Using Google's Places Autocomplete API to find directions

I'm currently integrating Google's Places Autocomplete API into the FuelMyRoute Android app. This way as soon as a user starts typing a destination, the location will autocomplete.

The Places Autocomplete API response is something like this:

{
"predictions" : [
    {
        "description" : "Barnes & Noble, East 3rd Street, Bloomington, IN, United States",
        "id" : "5c94b4b6d6ffdc0402451f0ccacd65d04c92b1be",
        "matched_substrings" : [
            {
            "length" : 6,
            "offset" : 0
            }
        ],
        "reference" : "CoQBeAAAAIcYT-uv-ryTSOBQ8Cl3W313c9fuh-J5KCY8N0k-QDVPWGD65lIgs9ZpXar6eIMJ3ey5HL-3d1yMChPIwcO9uDSFdyl_NeHcOgpSFVfqsbBh-E_F0QfVviuZHGPicPRLsGvEXP5jC6NuBZ2-0jQnxVzRNN-6W9XaXxFURgW115mLEhD3vouWuAImM-yWSat1opedGhROZAG_tNmuisZo82H0DOvw-yqj5Q",
        "terms" : [
            {
            "offset" : 0,
            "value" : "Barnes & Noble"
            },
            {
            "offset" : 16,
            "value" : "East 3rd Street"
            },
            {
            "offset" : 33,
            "value" : "Bloomington"
            },
            {
            "offset" : 46,
            "value" : "IN"
            },
            {
            "offset" : 50,
            "value" : "United States"
            }
        ],
        "types" : [ "establishment", "geocode" ]
    },
    ...

I was then feeding the description (in the case above, Barnes & Noble, East 3rd Street, Bloomington, IN, United States) as the destination to Google's Directions API.

However, this turns out to only work sometimes. The description returned by the Autocomplete API is not necessarily detailed enough to resolve to a geocoded address.

What you need to do instead is take the reference field for a location and pass it to yet another API, the Place Details API. These request URLs look like

https://maps.googleapis.com/maps/api/place/details/json?\
    reference=CoQBeAAAAIcYT...&sensor=true&key=API_KEY_HERE

The result of which looks like this

{
"html_attributions" : [],
"result" : {
    "address_components" : [
        {
            "long_name" : "2813",
            "short_name" : "2813",
            "types" : [ "street_number" ]
        },
        {
            "long_name" : "E 3rd St",
            "short_name" : "E 3rd St",
            "types" : [ "route" ]
        },
        {
            "long_name" : "Bloomington",
            "short_name" : "Bloomington",
            "types" : [ "locality", "political" ]
        },
        {
            "long_name" : "IN",
            "short_name" : "IN",
            "types" : [ "administrative_area_level_1", "political" ]
        },
        {
            "long_name" : "United States",
            "short_name" : "US",
            "types" : [ "country", "political" ]
        },
        {
            "long_name" : "47408",
            "short_name" : "47408",
            "types" : [ "postal_code" ]
        }
    ],
    "adr_address" : "\u003cspan class=\"street-address\"\u003e2813 E 3rd St\u003c/span\u003e, \u003cspan class=\"locality\"\u003eBloomington\u003c/span\u003e, \u003cspan class=\"region\"\u003eIN\u003c/span\u003e \u003cspan class=\"postal-code\"\u003e47408\u003c/span\u003e, \u003cspan class=\"country-name\"\u003eUnited States\u003c/span\u003e",
    "formatted_address" : "2813 E 3rd St, Bloomington, IN, United States",
    "formatted_phone_number" : "(812) 331-0669",
    "geometry" : {
        "location" : {
            "lat" : 39.165632,
            "lng" : -86.49625899999999
        }
    },
    ...

You can get the latitude/longitude from geometry.location (also the formatted_address would likely work as well as a destination in a Directions API request). Now you can make a Directions API request with an exact destination.