Android MPAndroidChart getting partial Pie chart : retrieving data from server using volley library

Question

I am using MPAndroidChart library for pie chart in my android application, using mysql server data. I used volley library to retrieve the data from server.

I can able to retrieve data json successfully:

com.example.bharat.plantnow D/ChartActivity﹕ Location Response: [{"treecondition":"Balanced","Count":"2"},{"treecondition":"Dieseased","Count":"1"},{"treecondition":"Healthy","Count":"4"},{"treecondition":"Imbalance","Count":"2"},{"treecondition":"Transplanted","Count":"1"}]

But In pie chart , I am getting only last value i.e "Transplated" with Count "1", remaining not able to display. Pl help me where I am getting wrong in CODE.

private boolean addData(){
       String tag_string_req = "req_location";

     showDialog();
    StringRequest strReq = new StringRequest(Request.Method.POST,
            AppConfig.URL_PIECHART, new Response.Listener<String>() {

        @Override
        public void onResponse(String response) {
            Log.d(TAG, "Location Response: " + response.toString());
            hideDialog();
            try {
                JSONArray jTreeList = new JSONArray(response);
                // boolean error = jObj.getBoolean("error");


                // Check for error node in json
                for (int i = 0; i < jTreeList.length(); i++) {

                    JSONObject location = jTreeList.getJSONObject(i);

                    String treecondition = location.getString("treecondition");
                    Integer count = location.getInt("Count");

                    ArrayList<Entry> yVals1 = new ArrayList<Entry>();
                       for (int j = 0; j < count; j++)
                        yVals1.add(new Entry((count), j));

                    ArrayList<String> xVals = new ArrayList<String>();
                    for(int j = 0; j < treecondition.length();j++)
                    xVals.add(treecondition);

                    //create pie data set

                    PieDataSet dataSet = new PieDataSet(yVals1,"First pie chart");

                    dataSet.setSliceSpace(3);
                    dataSet.setSelectionShift(5);

                    //add many colours

                    ArrayList<Integer> colors = new ArrayList<Integer>();

                    for (int c : ColorTemplate.VORDIPLOM_COLORS)
                        colors.add(c);

                    for (int c : ColorTemplate.JOYFUL_COLORS)
                        colors.add(c);

                    for (int c : ColorTemplate.COLORFUL_COLORS)
                        colors.add(c);

                    for (int c : ColorTemplate.LIBERTY_COLORS)
                        colors.add(c);

                    for (int c : ColorTemplate.PASTEL_COLORS)
                        colors.add(c);

                    colors.add(ColorTemplate.getHoloBlue());
                    dataSet.setColors(colors);


                    //instantiate pie data object now

                    PieData data = new PieData(xVals,dataSet);
                    data.setValueFormatter(new PercentFormatter());
                    data.setValueTextSize(11f);
                    data.setValueTextColor(Color.GRAY);


                    mChart.setData(data);

                    //undo all highlight

                    mChart.highlightValue(null);

                    //update pie chart

                    mChart.invalidate();



                }

            } catch (JSONException e) {
                // JSON error
                e.printStackTrace();
                Toast.makeText(getApplicationContext(), "Json error: " + e.getMessage(), Toast.LENGTH_LONG).show();

            }

        }
    }, new Response.ErrorListener() {

        @Override
        public void onErrorResponse(VolleyError error) {
            Log.e(TAG, "Login Error: " + error.getMessage());
            Toast.makeText(getApplicationContext(),
                    error.getMessage(), Toast.LENGTH_LONG).show();

            hideDialog();
        }
    });

    // Adding request to request queue
    AppController.getInstance().addToRequestQueue(strReq, tag_string_req);

    return false;





}

Answer 1

I am 99% sure your code that I am showing below does not do what you expect it to do:

  String treecondition = location.getString("treecondition");
  Integer count = location.getInt("Count");

  ArrayList<Entry> yVals1 = new ArrayList<Entry>();

  for (int j = 0; j < count; j++)
      yVals1.add(new Entry((count), j));

  ArrayList<String> xVals = new ArrayList<String>();

  for(int j = 0; j < treecondition.length();j++)
       xVals.add(treecondition);

I'll evaluate what this code will do in terms of the PieChart:

• Your first for-loop has as many iterations as specified in the count variable. Then you add the count variable to an Entry. This will result in each slice having the same value and being equally sized, completely independent of your data.

• Your second for-loop has as many iterations as the String-variable treecondition has characters. Then you always add that same string to your x-values array in each iteration. If you for example have a String "Horse", this will result in an x-values array of length 5 containing the String "Horse" five times.

If that is not what you expect your code to do, then I suggest you check your for-loops again.

EDIT:

I get it now. The issue is that your "count" variable is 1. This means only one Entry will be added to the chart - and therefore you can see only one Entry.

Adding more x-values alone will not create any more slices on the PieChart since there is no more data for the slices.