Androidアプリでjava.lang.ClassNotFoundExceptionが発生しました。

Question

これは私たManifest.xmlです：

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


    <uses-permission android:name="android.permission.READ_CONTACTS"/> 
    <uses-sdk android:minSdkVersion="15" /> 

    <application 

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

      <activity android:label="@string/app_name" android:name=".TestAndActivity"> 
      <intent-filter> 
       <action android:name="android.intent.action.MAIN" /> 

       <category android:name="android.intent.category.LAUNCHER" /> 
      </intent-filter> 
     </activity> 
     </application> 

</manifest> 

これは私のクラスである：

package com.example.testcode; 

import android.app.ListFragment; 
import android.app.LoaderManager; 
import android.content.CursorLoader; 
import android.content.Loader; 
import android.database.Cursor; 
import android.net.Uri; 
import android.os.Bundle; 
import android.provider.ContactsContract; 
import android.support.v4.widget.SimpleCursorAdapter; 
import android.text.TextUtils; 
import android.util.Log; 
import android.view.Menu; 
import android.view.MenuInflater; 
import android.view.MenuItem; 
import android.view.View; 
import android.widget.ListView; 
import android.widget.SearchView; 
import android.widget.SearchView.OnQueryTextListener; 

public class TestAndActivity extends ListFragment 
     implements OnQueryTextListener, LoaderManager.LoaderCallbacks<Cursor> { 

    // This is the Adapter being used to display the list's data. 
    SimpleCursorAdapter mAdapter; 

    // If non-null, this is the current filter the user has provided. 
    String mCurFilter; 

    @Override 
    public void onActivityCreated(Bundle savedInstanceState) { 
     super.onActivityCreated(savedInstanceState); 

     // Give some text to display if there is no data. In a real 
     // application this would come from a resource. 
     setEmptyText("No phone numbers"); 

     // We have a menu item to show in action bar. 
     setHasOptionsMenu(true); 

     // Create an empty adapter we will use to display the loaded data. 
     mAdapter = new SimpleCursorAdapter(getActivity(), 
       android.R.layout.simple_list_item_2, null, 
       new String[] { ContactsContract.Contacts.DISPLAY_NAME, ContactsContract.Contacts.CONTACT_STATUS }, 
       new int[] { android.R.id.text1, android.R.id.text2 }, 0); 
     setListAdapter(mAdapter); 

     // Start out with a progress indicator. 
     setListShown(false); 

     // Prepare the loader. Either re-connect with an existing one, 
     // or start a new one. 
     getLoaderManager().initLoader(0, null, this); 
    } 

    @Override public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) { 
     // Place an action bar item for searching. 
     MenuItem item = menu.add("Search"); 
     item.setIcon(android.R.drawable.ic_menu_search); 
     item.setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM); 
     SearchView sv = new SearchView(getActivity()); 
     sv.setOnQueryTextListener(this); 
     item.setActionView(sv); 
    } 

    public boolean onQueryTextChange(String newText) { 
     // Called when the action bar search text has changed. Update 
     // the search filter, and restart the loader to do a new query 
     // with this filter. 
     mCurFilter = !TextUtils.isEmpty(newText) ? newText : null; 
     getLoaderManager().restartLoader(0, null, this); 
     return true; 
    } 

    @Override public boolean onQueryTextSubmit(String query) { 
     // Don't care about this. 
     return true; 
    } 

    @Override public void onListItemClick(ListView l, View v, int position, long id) { 
     // Insert desired behavior here. 

     Log.i("FragmentComplexList", "Item clicked: " + id); 
    } 

    // These are the Contacts rows that we will retrieve. 
    static final String[] CONTACTS_SUMMARY_PROJECTION = new String[] { 
     ContactsContract.Contacts._ID, 
     ContactsContract.Contacts.DISPLAY_NAME, 
     ContactsContract.Contacts.CONTACT_STATUS, 
     ContactsContract.Contacts.CONTACT_PRESENCE, 
     ContactsContract.Contacts.PHOTO_ID, 
     ContactsContract.Contacts.LOOKUP_KEY, 
    }; 

    public Loader<Cursor> onCreateLoader(int id, Bundle args) { 
     // This is called when a new Loader needs to be created. This 
     // sample only has one Loader, so we don't care about the ID. 
     // First, pick the base URI to use depending on whether we are 
     // currently filtering. 
     Uri baseUri; 
     if (mCurFilter != null) { 
      baseUri = Uri.withAppendedPath(ContactsContract.Contacts.CONTENT_FILTER_URI, 
        Uri.encode(mCurFilter)); 
     } else { 
      baseUri = ContactsContract.Contacts.CONTENT_URI; 
     } 

     // Now create and return a CursorLoader that will take care of 
     // creating a Cursor for the data being displayed. 
     String select = "((" + ContactsContract.Contacts.DISPLAY_NAME + " NOTNULL) AND (" 
       + ContactsContract.Contacts.HAS_PHONE_NUMBER + "=1) AND (" 
       + ContactsContract.Contacts.DISPLAY_NAME + " != ''))"; 
     return new CursorLoader(getActivity(), baseUri, 
       CONTACTS_SUMMARY_PROJECTION, select, null, 
       ContactsContract.Contacts.DISPLAY_NAME + " COLLATE LOCALIZED ASC"); 
    } 

    public void onLoadFinished(Loader<Cursor> loader, Cursor data) { 
     // Swap the new cursor in. (The framework will take care of closing the 
     // old cursor once we return.) 
     mAdapter.swapCursor(data); 

     // The list should now be shown. 
     if (isResumed()) { 
      setListShown(true); 
     } else { 
      setListShownNoAnimation(true); 
     } 
    } 

    public void onLoaderReset(Loader<Cursor> loader) { 
     // This is called when the last Cursor provided to onLoadFinished() 
     // above is about to be closed. We need to make sure we are no 
     // longer using it. 
     mAdapter.swapCursor(null); 
    } 
} 

これは、携帯電話から連絡先を取得し、それらを表示するAndroidの中ローダーの基本的な実装です。 エラー：

Caused by: java.lang.ClassCastException: com.example.testcode.TestAndActivity cannot be cast to android.app.Activity 

Answer 1

しゃっくりは、あなたは、アプリケーションがフラグメントに、アクティビティを起動設定しようとしているため、例外を取得している（それはListFragmantを拡張するようすなわちTestAndActivityアクティビティではありません）：

<activity android:label="@string/app_name" android:name=".TestAndActivity"> 

フレグマントを使用するときは、アクティビティに存在する必要があります。 the Android Development page here with regard to Fragmentsを読んでください。基本的には、これを解決するには、通常のアクティビティを作成して、そのアクティビティにフラグメントを入れてから置く必要があります。

あなたが読む必要のある開発者の特定の部分は、この例外が発生する行でAdding a fragment to an activity