Question

我正在尝试从网站中提取数据并在我的Android应用中显示图表。我哪里弄错了？它无法解析JSON。我经历了一些链接，但无法解决问题。

请说明我可以在这两个方面做些什么改变。

如何在视图[第126行]
我是否以正确的方式声明了ListView [第118行] 我在代码中标记了这些行。请参阅。提前致谢

我得到的错误被粘贴

JSON Parser: Error parsing data org.json.JSONException: Expected ':'
after n at character 5 of {n  "status": "ok",n  "name": "Transaction
Rate",n  "unit": "Transactions Per Second",n  "period": "minute",n 
"description": "The number of Bitcoin transactions added to the
mempool per second.",n  "values": [n    {n      "x": 1481383260,n     
"y": 3.060833333333333n    },n    {n      "x": 1481385240,n      "y":
3.0708333333333324n    },n    {n      "x": 1481387220,n      "y":

MainActivity.Java

package com.example.garima.bitcoingraph;

import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.w3c.dom.Text;

import android.app.Activity;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;

import java.util.List;

import garima.asynctask.library.JSONParser;

public class MainActivity extends AppCompatActivity {
    TextView status;
    TextView name;
    TextView unit;
    TextView period;
    TextView description;
    ListView value;

    Button Btngetdata;

    //URL to get JSON Array
    private static String url = "https://api.blockchain.info/charts/transactions-per-second?timespan=5weeks&rollingAverage=8hours&format=json";

    //JSON Node Names
    private static final String TAG_STATUS = "status";
    private static final String TAG_NAME = "name";
    private static final String TAG_UNIT = "unit";
    private static final String TAG_PERIOD = "period";
    private static final String TAG_DESCRIPTION="description";
    private static final String TAG_USER="user";
    private static final String TAG_VALUE="value";
    private static final String TAG = "MyActivity";
    JSONArray user = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);
        Btngetdata = (Button)findViewById(R.id.getdata);
        Btngetdata.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View view) {
                new JSONParse().execute();

            }
        });

    }

    private class JSONParse extends AsyncTask<String, String, JSONObject> {
        private ProgressDialog pDialog;
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            status = (TextView)findViewById(R.id.status);
            name = (TextView)findViewById(R.id.name);
            unit = (TextView)findViewById(R.id.unit);
            period=(TextView)findViewById(R.id.period);
            description=(TextView)findViewById(R.id.description);
            value=(ListView)findViewById(R.id.value);
            pDialog = new ProgressDialog(MainActivity.this);
            pDialog.setMessage("Getting Data ...");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(true);
            pDialog.show();

        }

        @Override
        protected JSONObject doInBackground(String... args) {
            JSONParser jParser = new JSONParser();

            // Getting JSON from URL
            JSONObject json = jParser.getJSONFromUrl(url);
            Log.i(TAG,"json found is"+json);
            return json;
        }

        @Override
        protected void onPostExecute(JSONObject json) {
            pDialog.dismiss();
            Log.i(TAG,"json is"+json);
            try {

                // Getting JSON Array<Discuss how to get values>
               user = json.getJSONArray(TAG_USER);
               JSONObject c = user.getJSONObject(0);

                // Storing  JSON item in a Variable
                String Status_Value = c.getString(TAG_STATUS);
                String Name_Value = c.getString(TAG_NAME);
                String Unit_Value = c.getString(TAG_UNIT);
                String Period_Value=c.getString(TAG_PERIOD);
                String Description_Value=c.getString(TAG_DESCRIPTION);
                List Values_Value=c.getClass(TAG_VALUE); //118

                //Set JSON Data in TextView
                status.setText(Status_Value);
                name.setText(Name_Value);
                unit.setText(Unit_Value);
                period.setText(Period_Value);
                description.setText(Description_Value);
                ->How to set values for Values?//126

            } catch (JSONException e) {
                e.printStackTrace();
            }

        }
    }

}

JSON：

   {   "status": "ok",  
       "name": "Transaction Rate",  
       "unit":"Transactions Per Second",   
       "period": "minute",  
       "description": "The number of Bitcoin transactions added to the mempool per second.",  
      "values": [
          {
            "x": 1481385360,
            "y": 3.069444444444444
          },
          {
            "x": 1481387340,
            "y": 3.0919444444444437
          },
          {
            "x": 1481389320,
            "y": 3.144861111111111
          } 
      ]
  }

添加getJSONfromURL方法

 public JSONObject getJSONFromUrl(String url) {

        // Making HTTP request
        try {
            // defaultHttpClient
            DefaultHttpClient httpClient = new DefaultHttpClient();
            HttpGet httpGet = new HttpGet(url);

            HttpResponse httpResponse = httpClient.execute(httpGet);
            HttpEntity httpEntity = httpResponse.getEntity();
            is = httpEntity.getContent();

        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    is, "iso-8859-1"), 8);
            StringBuilder sb = new StringBuilder();
            String line = null;
            while ((line = reader.readLine()) != null) {
                sb.append(line + "n");
            }
            is.close();
            json = sb.toString();
        } catch (Exception e) {
            Log.e("Buffer Error", "Error converting result " + e.toString());
        }

        // try parse the string to a JSON object
        try {
            jObj = new JSONObject(json);
        } catch (JSONException e) {
            Log.e("JSON Parser", "Error parsing data " + e.toString());
        }

        // return JSON String
        return jObj;

    }
}

Answer 1

更改，

while ((line = reader.readLine()) != null) {
    sb.append(line + "n");
}

要，

while ((line = reader.readLine()) != null) {
    sb.append(line);
}

您必须打算撰写\n，但忘记撰写\。这是n中迷路JSON字符的来源。

现在您可以使用POJO类和GSON库来解析JSON。

Answer 2

Error parsing data org.json.JSONException: Expected ':'
> after n at character 5 of {n  "status":

你的json中有一个流浪角色。摆脱n。

在Android中解析JSON数组时出错

2 个答案: