Question

我正在创建一个应用程序以从Web服务获取Json数据并将其绑定到条形图。

我不知道该怎么做。我正在使用MPAndroid库来制作图表。

帮我绑定JSON数据中的条形图数据。

网络服务：

[
  {
    "NAME": "601 GRIETA EN CUERPO",
    "PERCENTAGE": "46"
  },
  {
    "NAME": "77 ENFRIAMIENTO O DUNTING",
    "PERCENTAGE": "18"
  },
  {
    "NAME": "78 PRECALENTAMIENTO",
    "PERCENTAGE": "18"
  },
  {
    "NAME": "209 MAL MANEJO",
    "PERCENTAGE": "9"
  },
  {
    "NAME": "92 FUGA DE MANOMETRO",
    "PERCENTAGE": "9"
  }
]

BARCHART。的java

package com.example.saravanakumars.chart;

/**
 * Created by saravanakumars on 9/18/2017.
 */

import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.ContextMenu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;
import android.widget.Toast;

import com.github.mikephil.charting.charts.BarChart;
import com.github.mikephil.charting.data.BarData;
import com.github.mikephil.charting.data.BarDataSet;
import com.github.mikephil.charting.data.BarEntry;
import com.github.mikephil.charting.utils.ColorTemplate;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.util.ArrayList;
import java.util.HashMap;

public class barchart extends AppCompatActivity  {

    BarChart chart ;
    ArrayList<BarEntry> BARENTRY ;
    ArrayList<String> BarEntryLabels ;
    BarDataSet Bardataset ;
    BarData BARDATA ;

    private String TAG = MainActivity.class.getSimpleName();

    private ProgressDialog pDialog;
    private ListView lv;
    private static String url = "http://113.193.30.155/MobileService/MobileService.asmx/GetSampleData";

    ArrayList<HashMap<String, String>> contactList;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.bar_chart);


        contactList = new ArrayList<>();

        lv = (ListView) findViewById(R.id.list);

        new GetContacts().execute();

//        bar chart

        chart = (BarChart) findViewById(R.id.barchart);
        BARENTRY = new ArrayList<>();
        BarEntryLabels = new ArrayList<String>();
        AddValuesToBARENTRY();
        AddValuesToBarEntryLabels();
        Bardataset = new BarDataSet(BARENTRY, "Projects");
        BARDATA = new BarData(BarEntryLabels, Bardataset);
        Bardataset.setColors(ColorTemplate.COLORFUL_COLORS);
        chart.setData(BARDATA);
        chart.animateY(3000);
     }
        });
//        registerForContextMenu( txt1 );
    }

 @Override
    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo)
    {
        super.onCreateContextMenu(menu, v, menuInfo);
        MenuInflater inflater = getMenuInflater();
        menu.setHeaderTitle("Select The Action");
        inflater.inflate( R.menu.popup_menu,menu );
    }
    @Override
    public boolean onContextItemSelected(MenuItem item){
        switch (item.getItemId()) {
            case R.id.one:
                Toast.makeText(barchart.this,"You Clicked : " + item.getTitle(),Toast.LENGTH_SHORT).show();
                break;
            case R.id.two:
                Toast.makeText(barchart.this,"You Clicked : " + item.getTitle(),Toast.LENGTH_SHORT).show();
                break;

        }
        return true;
    }
    private class GetContacts extends AsyncTask<Void, Void, Void> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            // Showing progress dialog
            pDialog = new ProgressDialog(barchart.this);
            pDialog.setMessage("Please wait...");
            pDialog.setCancelable(false);
            pDialog.show();

        }

        @Override
        protected Void doInBackground(Void... arg0) {
            HttpHandler sh = new HttpHandler();

            // Making a request to url and getting response
            String jsonStr = sh.makeServiceCall(url);

            Log.e(TAG, "Response from url: " + jsonStr);

            if (jsonStr != null) {
                try {

                    JSONArray array = new JSONArray(jsonStr);
                    for (int i = 0; i < array.length(); i++) {
                        JSONObject object = (JSONObject) array.get(i);
                        String NAME = object.getString("NAME");
                        String PERCENTAGE = object.getString("PERCENTAGE");
                        int minqty = Integer.parseInt(object.getString("PERCENTAGE"));
                        HashMap<String, String> contact = new HashMap<>();

                        BARENTRY.add(minqty);
                        contact.put("NAME", NAME);
                        contact.put("PERCENTAGE", PERCENTAGE);

                        // adding contact to contact list
                        contactList.add(contact);
                    }

                } catch (final JSONException e) {
                    Log.e(TAG, "Json parsing error: " + e.getMessage());
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            Toast.makeText(getApplicationContext(),
                                    "Json parsing error: " + e.getMessage(),
                                    Toast.LENGTH_LONG)
                                    .show();
                        }
                    });

                }
            } else {
                Log.e(TAG, "Couldn't get json from server.");
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        Toast.makeText(getApplicationContext(),
                                "Couldn't get json from server. Check LogCat for possible errors!",
                                Toast.LENGTH_LONG)
                                .show();
                    }
                });

            }

            return null;
        }

        @Override
        protected void onPostExecute(Void result) {
            super.onPostExecute(result);
            // Dismiss the progress dialog
            if (pDialog.isShowing())
                pDialog.dismiss();
            /**
        }

    }

}

Answer 1

使用gson从你的jSON创建对象：

YourModelClass yourModelClassObject = gson.fromJson(args[0].toString(), YourModelClass.class);

然后获取您的arrayList并将其提供给图表数据集使用以下链接从您的JSON生成pojo http://www.jsonschema2pojo.org/

Answer 2

作为替代方案，您可以使用wannacharts.com ..是一种api like服务，您可以在api的url中发布Json，响应是带有图表base64图像的json（{ {3}}），或带有图表的png文件的url。

好的部分是你不必使用任何外部库！

是免费的，但之前您必须在图表设计器中注册并预先设置图表。

以下是how to decode base64 image in android

将Json数据绑定到条形图

2 个答案: