Сбой приложений для Android по запросу сети

Question

Я включил конвертер валют в свое приложение, но когда я пытаюсь получить результаты из Интернета, приложение падает. Я получаю сообщение об ошибке: android.os.NetworkOnMainThreadException, некоторые говорят, что вам нужно добавить asynctask, чтобы устранить проблему, поскольку она работает в основном потоке. Итак, как я могу это сделать в своем текущем коде?

Ниже приведен код:

import java.io.BufferedReader; 
import java.io.IOException; 
import java.io.InputStream; 
import java.io.InputStreamReader; 

import org.apache.http.HttpEntity; 
import org.apache.http.HttpResponse; 
import org.apache.http.client.ClientProtocolException; 
import org.apache.http.client.HttpClient; 
import org.apache.http.client.methods.HttpGet; 
import org.apache.http.impl.client.DefaultHttpClient; 
import org.json.JSONException; 
import org.json.JSONObject; 


import android.app.Activity; 
import android.os.Bundle; 
import android.os.Handler; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.AdapterView; 
import android.widget.AdapterView.OnItemSelectedListener; 
import android.widget.ArrayAdapter; 
import android.widget.Button; 
import android.widget.Spinner; 
import android.widget.TextView; 
import android.widget.Toast; 

public class Activity_Currency_Converter extends DashBoardActivity { 
    public int to; 
    public int from; 
    public String [] val; 
    public String s; 
    public Handler handler; 

    /** Called when the activity is first created. */ 
    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_currency_converter); 
     Spinner s1 = (Spinner) findViewById(R.id.spinner1); 
     Spinner s2 = (Spinner) findViewById(R.id.spinner2); 
     ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(
       this, R.array.name, android.R.layout.simple_spinner_item); 
     adapter.setDropDownViewResource(android.R.layout.select_dialog_singlechoice); 
     val = getResources().getStringArray(R.array.value); 
     s1.setAdapter(adapter); 
     s2.setAdapter(adapter); 
     s1.setOnItemSelectedListener(new spinOne(1)); 
     s2.setOnItemSelectedListener(new spinOne(2)); 
     Button b = (Button) findViewById(R.id.button1); 
     b.setOnClickListener(new OnClickListener(){ 
      public void onClick(View v) { 
       TextView t = (TextView) findViewById(R.id.textView4); 
       if(from == to) 
       { 
        Toast.makeText(getApplicationContext(), "Invalid", 4000).show(); 
       } 
       else 
       {          
         try { 
         s = getJson("http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20yahoo.finance.xchange%20where%20pair%20in%20(%22"+val[from]+val[to]+"%22)&format=json&diagnostics=true&env=store%3A%2F%2Fdatatables.org%2Falltableswithkeys&callback=");      
         JSONObject jObj; 
         jObj = new JSONObject(s); 
         String exResult = jObj.getJSONObject("query").getJSONObject("results").getJSONObject("rate").getString("Rate"); 
         t.setText(exResult); 
         } catch (JSONException e) { 
          // TODO Auto-generated catch block 
          e.printStackTrace(); 
         } 
         catch (ClientProtocolException e) { 
          // TODO Auto-generated catch block 
          e.printStackTrace(); 
         } catch (IOException e) { 
          // TODO Auto-generated catch block 
          e.printStackTrace(); 
         }              
        }           
       }        
     }); 
    } 
    public String getJson(String url)throws ClientProtocolException, IOException { 

     StringBuilder build = new StringBuilder(); 
     HttpClient client = new DefaultHttpClient(); 
     HttpGet httpGet = new HttpGet(url); 
     HttpResponse response = client.execute(httpGet); 
     HttpEntity entity = response.getEntity(); 
     InputStream content = entity.getContent(); 
     BufferedReader reader = new BufferedReader(new InputStreamReader(content)); 
     String con; 
     while ((con = reader.readLine()) != null) { 
        build.append(con); 
       } 
     return build.toString(); 
    } 
    private class spinOne implements OnItemSelectedListener 
    { 
     int ide; 
     spinOne(int i) 
     { 
      ide =i; 
     } 
     public void onItemSelected(AdapterView<?> parent, View view, 
       int index, long id) { 
      if(ide == 1) 
       from = index; 
      else if(ide == 2) 
       to = index; 

     } 

     public void onNothingSelected(AdapterView<?> arg0) { 
      // TODO Auto-generated method stub 
     } 

    } 
} 

Logcat журнала:

11-27 13:58:17.120: E/AndroidRuntime(1470): android.os.NetworkOnMainThreadException 
11-27 13:58:17.120: E/AndroidRuntime(1470):  at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1133) 
11-27 13:58:17.120: E/AndroidRuntime(1470):  at java.net.InetAddress.lookupHostByName(InetAddress.java:385) 
11-27 13:58:17.120: E/AndroidRuntime(1470):  at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236) 
11-27 13:58:17.120: E/AndroidRuntime(1470):  at java.net.InetAddress.getAllByName(InetAddress.java:214) 
11-27 13:58:17.120: E/AndroidRuntime(1470):  at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137) 
11-27 13:58:17.120: E/AndroidRuntime(1470):  at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164) 
11-27 13:58:17.120: E/AndroidRuntime(1470):  at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119) 
11-27 13:58:17.120: E/AndroidRuntime(1470):  at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360) 
11-27 13:58:17.120: E/AndroidRuntime(1470):  at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555) 
11-27 13:58:17.120: E/AndroidRuntime(1470):  at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487) 
11-27 13:58:17.120: E/AndroidRuntime(1470):  at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465) 

Answer 1

Try это ,

public class Activity_Currency_Converter extends DashBoardActivity { 
    public int to; 
    public int from; 
    public String [] val; 
    public String s; 
    public Handler handler; 

    /** Called when the activity is first created. */ 
    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_currency_converter); 
     Spinner s1 = (Spinner) findViewById(R.id.spinner1); 
     Spinner s2 = (Spinner) findViewById(R.id.spinner2); 
     ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(
       this, R.array.name, android.R.layout.simple_spinner_item); 
     adapter.setDropDownViewResource(android.R.layout.select_dialog_singlechoice); 
     val = getResources().getStringArray(R.array.value); 
     s1.setAdapter(adapter); 
     s2.setAdapter(adapter); 
     s1.setOnItemSelectedListener(new spinOne(1)); 
     s2.setOnItemSelectedListener(new spinOne(2)); 
     Button b = (Button) findViewById(R.id.button1); 
     b.setOnClickListener(new OnClickListener(){ 
      public void onClick(View v) { 
       TextView t = (TextView) findViewById(R.id.textView4); 
       if(from == to) 
       { 
        Toast.makeText(getApplicationContext(), "Invalid", 4000).show(); 
       } 
       else 
       {          
         new GetResponseData(t).execute();        
        }           
       }        
     }); 
    } 
    public String getJson(String url)throws ClientProtocolException, IOException { 

     StringBuilder build = new StringBuilder(); 
     HttpClient client = new DefaultHttpClient(); 
     HttpGet httpGet = new HttpGet(url); 
     HttpResponse response = client.execute(httpGet); 
     HttpEntity entity = response.getEntity(); 
     InputStream content = entity.getContent(); 
     BufferedReader reader = new BufferedReader(new InputStreamReader(content)); 
     String con; 
     while ((con = reader.readLine()) != null) { 
        build.append(con); 
       } 
     return build.toString(); 
    } 
    private class spinOne implements OnItemSelectedListener 
    { 
     int ide; 
     spinOne(int i) 
     { 
      ide =i; 
     } 
     public void onItemSelected(AdapterView<?> parent, View view, 
       int index, long id) { 
      if(ide == 1) 
       from = index; 
      else if(ide == 2) 
       to = index; 

     } 

     public void onNothingSelected(AdapterView<?> arg0) { 
      // TODO Auto-generated method stub 
     } 

    } 
    class GetResponseData extends AsyncTask<String, String, String> { 
     private ProgressDialog dialog; 
     private ArrayList<String> titleList; 
     private TextView textView; 

     public GetResponseData(TextView textView) { 
      this.textView=textView; 
     } 

     @Override 
     protected void onPreExecute() { 
     super.onPreExecute(); 
     dialog = ProgressDialog.show(Activity_Currency_Converter.this, "", "Loading", 
     false); 
     } 

     @Override 
     protected String doInBackground(String... params) { 

      try { 
       String s = getJson("http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20yahoo.finance.xchange%20where%20pair%20in%20(%22"+val[from]+val[to]+"%22)&format=json&diagnostics=true&env=store%3A%2F%2Fdatatables.org%2Falltableswithkeys&callback=");      
       JSONObject jObj; 
       jObj = new JSONObject(s); 
       String exResult = jObj.getJSONObject("query").getJSONObject("results").getJSONObject("rate").getString("Rate"); 
       return exResult; 
       } catch (JSONException e) { 
        // TODO Auto-generated catch block 
        e.printStackTrace(); 
        return null; 
       } 
       catch (ClientProtocolException e) { 
        // TODO Auto-generated catch block 
        e.printStackTrace(); 
        return null; 
       } catch (IOException e) { 
        // TODO Auto-generated catch block 
        e.printStackTrace(); 
        return null; 
       }      




     } 

     @Override 
     protected void onPostExecute(String result) { 
     super.onPostExecute(result); 
     if (dialog != null) 
      dialog.dismiss(); 
     if(result!=null) 
     { 
      textView.setText(result); 
     } 
     } 

     } 
} 

Answer 2

Использование Asynchtask для выполнения операций, связанных с Network .. Chack это для более подробной информации NetworkOnMainThread и Asynchtask

Answer 3

Сделайте StringBuilder уровень класса, создайте свой ProgressDialog соответственно. Внутри ваш метод getJSON создать асинхронную задачу как этого

new AsyncTask<Void, Void, Void>() { 

     protected void onPreExecute() { 
      //Your code 
     } 

     @Override 
     protected Void doInBackground(Void... params) { 
     StringBuilder build = new StringBuilder(); 
     HttpClient client = new DefaultHttpClient(); 
     HttpGet httpGet = new HttpGet(url); 
     HttpResponse response = client.execute(httpGet); 
     HttpEntity entity = response.getEntity(); 
     InputStream content = entity.getContent(); 
     BufferedReader reader = new BufferedReader(new InputStreamReader(content)); 
     String con; 
     while ((con = reader.readLine()) != null) { 
        build.append(con); 
       } 
     return null; 
     } 

     protected void onPostExecute(Void result) { 
      //Update UI from here 
     } 
     }.execute(); 

Answer 4

Использование AsyncTask в

class myAsyncTask extends AsyncTask<String[] ,String,String> 
{ 
    String s=null; 
    String output=null; 
    JSONObject main; 

    @Override 
    protected void onPreExecute() 
    { 


    } 

    @Override 
    protected String doInBackground(String[]... val) { 

     s = getJson("http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20yahoo.finance.xchange%20where%20pair%20in%20(%22"+val[from]+val[to]+"%22)&format=json&diagnostics=true&env=store%3A%2F%2Fdatatables.org%2Falltableswithkeys&callback=");      
        JSONObject jObj; 
        jObj = new JSONObject(s); 
        String exResult = jObj.getJSONObject("query").getJSONObject("results").getJSONObject("rate").getString("Rate"); 

     return exResult; 
    } 
    @Override 
    protected void onPostExecute(String result) { 
     super.onPostExecute(result); 
     t.setText(result); 
      } 
} 

, а затем вызвать следующий метод из «еще» блока

new myAsyncTask().execute(val); 

Answer 5

В приложении падает из-за политики строгого режима вставьте ниже указанных строк, прежде чем отправлять запрос на обслуживание или подключение к сети:

ThreadPolicy tp = ThreadPolicy.LAX; 
StrictMode.setThreadPolicy(tp); 

Надеется, что это помогает вам :)