Mobile Programming - Android

1. API-Application
Programming
Interface
TK2323 Mobile Programming
Sem 1 2017/2018
Lam Meng Chun
lammc@ukm.edu.my (G-02)

2. Outline
JSON
▹ Number
▹ String
▹ Boolean
▹ Object
▹ Array
API
▹ Concept
JSON in Android
2

3. JSON
3

4. 4 JSON
▹JSON (JavaScript Object Notation) is a lightweight data-
interchange format.
▸Data is in name/value pairs
▸Data is separated by commas ,
▸Curly braces hold objects { }
▸Square brackets hold arrays [ ]
4

5. 5 JSON
▹ http://lrgs.ftsm.ukm.my/phpmyadmin/index.php
▹ http://lrgs.ftsm.ukm.my/phpmyadmin/ftp
5

6. 6 Name/Value pairs
Name/Key Value:
{ “Matrix No” : “A111111” }

7. 7 JSON
▹JSON values can be:
7
Type Example
Number 12 , 12.5
String “Alan”
Boolean True, False
Array “Car_Brands” : [ “Honda”, “Mercedes” , “Subaru” ]
Object “User”: {“Matrix_No”: ”A111111”,
“Name”: ”Alan”}

8. 8 Name/Value pairs
Name Value:
{ “Matrix No” : “A111111” }
{ “Fees” : 500.00}
String Matrix No = “A111111”;
float Fees = 500.00;

9. 9 JSON
▹A number (integer or
floating point)
▹A string (in double
quotes)
▹A Boolean (true or
false)
9
{
“Burger Price“ : 20.0
}
{
“Burger Name“ : “TK2323 Burger”
}
{
“Delicious“ : false
}

10. 10 JSON
▹An array (in square brackets) ▹An object (in curly braces)
10
{
“Courses” : [ “TK2323”, “TR2312”,
“TP4345”]
}
“Member”: {
"name":“Ali",
"age":30,
“Matrix No":”A111111”
}
{
“Prices” : [ 10, 20, 15 ,88]
}

11. 11 JSON: Nested
▹List of objects inside an array
▹A “books” object contains array of “language”, “edition”
and “lastName” object
11

12. 12 JSON

13. API
13

14. 14
API - Concept
Select Club_ID, Club_name
From Clubs (Web)
Select Club_ID, Club_name
From Clubs (Android)…
14
Clubs
Club_ID Club_Name
ClubSIG01 Robotic (ARViS)
ClubSIG02 Interactive Multimedia (iMec)
ClubSIG03 Mobile Apps Development (MAD
Club)

15. 15
API - Concept
Select Club_ID, Club_name
From Clubs (API)
15
Clubs
Club_ID Club_Name
ClubSIG01 Robotic (ARViS)
ClubSIG02 Interactive Multimedia (iMec)
ClubSIG03 Mobile Apps Development (MAD
Club)

16. 16
API –
Concept
Request and
Response
▹http://samples.openw
eathermap.org/data/2.5
/forecast?q=M%C3%BC
nchen,DE&appid=b1b15
e88fa797225412429c1c5
0c122a1
▹www.google.com

17. 17 API - Concept
Endpoint
▹ Basically is an URL
▹ Description
Method
▹ POST (Create)
▹ GET (Read)
▹ PUT
(Update/Relace)
▹ DELETE (Delete)
PARAMETER
▹ Key
▹ Data Type
▹ Section
(In URL/ in Body)
▹ Required or not
▹http://petstore.swagger.io/
▹http://petstore.swagger.io/v2/store/inventory

18. 18 Example

19. 19

20. 20 Postman - Example
▹How to make request
▸End Point
▸Method
▸Data

21. 21
Postman –
End Point
and Method

22. 22
Postman –
Data in URL

23. 23
Postman –
Data in Body

24. 24
API – Method and status
code
HTTP Verb CRUD
Entire Collection (e.g.
/customers)
Specific Item (e.g.
/customers/{id})
POST Create 201 (Created), 'Location' header
with link to /customers/{id}
containing new ID.
404 (Not Found), 409
(Conflict) if resource already
exists..
GET Read 200 (OK), list of customers. Use
pagination, sorting and filtering to
navigate big lists.
200 (OK), single customer.
404 (Not Found), if ID not
found or invalid.
PUT Update/Replace 405 (Method Not Allowed), unless
you want to update/replace every
resource in the entire collection.
200 (OK) or 204 (No
Content). 404 (Not Found), if
ID not found or invalid.
DELETE Delete 405 (Method Not Allowed), unless
you want to delete the whole
collection—not often desirable.
200 (OK). 404 (Not Found), if
ID not found or invalid.

