WEBVTT 00:00.080 --> 00:01.120 Welcome back. 00:01.160 --> 00:09.040 After we created this directions module, let's move to the map view model and inject the constructor 00:09.040 --> 00:10.840 with this repository. 00:10.840 --> 00:19.640 So here private val directions repository and import the directions repository. 00:19.640 --> 00:25.080 Scroll down in order to create the functions for the directions package. 00:25.280 --> 00:35.880 So here directions API we need to fetch the route to marker and the multiple route to markers okay. 00:36.080 --> 00:45.800 So first of all private Val route which is of type mutable state flow list of lat long and the route 00:45.840 --> 00:46.600 points. 00:46.760 --> 00:49.400 So let me name it route points. 00:50.040 --> 00:52.000 This route points. 00:52.000 --> 00:57.560 Here we are creating an observable data stream for tracking route points. 00:57.760 --> 01:04.330 This is very important because we need to keep tracking for the root points. 01:04.330 --> 01:07.410 Why we are doing this pattern here. 01:07.450 --> 01:09.050 Underscore root points. 01:09.050 --> 01:10.250 Private banking. 01:10.250 --> 01:15.730 Property conversion, a convention with underscore and mutable state. 01:15.730 --> 01:24.330 Flow a mutable container that holds a state and emits updates to collectors returning a or of type list. 01:24.370 --> 01:31.690 Lat long type represents nullable list of geographic coordinates initialized with null. 01:31.850 --> 01:43.290 So this is a public read only state flow exposes read only version to external components as state flow, 01:43.290 --> 01:49.970 and as state flow function converts mutable flow to immutable. 01:49.970 --> 01:55.410 Consumers can observe changes but can't modify directly. 01:55.410 --> 01:58.010 So this is a very important note. 01:58.170 --> 02:05.690 And it's commonly used this this pattern commonly used in many applications, and we talked about it 02:05.690 --> 02:13.610 in the previous videos so consumers can observe changes but can't modify directly. 02:13.610 --> 02:24.810 Then create a new function, name it as fetch to or from current position to marker. 02:25.010 --> 02:29.130 Taking a marker as a lat long parameter. 02:29.130 --> 02:39.370 And inside this function, we need to use the ViewModel scope in order to call the directions dot get 02:39.530 --> 02:40.210 route. 02:40.250 --> 02:46.330 If you remember from the directions repository implementation, we have two functions. 02:46.370 --> 02:50.330 Get route for multiple markers and get route. 02:50.450 --> 02:58.690 Here we inside this get route, we are fetching the data from the origin to the destination. 02:58.690 --> 03:06.620 The origin would be the current position of the user and the destination is the selected marker. 03:06.780 --> 03:10.020 So here inside this function. 03:10.300 --> 03:14.420 Let's start with ViewModel scoop dot launch. 03:14.460 --> 03:23.220 Also, if you remember, we made those functions as suspend functions inside this directions repository 03:23.220 --> 03:24.180 implementation. 03:24.340 --> 03:28.860 So for this purpose we need to call them from the ViewModel scoop. 03:28.900 --> 03:38.940 This ViewModel scoop start with location repository dot user location dot value. 03:38.940 --> 03:43.140 And here we are executing the let block. 03:43.340 --> 03:53.220 If the location repository dot user location not equals to the not equals to the uh to null, then we 03:53.220 --> 03:55.860 need to execute this block. 03:56.100 --> 03:57.620 What we need to create. 03:57.660 --> 04:08.540 We need to set the current location as a parameter of this lambda expression and go and create val root 04:08.580 --> 04:11.380 equals to directions. 04:11.780 --> 04:16.740 Data or directions repository dot get root. 04:16.820 --> 04:21.260 Inside this function pass the origin and destination. 04:21.260 --> 04:22.580 What is the origin? 04:22.860 --> 04:25.980 The current location and what is the destination? 04:26.260 --> 04:30.660 The marker that is passed as a parameter for this function. 04:30.660 --> 04:37.540 Then let me check if this root doesn't equal to null. 04:37.700 --> 04:38.900 What we need to do. 04:39.060 --> 04:45.540 We need to set the root points dot value equals to the root. 04:45.580 --> 04:56.460 Otherwise, display a log message with tag as tag and could not calculate root or root is null. 04:56.500 --> 05:00.020 Then we need to check for running. 05:00.180 --> 05:06.230 So run log v location or user location is not. 05:06.350 --> 05:09.670 So this is how we implement this function. 05:09.670 --> 05:12.430 Fetch route from current position to marker. 05:12.670 --> 05:19.390 This function takes the marker that the destination marker for uh where we need to go. 05:19.750 --> 05:22.110 We need to go to that destination marker. 05:22.390 --> 05:30.630 And here we are launching the ViewModel scope in order to execute the location repository, get route 05:30.630 --> 05:32.630 because it's a suspend function. 05:32.790 --> 05:36.030 And we need to get the user location. 05:36.030 --> 05:43.190 So we need to fetch and call this route the origin, the current location of the user. 05:43.230 --> 05:47.590 The destination is the marker that it's passed as a parameter. 05:47.590 --> 05:52.950 If the route is not null, go and store it inside the variable route points. 05:52.950 --> 05:57.470 If it is not, if it is null, go and and display. 05:57.470 --> 05:59.270 The route is null.