android ClassCastException à android.app.Application

Question

j'ai l'exception suivante quand j'exécutant l'application suivante

Activité:

package com.google.android.SmartStudentmCompanion; 


import java.io.BufferedReader; 
import java.io.IOException; 
import java.util.ArrayList; 
import java.util.List; 

import org.apache.http.HttpResponse; 
import org.apache.http.NameValuePair; 
import org.apache.http.client.HttpClient; 
import org.apache.http.client.entity.UrlEncodedFormEntity; 
import org.apache.http.client.methods.HttpPost; 
import org.apache.http.message.BasicNameValuePair; 
import org.apache.http.util.EntityUtils; 

import android.app.Activity; 
import android.content.Intent; 
import android.os.Bundle; 
import android.view.View; 
import android.widget.Button; 
import android.widget.EditText; 
import android.widget.Toast; 

public class Login extends Activity{ 
    public static String ip_address="192.168.1.101"; 

    EditText username; 
    EditText password; 
    Button login; 
    Button exit; 
    Toast toast; 

    /** Called when the activity is first created. */ 
    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.loginscreen); 
     System.out.println("onCreate()..."); 
     username = (EditText) findViewById(R.id.username); 
     password = (EditText) findViewById(R.id.password); 

     this.login = (Button)findViewById(R.id.loginButton); 
     this.login.setOnClickListener(new View.OnClickListener() { 
      String usrnm; 
      String pwd; 

      @Override 
      public void onClick(View v) { 
       usrnm = username.getText().toString(); 
       pwd = password.getText().toString(); 
       System.out.println("onClick()..."); 
       int length = 0; 
       try { 
        System.out.println("hello"); 
        String page = executeHttpPost(usrnm,pwd); 
        System.out.println(page); 
        length = page.length(); 
       } catch (Exception e) { 
        // TODO Auto-generated catch block 
        e.printStackTrace(); 
       } 

       if (length == 0){ 
        Toast.makeText(getApplicationContext(), 
          "Invalid username and/or password", 
          Toast.LENGTH_SHORT).show(); 
       } 
       else { 
        /*Toast.makeText(getApplicationContext(), 
          "Valid username and password", 
          Toast.LENGTH_SHORT).show();*/ 
        Intent myIntent = new Intent(v.getContext(), VideoViewer.class); 
        startActivityForResult(myIntent, 0); 
       } 

      } 
     }); 

     this.exit = (Button)findViewById(R.id.exitButton); 
     this.exit.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View v) { 
       finish(); 
      } 
     }); 
    } 


    public String executeHttpPost(String username, String password) throws Exception { 
     BufferedReader in = null; 

     try { 

      ApplicationEx app = (ApplicationEx)this.getApplication(); 

      HttpClient client = app.getHttpClient(); 
      HttpPost request = new HttpPost("http://"+ip_address+"/smartstudentmcompanion/check.php"); 
      List<NameValuePair> postParameters = new ArrayList<NameValuePair>(); 
      postParameters.add(new BasicNameValuePair("un", username)); 
      postParameters.add(new BasicNameValuePair("pwd", password)); 
      UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(postParameters); 
      request.setEntity(formEntity); 

      HttpResponse response = client.execute(request); 

      /*in = new BufferedReader(new InputStreamReader(response.getEntity().getContent())); 
      StringBuffer sb = new StringBuffer(""); 
      String line = ""; 
      String NL = System.getProperty("line.separator"); 
      while ((line = in.readLine()) != null) { 
       sb.append(line + NL); 
      } 
      in.close();*/ 
      String page = EntityUtils.toString(response.getEntity()); 
      System.out.println("page: " + page); 
      return page; 
      } finally { 
      if (in != null) { 
       try { 
        in.close(); 
       } catch (IOException e) { 
        e.printStackTrace(); 
       } 
      } 
     } 
    } 
} 

Application:

package com.google.android.SmartStudentmCompanion; 

import org.apache.http.HttpVersion; 
import org.apache.http.client.HttpClient; 
import org.apache.http.conn.ClientConnectionManager; 
import org.apache.http.conn.scheme.PlainSocketFactory; 
import org.apache.http.conn.scheme.Scheme; 
import org.apache.http.conn.scheme.SchemeRegistry; 
import org.apache.http.conn.ssl.SSLSocketFactory; 
import org.apache.http.impl.client.DefaultHttpClient; 
import org.apache.http.impl.conn.tsccm.ThreadSafeClientConnManager; 
import org.apache.http.params.BasicHttpParams; 
import org.apache.http.params.HttpParams; 
import org.apache.http.params.HttpProtocolParams; 
import org.apache.http.protocol.HTTP; 
import android.app.Application; 
import android.util.Log; 

public class ApplicationEx extends Application { 

    private static final String TAG = "ApplicationEx"; 
    private HttpClient httpClient; 
    @Override 
    public void onCreate(){ 
     super.onCreate(); 
     httpClient = createHttpClient(); 
    } 

    @Override 
    public void onLowMemory() { 
     super.onLowMemory(); 
     shutdownHttpClient(); 
    } 

    @Override 
    public void onTerminate() { 
     super.onTerminate(); 
     shutdownHttpClient(); 
    } 
    private HttpClient createHttpClient(){ 
     Log.d(TAG,"createHttpClient()..."); 
     HttpParams params = new BasicHttpParams(); 
     HttpProtocolParams.setVersion(params, HttpVersion.HTTP_1_1); 
     HttpProtocolParams.setContentCharset(params, HTTP.DEFAULT_CONTENT_CHARSET); 
     HttpProtocolParams.setUseExpectContinue(params, true); 
     SchemeRegistry schReg = new SchemeRegistry(); 
     schReg.register(new Scheme("http", 
       PlainSocketFactory.getSocketFactory(), 80)); 
     schReg.register(new Scheme("https", 
       SSLSocketFactory.getSocketFactory(), 443)); 
     ClientConnectionManager conMgr = new ThreadSafeClientConnManager(params,schReg); 
     return new DefaultHttpClient(conMgr, params); 
    } 

    public HttpClient getHttpClient() { 
     return httpClient; 
    } 

    private void shutdownHttpClient() { 
     if(httpClient!=null && httpClient.getConnectionManager()!=null) { 
      httpClient.getConnectionManager().shutdown(); 
     } 
    } 
} 

manifeste:

<?xml version="1.0" encoding="utf-8"?> 
<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
     package="com.google.android.SmartStudentmCompanion" 
     android:versionCode="1" 
     android:versionName="1.0"> 



    <application android:icon="@drawable/icon" android:label="@string/app_name"> 
     <activity android:name=".Login" 
        android:label="@string/app_name"> 
      <intent-filter> 
       <action android:name="android.intent.action.MAIN" /> 
       <category android:name="android.intent.category.LAUNCHER" /> 
      </intent-filter> 
     </activity> 
     <activity android:name=".VideoViewer"></activity> 


    </application> 

    <uses-permission 
     android:name="android.permission.INTERNET" /> 
    <uses-sdk android:minSdkVersion="8" /> 

</manifest> 

Answer 1

Dans votre changement manifeste

<application android:icon="@drawable/icon" android:label="@string/app_name"> 

à

<application android:icon="@drawable/icon" android:label="@string/app_name" 
    android:name=".ApplicationEx"> 

Puisque vous ne l'avez pas dit le android:name pour le <applicaton> le système d'exploitation recherche la classe par défaut Application. Afin de pointer vers votre sous-classe Application, vous devez utiliser l'attribut android:name.