Reading JSON from a Server_Assignment Solution

Assignment: Reading JSON from a Server
Overview In this assignment you will write an app to read a JSON file from a remote server and display the file contents in an easily readable and labeled manner. The JSON file follows the format shown here: { "clients": [ {"name": "Jim Lincoln", "profession": "Musician", "dob": "Oct. 2, 1945", "children":[ "Jane", "Peter" ] }, { "name": "Mary Jones", "profession": "Programmer", "dob": "April 2, 1980", "children":[ "Joe", "Sue" ] }, // more entries....
{ "name": "Anne Sprague", "profession": "Urban Planner", "dob": "January 12, 1970", "children":[ ] } ] }
2/22/2015 Advanced Course 1 - Assignment
http://www.seasite.niu.edu/csci628/Assignments/Spring2015/A2_Read_JSON.htm 2/3
The JSON file can be found at "http://www.seasite.niu.edu/cs680Android/JSON/Client_list_json.txt" and will be served by that site's web server, so it can be read via an http Get command. (It can be displayed using a web browser if you are curious to see the exact whole file.)  Since the Get command will result in a data stream that will be read by your program's code, and since these read calls will block if the next chunk of data from the server is delayed, your code to retrieve the JSON data should execute in a separate Thread of execution. Note that this file consists of a named array of (1 - many) objects (clients). In this case each object consists of information about one person, including a list/array of that person's children (0 - many). Incidentally, http://www.jsonlint.com has a nice online JSON syntax checker if you need to create your own JSON file and need to find out if there are any syntax errors that would trip up your parsing code. Platform Implementation Notes Android Create a simple app screen with text instructing the user to press the Go button to download the file.  This text should also inform the user that the app's output will be to the LogCat console and app screen.  Obviously, the app should include a functioning Go button. Do not spend time on an elegant screen display of the JSON information - just echo it to LogCat and also create a big multiline String and display it in a TextView.  Each person in the file should be displayed as follows: Name: Mary Jones Profession: Programmer DOB: April 2, 1980 Children: Joe, Sue ---------------------------Extend AsynchTask to do the JSON file read in a separate Thread.  Implement this as an inner class so it will have access to the TextView display widget.  Write doInBackground() to set up the http connection, read the file (building a StringBuffer object, creating a String from it, and then returning a JSONObject created from that String. onPostExecute() (or a called custom method in this class) will then parse the JSONObject returned by doInBackground() and display the file contents on LogCat and screen. Your code should write informative error messages to LogCat in the event that there is a parsing error on the JSON file or other error condition. iOS Parse JSON-formatted data and display them in two views -- i.e. using the master-detail iOS application template. The first view contains a UITableview. Each cell of the table should contain a name and profession. Clicking on a table cell should take the user to the detail view. The title of the detail view should reflect the selected name and the detail view must contain a profession, date of birth and children (if any). An excellent code example of working with JSON in iOS 5 and up can be found here: http://www.raywenderlich.com/5492/working-with-json-in-ios-5 Windows Phone Use a WebClient to connect to the Uri identified above. Fetch the json file using DownloadStringAsync
2/22/2015 Advanced Course 1 - Assignment
http://www.seasite.niu.edu/csci628/Assignments/Spring2015/A2_Read_JSON.htm 3/3
and attach an event handler to the DownloadStringCompleted event. In the DownloadStringCompleted event handler, put the fetched json string into an array of byte and then create a MemorySream from that byte array. Now create an instance of DataContractJsonSerializer and use it to ReadObject() from the stream. The object that is read should contain a List<Client where a Client object contains name, profession, dob, and a List<string for the children. Assign the List<Client to the page's DataContext and put a ListBox in the UI that uses data binding to display the pieces of information in each client object.