Driving Directions in Android 0.9 SDK

Friday August 22, 2008 at 11:35 PM

Driving directions are going to be a big deal in Android, and showing them from applications is a must-have for several applications. For example, in my CompareEverywhere app, I’m showing directions from your current location to nearby stores.

For earlier SDKs, Nicolas Gramlich put together a tutorial to get access to the com.google.googlenav.DrivingDirection class and render an overlay onto a normal MapView. In the newest 0.9 SDK, this class isn’t public anymore, which means no more access to raw driving directions for developers. (There is an alternate method of getting raw data if you’re really interested.)

Nicolas also put together an awesome entry called AndNav for the Developer Challenge, but sadly it appears that real-time navigation systems go against the Google Maps Terms of Service which says “you may not use Google Maps with any applications capable of real time route guidance” (edited slightly). I’m sure this is an upstream restriction from Google’s data sources, as they want to protect their market for other in-vehicle navigation devices. Don’t worry, the iPhone suffers from this same restriction.

So how can Android applications show driving directions? It’s actually pretty simple, although not yet documented. If you launch a normal URL to the Google Maps website, Android will intercept and ask you if you really want to use the browser, or instead be directed over to the Android Maps app:

this.startActivity(new Intent(Intent.ACTION_VIEW,
	Uri.parse("http://maps.google.com/maps?f=d&saddr=37.4,-121.9
		&daddr=Bellevue, WA&hl=en")));

Just tap “Maps” option and your route will be calculated and shown on the device, screenshots below. You could easily use a LocationListener to keep track of your current latitude/longitude, and pass that as the starting address. Thanks to Daniel Switkin at Google for helping me find this gem.