):
    pass
map.execute(my_func)

You can also decorate your function with android.runnable.run_on_ui_thread, or GMap.run_on_ui_thread:

from android.runnable import run_on_ui_thread

@run_on_ui_thread
def set_position(self, lat, lng):
    pos = self.map_widget.create_latlng(lat, lng)
    self.map_widget.map.moveCamera(
        self.map_widget.camera_update_factory.newLatLngZoom(
        pos, 13))

When the Android Google Maps widget is created, it will fire an event name on_ready. This is where you can create markers, change the camera, and so on.

Events

Supported Google Maps events are:

• on_camera_change(CameraPosition) (not working yet)
• on_info_window_click(Marker)
• on_map_click(LatLng)
• on_map_loaded() (not working yet)
• on_map_long_click(Marker)
• on_marker_click(Marker)
• on_marker_drag(Marker)
• on_marker_drag_end(Marker)
• on_marker_drag_start(Marker)
• on_my_location_button_click

All the events are dispatched in the map thread, not the kivy main thread.

Utils

The GMap have some methods to create java object easily, such as:

• GMap.create_latlng(lat, lng) - Create a LatLng object
• GMap.create_marker(**options) Create a Marker object, with all the key=value in options

Authors

• Mathieu Virbel, Melting Rocks
• Thomas Hansen, Fresk