Book Image

Dart By Example

By : David Mitchell
Book Image

Dart By Example

By: David Mitchell

Overview of this book

Table of Contents (17 chapters)
Dart By Example
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Plotting the user's location


Most mobile devices are fitted with a geolocation device, or the location can be determined using secondary information such as IP or even falling back to user input. This is exposed for the modern web developer to use in applications via the HTML5 geolocation API at http://www.w3.org/TR/geolocation-API/.

As with the desktop notifications, the user must give permission for the page to use their location. A further little hurdle is that location features do not work on Dartium. To try out this feature of the application, use pub build to create the JavaScript version and use another browser:

The Locate button on the page will attempt to obtain the user's position and draw it on the page by adding it to the featurePlotter class instance:

locateUser(Event evt) async {
  Geoposition geoPos = await window.navigator.geolocation.getCurrentPosition();
  MapIndicator mapIndicator;
  var pos =
      featPlotter.toPoint(geoPos.coords.longitude, geoPos.coords.latitude);
  mapIndicator...