Unfortunately, CadastroCaelium

Aula 03,

ao executar o projeto exibe a tela rapidamente e depois aparece a mensagem Unfortunately, CadastroCaelium.

Alguém pode me ajudar? aparentemente esta correto

Aparece isso no Log:

01-29 14:30:34.239: E/AndroidRuntime(1285): FATAL EXCEPTION: main
01-29 14:30:34.239: E/AndroidRuntime(1285): Process: br.com.caelum.cadastrocaelum, PID: 1285
01-29 14:30:34.239: E/AndroidRuntime(1285): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{br.com.caelum.cadastrocaelum/br.com.caelum.cadastrocael.ListaAlunosActivity}: java.lang.ClassNotFoundException: Didn't find class "br.com.caelum.cadastrocael.ListaAlunosActivity" on path: DexPathList[[zip file "/data/app/br.com.caelum.cadastrocaelum-2.apk"],nativeLibraryDirectories=[/data/app-lib/br.com.caelum.cadastrocaelum-2, /system/lib]]

Manifest

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="br.com.caelum.cadastrocaelum"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="21" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >


        <activity android:name="br.com.caelum.cadastrocael.ListaAlunosActivity">

            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>
                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>

        </activity>

    </application>

</manifest>

XML

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

<ListView 
    android:id="@+id/lista_alunos"
    android:layout_width="match_parent"
    android:layout_height="match_parent"

    ></ListView>

</LinearLayout>

Classe

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;

import br.com.caelum.cadastrocaelum.R;


public class ListaAlunosActivity extends Activity{

    private ListView listaAlunos;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);

        String[] alunos = {"Douglas","Raphael","Vanuza"};

        //layout pronto da classe R. do android
        int layout = android.R.layout.simple_list_item_1;

        //Criando o adpter para passar o array do Java para android

        ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, layout,alunos);

        //fazendo a ponte entre XML e Java, e o devido Cast
        listaAlunos=(ListView)findViewById(R.id.lista_alunos);

        // Associar  o adpter criado para o LIstView

        listaAlunos.setAdapter(adapter);

        // Atribuindo comportamentos Listener ao clicar no item da lista

        listaAlunos.setOnItemClickListener(new OnItemClickListener() {
            // ctrl+1 para implementar o metodo do contrato
            @Override
            public void onItemClick(AdapterView<?> adapter, View view, int posicao,
                    long id) {
                // TODO Auto-generated method stub
                Toast.makeText(ListaAlunosActivity.this, "A posição é: "+posicao, Toast.LENGTH_SHORT).show();
            }
        });


    }

}