org.json.JSONException：

Question

の文字0での入力の終わり、私は次のチュートリアルに従ってきたが、私は私のコードでシステムエラーを取得： http://www.informit.com/articles/article.aspx?p=2154675&seqNum=4

は、ここですべてのエラーです：

 
W/EGL_emulation: eglSurfaceAttrib not implemented 
W/OpenGLRenderer: Failed to set EGL_SWAP_BEHAVIOR on surface 0x7f651f4e3780, error=EGL_SUCCESS 
W/DefaultRequestDirector: Authentication error: Unable to respond to any of these challenges: {} 
W/System.err: org.json.JSONException: End of input at character 0 of 
W/System.err:  at org.json.JSONTokener.syntaxError(JSONTokener.java:450) 
W/System.err:  at org.json.JSONTokener.nextValue(JSONTokener.java:97) 
W/System.err:  at org.json.JSONObject.(JSONObject.java:156) 
W/System.err:  at org.json.JSONObject.(JSONObject.java:173) 
W/System.err:  at com.example.theol.opsc7312_assign2_14001515_theolin_naidoo.MainActivity$ReadJSONFeed.onPostExecute(MainActivity.java:74) 
W/System.err:  at com.example.theol.opsc7312_assign2_14001515_theolin_naidoo.MainActivity$ReadJSONFeed.onPostExecute(MainActivity.java:46) 
W/System.err:  at android.os.AsyncTask.finish(AsyncTask.java:636) 
W/System.err:  at android.os.AsyncTask.access$500(AsyncTask.java:177) 
W/System.err:  at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:653) 
W/System.err:  at android.os.Handler.dispatchMessage(Handler.java:102) 
W/System.err:  at android.os.Looper.loop(Looper.java:135) 
W/System.err:  at android.app.ActivityThread.main(ActivityThread.java:5254) 
W/System.err:  at java.lang.reflect.Method.invoke(Native Method) 
W/System.err:  at java.lang.reflect.Method.invoke(Method.java:372) 
W/System.err:  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903) 
W/System.err:  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698) 

Application terminated. 

ここです私のコード：

import android.os.Bundle; 
import android.app.Activity; 
import android.widget.Button; 
import android.widget.EditText; 
import android.widget.TextView; 
import android.view.View; 
import org.apache.http.client.methods.HttpPost; 
import org.json.JSONException; 
import org.apache.http.impl.client.DefaultHttpClient; 
import org.apache.http.client.HttpClient; 
import org.apache.http.HttpResponse; 
import org.apache.http.HttpEntity; 
import java.io.InputStream; 
import java.io.BufferedReader; 
import java.io.InputStreamReader; 
import android.os.AsyncTask; 
import org.json.JSONObject; 
import org.apache.http.StatusLine; 
import org.json.JSONArray; 
import java.text.NumberFormat; 

public class MainActivity extends Activity { 
    String city=""; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 

     Button submitButton = (Button)this.findViewById(R.id.submit_btn); 

     submitButton.setOnClickListener(new Button.OnClickListener(){ 
      public void onClick(View v) { 
       String country=""; 
       EditText cityName = (EditText) findViewById(R.id.city_name); 
       city=cityName.getText().toString(); 

       String url="http://api.openweathermap.org/data/2.5/weather?q="+city; 
       new ReadJSONFeed().execute(url); 

      } 
     }); 
    } 
    private class ReadJSONFeed extends AsyncTask<String, String, String> { 
     protected void onPreExecute() {} 
     @Override 
     protected String doInBackground(String... urls) { 
      HttpClient httpclient = new DefaultHttpClient(); 
      StringBuilder builder = new StringBuilder(); 
      HttpPost httppost = new HttpPost(urls[0]); 
      try { 
       HttpResponse response = httpclient.execute(httppost); 
       StatusLine statusLine = response.getStatusLine(); 
       int statusCode = statusLine.getStatusCode(); 
       if (statusCode == 200) { 
        HttpEntity entity = response.getEntity(); 
        InputStream content = entity.getContent(); 
        BufferedReader reader = new BufferedReader(new InputStreamReader(content)); 
        String line; 
        while ((line = reader.readLine()) != null) { 
         builder.append(line); 
        } 
       } 
      } catch (Exception e) { 
       e.printStackTrace(); 
      } 
      return builder.toString(); 
     } 
     protected void onPostExecute(String result) { 
      String weatherInfo="Weather Report of "+city +" is: \n"; 
      try{ 

       JSONObject jsonObject = new JSONObject(result); 
       JSONObject jscoordObject = new JSONObject(jsonObject.getString("coord")); 
       weatherInfo+="Longitude: "+jscoordObject.getString("lon")+"\n"; 
       weatherInfo+="Latitude: "+jscoordObject.getString("lat")+"\n"; 
       JSONArray jsweatherObject = new JSONArray(jsonObject.getString("weather")); 
       JSONObject jweatherObject = jsweatherObject.getJSONObject(0); 
       weatherInfo+="Clouds: "+jweatherObject.getString("description")+"\n"; 
       JSONObject jsmainObject = new JSONObject(jsonObject.getString("main")); 
       weatherInfo+="Humidity: "+jsmainObject.getString("humidity")+"% \n"; 
       weatherInfo+="Atmospheric Pressure: "+jsmainObject.getString("pressure")+"hPa \n"; 
       float temp=Float.parseFloat(jsmainObject.getString("temp")); 
       temp = temp - (float) 273.15; 
       NumberFormat df = NumberFormat.getNumberInstance(); 
       df.setMaximumFractionDigits(2); 
       weatherInfo+="Temperature: "+ String.valueOf(df.format(temp)) +" C\n"; 
       JSONObject jswindObject = new JSONObject(jsonObject.getString("wind")); 
       weatherInfo+="Wind Speed: "+jswindObject.getString("speed")+"mps \n"; 
      } 
      catch (JSONException e) { 
       e.printStackTrace(); 
      } 
      TextView resp = (TextView) findViewById(R.id.response); 
      if(weatherInfo.trim().length() >0) 
       resp.setText(weatherInfo); 
      else 
       resp.setText("Sorry no match found"); 
     } 
    } 
} 

Answer 1

エラーに基づいて、JSONが戻ってきていないため、HTTPエラーが発生している可能性があります。

Logの場合は、それを解析しようとする前にresultという値が表示されます。

---

ただし、これに注意する必要があります。

"APIにアクセスするには、無料または有料プランの場合はAPIキーにサインアップする必要があります。
- http://openweathermap.org/api

、あなたのURLに追加し、APIキーを取りに行く、つまりuse the API key

にここを参照してください。たとえば、

String API_KEY = "XXXXxxxx"; 
String url = "http://.../weather?q=" + city + "&APPID=" + API_KEY;