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Adding a New Data Model Object7:18 with Ken Alger
Add a new data model object to the project to handle the daily weather forecast.
As I mentioned, we'll continue to use the Dark Sky API to get weather data for 0:00 this project. 0:04 The response we get from this API gives us a list of hourly forecast for 0:06 the next two days, which is perfect as it's just what we need. 0:10 We're already getting this data in the JSON response. 0:14 We just haven't accessed it yet. 0:17 Let's start by adding this new data to our data model. 0:20 Let's take a look at the JSON data we get from the Dark Sky API. 0:24 If you don't already have an account, 0:28 sign up at darksky.net/dev/register for a free account. 0:32 Once you've logged in, we want to click on the personal test URL here 0:37 in the dashboard, to view weather data for Alcatraz Island in California. 0:41 Now that I'm using an extension for 0:50 the chrome browser, called JSON viewer, to make this JSON data look a bit nicer. 0:52 It's linked in the teachers notes, 0:57 our stormy app is currently using the data from this currently object. 1:00 We now want to add hourly forecast. 1:08 As luck will have it, there's an array of hourly forecast objects. 1:11 There's a lot here, but we'll just pick a few key pieces of information. 1:16 Remember, if you want more details about any of the data in this API, 1:21 we can head back to the developer dashboard, Click on documentation, 1:25 and The Response Format, where we can read about all the different data points. 1:34 Let's go back and look at our hourly forecast object again. 1:41 So here we see, we have an array of JSON objects, 1:51 as designated by the square bracket. 1:54 This makes for a nice and direct translation. 1:56 We'll use an array of Java objects inside our data model. 1:59 Each object will be an hour item that will hold the time, 2:04 a short summary of the weather conditions, the temperature, and the weather icon. 2:07 Let's head to Android Studio and get started. 2:13 We need to add to the apps data model to hold this data. 2:17 Recall that we're following a model view controller, or 2:20 MVC design pattern, where the model 2:23 is classes that represent the data we're getting from the the Dark Sky API. 2:25 Our project currently has one class. 2:30 We go to app Java. 2:32 And here, our model class is current weather. 2:34 We'll be getting more data, and we'll add another class. 2:38 Since we're gonna have a few models, let's make a new subpackage in our project. 2:41 We'll call it weather, to store our model classes. 2:46 I'm making refactored current weather into our new package. 2:52 Let's create a new class to hold the data for each hour. 3:05 Then, we can create an array of these 3:08 hour items to hold the whole hourly forecast array. 3:11 So we can make a new hour class. 3:14 I always have trouble naming classes, but we can always refactor later on, 3:21 if needed. 3:25 So now for our class variables, based on what we're using from 3:29 our hourly forecast object, we'll need a time, private long time. 3:34 Recall that the time value we are getting in from dark sky, is a Unix time value. 3:40 We'll need our summary, which is a string. 3:46 We'll need our temperature, which was a double value. 3:51 And we'll need our icon, which was another string. 3:57 We're going to need one additional piece of data later on, too. 4:03 For convenience, let's add it now, so we don't forget, or get stuck down the road. 4:07 That piece is the timezone, so 4:12 that we will be able to display the hour appropriately. 4:14 And we'll definitely need our getters and setters for these. 4:23 So let's let Android Studio generate those for us! 4:26 Code > Generate. 4:32 Getters and Setters, we want all of them. 4:34 Now we have two different model classes, current weather and hour. 4:39 But, we need a way to group them together. 4:43 We don't yet have a raise to hold the hourly forecast. 4:45 Our solution, is to again model our java classes after the data in the API. 4:49 We're getting data as a response from the Dark Sky server, and 4:55 it's all bundled together in one big JSONObject. 4:58 Let's create our own object to bundle up our model classes. 5:02 So Weather > New > Class. 5:07 We'll call it Forecast, and 5:11 it will have a current weather object and an array of hour items. 5:13 Call it Forecast. 5:17 So inside here, We want a private CurrentWeather, 5:22 we'll call it CurrentWeather. 5:28 We want an array of hour objects, we'll call it hourlyForecast, 5:34 And generate our Getters and Setters. 5:43 Now that we're in here, I don't much like the name CurrentWeather anymore. 5:50 Now that it's all part of this forecast object. 5:54 Let's refactor that class name to just be current. 5:57 Refactor, rename, we will call 6:00 it Current, and do the refactor. 6:05 We want to select all of them, and hit OK. 6:13 All right, our models are looking great. 6:23 Now that we have a separate package for our models, let's create a new subpackage 6:25 called UI for these other classes, and move them into it. 6:29 New > Package > UI. 6:34 I'll move our UI elements into our UI package. 6:37 Sometimes, when we move activities from one package to another, 6:44 it can cause an error inside the manifest file. 6:48 Let's check in there and take a look. 6:51 Sometimes, the Android name attribute for each activity element, isn't updated. 6:57 It should be fine like it is in here, but if your app crashes after a refactoring 7:03 package for activities, you may need to track down the error inside here. 7:08 Let's take a quick break, and tackle populating the daily weather forecast. 7:13
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