25. 25 API – Server side
▹TTTP2543 Web Programming
▹Possible server side technology (microframework)
▸PhP (Lumen, Wave Framework, Slim…)
▸Python (Flask, FALCON,…)
▸Ruby on Rails

26. 26 Resources
▹http://petstore.swagger.io/
▹https://jsonlint.com
▹https://jsonformatter.curiousconcept.com/
▹https://www.getpostman.com/
▹HTTP response status codes: https://developer.mozilla.org/en-
US/docs/Web/HTTP/Status

27. Request from
Android
27

28. 28
Request from Android -
Libraries
▹OkHttp
▹Retrofit
▹Volley

29. 29 Volley

30. 30 Volley - Request
▹4 Parameters needed
▸Method (GET, PUT, POST, DELETE)
▸URL
▸Response Listener
▸Error Listerner
▹Data to be sent

31. Request from
Android – No data
sent
31

32. 32 Volley - Request
public static final String JSON_VIEW_MEMBER_URL = "http://lrgs.ftsm.ukm.my/users/lam/view_member.php";
StringRequest myReq = new StringRequest(
Request.Method.GET,
JSON_VIEW_MEMBER_URL,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
}
},
new ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
});

33. 33
Volley –
Request (No
data)
public void onResponse(String response) {
try {
JSONObject jsonResponse = new JSONObject(response);
JSONArray jsonArray = jsonResponse.getJSONArray("result");
Member member;
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jo = jsonArray.getJSONObject(i);
String matrix = jo.getString("fld_matrix_no");
String name = jo.getString("fld_member_name");
String club = jo.getString("fld_club_id");
String status = jo.getString("fld_status");
member = new Member(id, matrix, name, club, status);
member_list.add(matrix + ", " + name + ", " + club + ", " + status);
member_list_object.add(member);
}
memberAdapter = new ArrayAdapter<String>(getApplicationContext(),
android.R.layout.simple_list_item_1, member_list);
lv_member.setAdapter(memberAdapter);
} catch (JSONException e) {
e.printStackTrace();
}
}

34. 34
Volley -
Request
new ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
});
RequestQueue queue = Volley.newRequestQueue(this);
queue.add(myReq);

35. 35

36. 36
▹JSONArray
▸A dense indexed sequence of
values.
▹JSONObject
▹A modifiable set of
name/value mappings.

37. Request from
Android – Data in
Body
37

38. 38
Volley – Request (Data in
body)
public static final String JSON_ADD_MEMBER_URL = "http://lrgs.ftsm.ukm.my/users/lam/add_member.php";
StringRequest myReq = new StringRequest(Request.Method.POST, JSON_ADD_MEMBER_URL, new Response.Listener<String>() {
@Override
public void onResponse(String response) {
Log.d("Response", response);
adapter.clear();
populateMemberRequest();
}
}, new ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Log.d("Error.Response", error.toString());
}
}) {
@Override
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<String, String>();
params.put("matrix", id);
params.put("name", name);
params.put("club_id", club_id);
params.put("status", status);
return params;
}
};
RequestQueue queue = Volley.newRequestQueue(this);
queue.add(myReq);
}

39. 39
Volley – Request (Data in
body)
public static final String JSON_ADD_MEMBER_URL =
"http://lrgs.ftsm.ukm.my/users/lam/add_member.php";
StringRequest myReq = new StringRequest(Request.Method.POST, JSON_ADD_MEMBER_URL, new
Response.Listener<String>() {
@Override
public void onResponse(String response) {
Log.d("Response", response);
adapter.clear();
populateMemberRequest();
}
}, new ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Log.d("Error.Response", error.toString());
}
})
{
Data is here
};
RequestQueue queue = Volley.newRequestQueue(this);
queue.add(myReq);
}

40. 40
Volley – Request (Data in
body)
public static final String JSON_ADD_MEMBER_URL =
"http://lrgs.ftsm.ukm.my/users/lam/add_member.php";
StringRequest myReq = new StringRequest(Request.Method.POST, JSON_ADD_MEMBER_URL, new
Response.Listener<String>() {
@Override
public void onResponse(String response) {
}
}, new ErrorListener() {
})
{
@Override
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<String, String>();
params.put("matrix", id);
params.put("name", name);
params.put("club_id", club_id);
params.put("status", status);
return params;
}
};
RequestQueue queue = Volley.newRequestQueue(this);
queue.add(myReq);

41. Request from
Android – Data in
URL
41

42. 42
Volley – Request (Data in
URL)
Response.Listener<String> responseListener = new Response.Listener<String>() {
@Override
public void onResponse(String response) {
try {
JSONObject jsonResponse = new JSONObject(response);
boolean success = jsonResponse.getBoolean("success");
if (success) { } else { }
} catch (JSONException e) {
e.printStackTrace();
}
}
};
DeleteMemberRequest deleteMemberRequest = new DeleteMemberRequest(matrix_no,
responseListener);
RequestQueue queue = Volley.newRequestQueue(getApplicationContext());
queue.add(deleteMemberRequest);
}
}

43. 43
Volley – Request (Data in
URL)
public class DeleteMemberRequest extends StringRequest {
/* private Map<String, String> params; */
public DeleteMemberRequest(String matrix_no, Response.Listener<String> listener)
{
super(Method.DELETE, JSON_DELETE_MEMBER_URL + matrix_no, listener, null);
/* params = new HashMap<>();
params.put("matrix_no", matrix_no);*/
}