Introducing JSONObject

Android provides some convenient ways to handle JSON data. 0:00 Making it easy to work with. 0:04 With our app connected to and receiving weather data in a JSON format. 0:06 Let's take a look at how we can leverage the tools provided by Android to parse 0:10 the weather data to get the information our app will use. 0:14 We have our new data model object, CurrentWeather. 0:18 Let's put it to use in main activity. 0:21 So under our tag here, let's create a new, private, 0:25 CurrentWeather object, and we'll call it currentWeather. 0:29 Now, we'll want to set this, once we have a successful response. 0:34 So we scroll down to our onResponse, and 0:38 inside our if statement here where our response is successful. 0:41 Let's set currentWeather. 0:46 And we'll set it to a new method that we'll define here in a moment. 0:49 We'll call it getCurrentDetails. 0:55 We'll want to pass in JSON data. 0:58 We can use the response.body that we have up here in our tag. 1:01 But let's actually refactor that into a variable, and use it in both places. 1:12 String.jsonData. 1:20 Now we can pass in jsonData. 1:26 Okay, now let's use the quick fix provided by Android Studio we put there. 1:42 Alt + Enter, Create method. 1:47 And again we want that inactivity not in our onCreate anonymous callback. 1:51 Next, we're going to work with a special class called JSONObject. 2:01 This class is able to hold any object represented in JSON format, and 2:05 provides a few different methods to access the properties inside the JSON data. 2:10 The JSONObject class has a constructor that lets us pass in a string 2:15 of jsonData to create the new JSONObject. 2:19 Fortunately, that's just what we have as a parameter. 2:23 Let's create a new JSONObject inside our new method. 2:27 JSONObject, plot forecast cuz that's what we're getting back. 2:31 We see that we have an error here. 2:41 We hover over it. 2:43 We see that it is an unhandled exception. 2:44 This is similar to the IOException we previously seen. 2:48 But this is a JSONException. 2:51 Just like we've done before, we can use the quick fix to add a dry catch. 2:54 Now, while this works, this isn't ideal. 2:59 It would be better if we could have the exception handle, or 3:03 the getCurrentDetails method is called. 3:05 Up here where the IOException is being caught. 3:10 It would be great if we could get this new exception to bubble up, and 3:13 be caught up here. 3:16 We can do that with a throws keyword. 3:18 Back here in getCurrentDetails, let's undo our try/catch block, 3:20 and after our method signature before the curly brace, we wanna type throws. 3:27 And then we need the specific type of exception. 3:34 In this case, it is a JSONException This 3:37 moves the responsibility of exception handling from this line here in 3:42 getCurrentDetails to up here where the method is called. 3:47 We see now in onResponse where getCurrentDetails is called, 3:52 it has an error. 3:56 Since we're already inside a try block, we can catch the JSONException down here. 3:57 We'll catch the JSONException. 4:03 And we'll add a log statement for it. 4:13 Now our code is a bit more organized since our exceptions are all being handled in 4:23 one place. 4:28 With that exception handled, we can continue to set our JSON object. 4:29 Let's take a quick look at the Android documentation on JSON object. 4:33 Let's see what types of data we can get. 4:42 We see that this class has several methods that allow to get different types of data. 4:46 Strings, ints, booleans, JSON arrays. 4:57 Even other JSON objects. 5:01 We'll see some of these methods used in other projects, as well. 5:03 Let's take another look at our data as a guide for 5:07 how we should parse our JSON object. 5:09 The JSON object forecast that we just created in our code 5:11 corresponds to this root object up here. 5:16 Remember our root object starts with a first opening brace. 5:21 We're passing latitude and longitude in as parameters to the API call. 5:25 So we don't need to worry about those. 5:29 Let's use this timezone field as an example to start. 5:31 timezone in all lower case is the key we want to get. 5:35 The value is enclosed in double quotes. 5:39 That tells us that it is a string value. 5:42 Let's go back to our getCurrentDetails method. 5:46 So we can access this timezone, and write it to the log. 5:52 So String_ timezone. 5:57 We're gonna get forecast.getString. 6:02 We need to pass in the key we want. 6:07 We say that it was timezone in all lower case. 6:09 Then we want to log that. 6:16 So Log.i, TAG say From JSON 6:20 plus our timezone. 6:26 Cool, we should test this out just to make sure we are, 6:32 in fact, getting what we're expecting. 6:36 This is important, especially when trying to parse through complex data. 6:38 Building things one step at a time, and 6:42 verifying them along the way is a great habit to get into. 6:44 Otherwise, you can end up with a lot of code that can be broken in multiple 6:48 places. 6:52 Now, before we run it, 6:53 we have another area here because we aren't returning anything. 6:55 Let's just return null for now. 6:58 Run our app. 7:06 And checking here in the Logcat. 7:12 Here's our parsed data from JSON, America/Los_Angeles. 7:17 It's working! 7:20 That's great! 7:21 Let's take a quick break, and 7:22 we'll get our current weather all set up when we come back. 7:23