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Introducing JSONArray4:45 with Ken Alger
JSONArray allows for working with more complex JSON data than JSONObject in Android.
So far, we've been using the JSON object class to work with our JSON data. 0:00 Now, we're going to look at another important class we're working with JSON in 0:04 Android development, JSON array. 0:08 Recall from previous explorations that JSON data is stored in two formats. 0:11 A JSON object, which is a collection of key-value pairs. 0:16 And an ordered-list of JSON objects, which we can think of as an array. 0:20 JSON object takes care of regular objects. 0:26 An JSON array is basically an array that can hold JSON objects, 0:30 or even other JSON arrays. 0:35 Recall that arrays in JSON are indicated with square brackets. 0:38 Here in the hourly session, we have an array called data. 0:42 Each JSON object inside the array is surrounded with curly braces. 0:48 We'll access this data array in code and then store object 0:58 in here as an array item using our new hour class. 1:04 Lets go back to Android Studio. 1:10 Let's take another look at our new parseForecastData method. 1:14 Our Forecast class has that array to fill, an hourly forecast. 1:18 Let's create a new method to fill it following the format we used to fill 1:22 the current weather data. 1:26 We can write the code we want and then autogenerate the new method declaration. 1:28 Inside parseForecastData, we can add our new statement here. 1:32 We want forecast.setHourlyForecast, and 1:40 our new method we'll call getHourlyForecast. 1:45 And we'll pass in jsonData as well. 1:51 And we can use the quick fix to generate our method. 1:54 So inside getHourlyForecast, 2:01 we want to start just like we do in getCurrentDetails. 2:03 We'll get a JSONObject. 2:08 We'll call it forecast. 2:11 And set new JSONObject from our jsonData. 2:16 We want to grab the timezone, just like we do in getCurrentDetails, as well. 2:22 Timezone. 2:29 It's gonna be forecast.getString. 2:33 And the timezone was timezone in all lower case 2:38 And we have that unhandled JSON exception error again. 2:45 We can do the quick fix to add the exception to our method signature. 2:49 All right, now how is that JSON data structured again? 2:55 Let's take another look. 3:00 Hm, it looks like we need this hourly JSON object from the data. 3:06 Okay, we can do that. 3:12 Let's create a new JSON object, we'll call it hourly. 3:17 And then set it from the forecast object using the getJSONObject method. 3:20 JSONObject hourly forecast.getJSONObject. 3:27 We just saw in the data that key we need is called hourly, 3:35 in all lower case, hourly. 3:39 Now we're ready to drill down and get our data array. 3:45 Let's take one more look at our JSON data, just to make sure. 3:48 The hourly object has an array named data. 3:55 We can use this name as the key to get the array, just like we did for 3:59 the hourly object. 4:03 JSONArray, We'll call it data. 4:08 Hourly.getJSONArray. 4:15 And it's data. 4:19 Now we have an array of JSONObjects, great work! 4:23 We still want an array of our objects, though. 4:26 How should we go about converting them? 4:30 Why don't you give it a try yourself and 4:32 then come back in the next video to see how I tackled it. 4:34 Here's a hint, 4:38 you can access the length of JSONArray object by using a method called blank. 4:39
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