Question: In my application, I am starting the Google Navigation with the help of following set of code.

```
String uri = "http://maps.google.com/maps?saddr="+ gpsLatitude
            + "," + gpsLongitude
            + "&daddr="
            + updateAcceptedOfferDetailsData.getDestinationLat()+","+updateAcceptedOfferDetailsData.getDestinationLon();
            Intent intent = new Intent(android.content.Intent.ACTION_VIEW,
                    Uri.parse(uri));
            intent.setClassName("com.google.android.apps.maps",
            "com.google.android.maps.MapsActivity");
            startActivity(intent);

```

I am passing the Source Lat/Lng and Destination Lat/Lng of the respective addresses.

**Problem:-** Here my problem is when the Navigation Screen opens there is no option to **"Start"** rather there is another option **"Preview"**, This problem do not happens at all the places it works fine for some places but not for all. May I know what the whole mess is??

Thanks

Answer: 
I have done some research on this and it appears that there is no way around it. The preview button will appear wherever navigation is not available for the requested route, the only reliable source I could find (Google was not massively helpful on this) to prove this is [here](https://support.google.com/gmm/answer/2839865?hl=en&ref_topic=3137719) which states (under navigation):

> 
> To launch turn-by-turn navigation, touch the Start navigation button represented by a chevron in the bottom right of the screen. When Navigation is not available, the icon will appear as a preview arrow , and you can view the directions step by step.
> 
> 
> 

The only suggestion that I have would be to somehow check whether or not navigation is in fact available for the given route prior to passing to the maps application, and if not then display a prompt to the user, but I do not know the android API's well enough to be of any help here. 

[A list of supported countries and territories is available here.](https://support.google.com/gmm/answer/172221?hl=en-GB) 

Hope this helps.
I'm glad I found this thread which gave me the right solution.  

I had created a route on my PC and sent it to my phone.  

When I tried to start it, it only showed the Preview option but no Start.  

To solve it, I edited the stops, added my location and moved it to the top as the starting point.  

Then I clicked on "Done" and the Start button was shown.