How to use the Facebook Graph Api Cursor-based Pagination

Question

I didn\'t find any help on this topic. The Docs say

Cursor-based pagination is the most efficient method of paging and should always be used where possibl

Answer 1

I use this code:

final String[] afterString = {""}; 
final Boolean[] noData = {true};
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);

do{
   GraphRequest request = GraphRequest.newGraphPathRequest(
            AccessToken.getCurrentAccessToken(),
            "/me/likes",
            new GraphRequest.Callback() {
                @Override
                public void onCompleted(GraphResponse response) {
                    // Insert your code here
                    JSONObject jsonObject = response.getJSONObject();
                    try{
                        if(jsonObject.length() > 1) {

                            JSONObject jsonFacebook = (JSONObject) new JSONTokener(jsonObject.toString()).nextValue();
                            JSONObject likes_paging = (JSONObject) new JSONTokener(jsonFacebook.getJSONObject("paging").toString()).nextValue();

                            ArrayList<String> likes = new ArrayList<String>();
                            for (int i = 0; i < jsonFacebook.getJSONArray("data").length(); i++) {
                                likes.add(jsonFacebook.getJSONArray("data").getJSONObject(i).getString("name"));
                            }
                            afterString[0] = (String) likes_paging.getJSONObject("cursors").get("after");

                        }else{
                            noData[0] = false;
                        }
                    } catch (JSONException e) {
                        e.printStackTrace();
                    }
                }
            });

    Bundle parameters = new Bundle();
    parameters.putString("pretty", "0");
    parameters.putString("limit", "100");
    parameters.putString("after", afterString[0]);
    request.setParameters(parameters);
    request.executeAndWait();
}while(noData[0] == true);

Answer 2

What I did in my project is basically doing the first call in onSearchClicked() and getting result in onCompleted() callback in ViewModel. If nextRequest is null, I return the list of results back to my fragment, if not, I do the next call, until the end is reached (nextRequest == null). Then, the accumulated list is returned to the fragment.

class SearchViewModel() : GraphRequest.Callback {

    private var allPlaces = arrayListOf<FacebookPlace>()

    fun onSearchClicked(location: Location) {
      val request = GraphRequest.newGraphPathRequest(accessToken, "/search", this)
      request.parameters = parameters
      request.executeAsync()
    }

    override fun onCompleted(response: GraphResponse?) {
      if (response != null) {
        allPlaces.addAll(response.data)

        val nextRequest = response.getRequestForPagedResults(GraphResponse.PagingDirection.NEXT)
        if (nextRequest == null) {
            uiEvent.value = ShowPlaces(allPlaces)
        } else {
            nextRequest.callback = this
            nextRequest.executeAsync()
        }
    } else {
        Log.e(TAG, "Search response is null.")
    }
}

Answer 3

Though it's true that you should use GraphResponse.getRequestForPagedResults(), you can't use executeAndWait() unless you run it in a different thread.

You can make it even easier using executeAsync().

To get the first set of results:

    new GraphRequest(AccessToken.getCurrentAccessToken(),
            "/" + facebookID + "/invitable_friends",
            null,
            HttpMethod.GET,
            new GraphRequest.Callback() {
                public void onCompleted(GraphResponse response) {
                    //your code

                    //save the last GraphResponse you received
                    lastGraphResponse = response;
                }
            }
    ).executeAsync();

Use that lastGraphResponse to get the next set of results:

    GraphRequest nextResultsRequests = lastGraphResponse.getRequestForPagedResults(GraphResponse.PagingDirection.NEXT);
    if (nextResultsRequests != null) {
        nextResultsRequests.setCallback(new GraphRequest.Callback() {
            @Override
            public void onCompleted(GraphResponse response) {
                //your code

                //save the last GraphResponse you received
                lastGraphResponse = response;
            }
        });
        nextResultsRequests.executeAsync();
    }

You can merge all that in a single method!

Answer 4

I figured out a good way to traverse through facebook graph api pages using cursor pagination

    final String[] afterString = {""};  // will contain the next page cursor
    final Boolean[] noData = {false};   // stop when there is no after cursor 
    do {
        Bundle params = new Bundle();
        params.putString("after", afterString[0]);
        new GraphRequest(
                accessToken,
                personId + "/likes",
                params,
                HttpMethod.GET,
                new GraphRequest.Callback() {
                    @Override
                    public void onCompleted(GraphResponse graphResponse) {
                        JSONObject jsonObject = graphResponse.getJSONObject(); 
                        try {
                            JSONArray jsonArray = jsonObject.getJSONArray("data");

                            //  your code 


                            if(!jsonObject.isNull("paging")) {
                                JSONObject paging = jsonObject.getJSONObject("paging");
                                JSONObject cursors = paging.getJSONObject("cursors");
                                if (!cursors.isNull("after"))
                                    afterString[0] = cursors.getString("after");
                                else
                                    noData[0] = true;
                            }
                            else
                                noData[0] = true;
                        } catch (JSONException e) {
                            e.printStackTrace(); 
                        }
                    }
                }
        ).executeAndWait();
    }
    while(!noData[0] == true);

Answer 5

Do not reinvent the wheel.

GraphResponse class already has a convenient method for paging. GraphResponse.getRequestForPagedResults() returns GraphRequest object, and you can use that object for paging.

Also I found code snippet from facebook-android-sdk's unit test code.

GraphRequest nextRequest = response.getRequestForPagedResults(GraphResponse.PagingDirection.NEXT);
nextRequest.setCallback(request.getCallback());
response = nextRequest.executeAndWait();