WEBVTT 00:00.080 --> 00:01.120 Welcome back. 00:01.120 --> 00:03.680 Now let's continue with the retrofit. 00:03.680 --> 00:09.320 And in this video we're going to create the second part of retrofit package which is the directions 00:09.320 --> 00:10.120 response. 00:10.120 --> 00:13.360 Create a new class data class. 00:13.360 --> 00:16.880 Name it as directions response. 00:16.920 --> 00:23.720 Let's start with the routes which is of type list of routes. 00:23.720 --> 00:27.560 And let's define the data class routes here. 00:27.800 --> 00:34.320 Create a new data class called route and start with not routes. 00:34.360 --> 00:42.280 Start with route and val over view polyline which is of type polyline. 00:42.280 --> 00:49.560 And here another data class which is poly val points. 00:49.560 --> 00:51.280 It's of type string. 00:51.360 --> 00:59.200 If you imported the polyline from Google Maps, please remove it because I am going to import this data 00:59.200 --> 00:59.560 class. 00:59.560 --> 01:06.240 So Alt plus enter to import the class, not the model class that we create here. 01:06.240 --> 01:08.770 It's of type poly line. 01:08.810 --> 01:09.370 Okay. 01:09.570 --> 01:15.450 So in order to distinguish it I made as poly L capital okay. 01:15.490 --> 01:18.290 So to reuse this data class. 01:18.450 --> 01:26.490 So this data class use the root and this root data class use polyline which is the third data class. 01:26.730 --> 01:32.370 Now let's explain why we created those three data classes. 01:32.490 --> 01:39.130 These data classes model the structure of the response from the Google Maps Directions API. 01:39.330 --> 01:41.570 Go back to the response. 01:41.730 --> 01:45.490 And here we have the Geocoded points. 01:45.490 --> 01:53.490 If you if you remember the key and the value from JSON syntax the key and the value. 01:53.610 --> 01:58.450 And here we are referring to the root which is the list of root. 01:58.450 --> 02:07.890 And if you remember, this is the JSON syntax where every element refers in this list as a root element 02:07.890 --> 02:09.970 inside this root list. 02:09.970 --> 02:11.290 So this is the array. 02:11.530 --> 02:16.330 Every element in this array correspond to the root elements. 02:16.370 --> 02:16.890 Okay. 02:17.090 --> 02:21.370 If you scroll down, you will get those roots. 02:21.370 --> 02:30.890 And if you click on Prettyprint it will define maybe would be better, but you can use different websites 02:30.890 --> 02:32.570 in order to identify it. 02:32.570 --> 02:39.610 So please refer to the previous videos in order in order to learn more about JSON syntax. 02:39.810 --> 02:48.050 But I am showing you how to, uh, to learn the response and how to model the response. 02:48.050 --> 02:49.010 The routes. 02:49.010 --> 02:55.890 And this is a list of routes I defined a model class called route, which is of the which is of type 02:55.930 --> 02:57.330 overview polyline. 02:57.490 --> 03:04.930 If we go here we have the polyline and the polyline gives us the points. 03:04.930 --> 03:09.570 So every polyline have or has the points okay. 03:09.770 --> 03:15.010 So here again guys I get the polyline polyline and so on. 03:15.010 --> 03:22.860 So every route contains polyline that should be displayed in our application. 03:23.060 --> 03:32.420 So the purpose representing the entire response from the directions API, the routes value a list of 03:32.420 --> 03:37.660 possible routes usually contains one route unless you request alternatives. 03:37.860 --> 03:39.140 Why a list? 03:39.180 --> 03:46.660 The API can return multiple route options if you set alternatives equals to true in your request. 03:46.820 --> 03:48.020 Other common fields. 03:48.020 --> 03:51.700 The status you can define the status if you go up. 03:51.980 --> 03:53.860 So let me scroll up. 03:54.020 --> 03:58.740 If you notice here we have routes. 03:58.780 --> 04:03.260 If you scroll down we can get the statuses okay. 04:03.500 --> 04:13.420 So again guys you can add more and more things like status warning waypoints, order and so on. 04:13.460 --> 04:21.180 But I'm showing you the most important and simple thing from API response. 04:21.180 --> 04:30.220 The route represents a single route between origin and destination, so this is the single route between 04:30.340 --> 04:32.660 origin and destination. 04:32.820 --> 04:43.300 The overview polyline contains this for the single route, and the overview polyline contains the encoded 04:43.300 --> 04:46.580 polyline path of the entire route. 04:46.620 --> 04:47.340 Legs. 04:47.420 --> 04:49.100 List of route segments. 04:49.100 --> 04:50.020 Bounds. 04:50.060 --> 04:54.380 Geographic rectangle that contains the entire route. 04:54.700 --> 04:57.780 The Copyright's attribution text. 04:57.860 --> 04:58.860 Warnings. 04:58.860 --> 05:01.340 Any route specific warnings. 05:01.380 --> 05:02.100 Fair. 05:02.300 --> 05:03.420 Public transit. 05:03.460 --> 05:03.860 Fair. 05:03.900 --> 05:05.780 Information, if applicable. 05:05.820 --> 05:13.260 Okay, so there are a lot of things you can implement in this JSON response. 05:13.300 --> 05:13.820 Okay. 05:14.100 --> 05:24.180 The polyline contains the compressed representation of the route's path points and encoded string using 05:24.340 --> 05:26.700 Google's polyline algorithm. 05:26.740 --> 05:28.380 Highly compressed format. 05:28.380 --> 05:31.340 Reduces data size significantly. 05:31.540 --> 05:34.820 Needs to be decoded before use on a map. 05:34.980 --> 05:40.430 For example, included encoded string might look like this. 05:40.470 --> 05:41.310 Encoded. 05:41.550 --> 05:42.670 So scroll down. 05:42.670 --> 05:45.310 And this is the encoded text okay. 05:45.510 --> 05:50.910 Now I want from you to understand why this structure matters. 05:51.150 --> 05:58.350 For efficiency the polyline encoding dramatically reduces data transfer size flexibility. 05:58.350 --> 06:05.550 The nested structure allows for complex route information extensibility. 06:05.750 --> 06:15.110 Easy to add more fields as you need growth and Kotlin data classes provide compile time checking. 06:15.150 --> 06:22.150 Most real world implementations include more fields, for example status error message, legs bound, 06:22.190 --> 06:24.430 copyrights warning, and others. 06:24.430 --> 06:30.390 But we are interested in this simple API response. 06:30.390 --> 06:34.750 Later, we're going to add more and more things like the waypoints. 06:34.750 --> 06:42.590 So here we have created the three data classes and the Data Directions Service interface.