title: Android - openOrCreateDatabase - null pointer Exception
body: <p>I have my class DAO, and when i call my class conexao the method return null, but why?</p>
  
  <pre><code>public void criarBanco() {
          Conexao conexao = new Conexao();
          try {
              BANCO_DE_DADOS = conexao.abrirBanco(); // &lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;
              String SQL = "CREATE TABLE IF NOT EXISTS tablecadastropessoa ( _id INTEGER PRIMARY KEY, nome TEXT, telefone TEXT)";
              BANCO_DE_DADOS.execSQL(SQL);
          } catch (Exception e) {
              Log.i(TAG, "Erro ao criar o banco" + e);
          } finally {
              //conexao.fecharBanco(BANCO_DE_DADOS);
          }
      }
  
      // ABRIR BANCO
      public SQLiteDatabase abrirBanco(){
          try {
              BANCO_DE_DADOS = openOrCreateDatabase(NOME_BANCO, MODE_PRIVATE, null); // RETURN NULL
          } catch (Exception e) {
              Util.exibirMensagem("Erro ao criar o banco: " + e, AulaCadastroActivity.context);
              Log.i(TAG, "Erro ao abrir o banco: " + e);
          }
          return BANCO_DE_DADOS;
      }
  </code></pre>
  
  <p>ERROR IS</p>
  
  <pre><code>07-05 13:12:54.800: E/AndroidRuntime(223): Uncaught handler: thread main exiting due to uncaught exception
  07-05 13:12:54.811: E/AndroidRuntime(223): java.lang.RuntimeException: Unable to start activity ComponentInfo{br.cadastro/br.cadastro.AulaCadastroActivity}: java.lang.NullPointerException
  07-05 13:12:54.811: E/AndroidRuntime(223):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496)
  07-05 13:12:54.811: E/AndroidRuntime(223):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512)
  07-05 13:12:54.811: E/AndroidRuntime(223):  at android.app.ActivityThread.access$2200(ActivityThread.java:119)
  07-05 13:12:54.811: E/AndroidRuntime(223):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863)
  07-05 13:12:54.811: E/AndroidRuntime(223):  at android.os.Handler.dispatchMessage(Handler.java:99)
  07-05 13:12:54.811: E/AndroidRuntime(223):  at android.os.Looper.loop(Looper.java:123)
  07-05 13:12:54.811: E/AndroidRuntime(223):  at android.app.ActivityThread.main(ActivityThread.java:4363)
  07-05 13:12:54.811: E/AndroidRuntime(223):  at java.lang.reflect.Method.invokeNative(Native Method)
  07-05 13:12:54.811: E/AndroidRuntime(223):  at java.lang.reflect.Method.invoke(Method.java:521)
  07-05 13:12:54.811: E/AndroidRuntime(223):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
  07-05 13:12:54.811: E/AndroidRuntime(223):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
  07-05 13:12:54.811: E/AndroidRuntime(223):  at dalvik.system.NativeStart.main(Native Method)
  07-05 13:12:54.811: E/AndroidRuntime(223): Caused by: java.lang.NullPointerException
  07-05 13:12:54.811: E/AndroidRuntime(223):  at android.content.ContextWrapper.openOrCreateDatabase(ContextWrapper.java:193)
  07-05 13:12:54.811: E/AndroidRuntime(223):  at br.cadastro.Conexao.abrirBanco(Conexao.java:20)
  07-05 13:12:54.811: E/AndroidRuntime(223):  at br.cadastro.ContadosDAO.criarBanco(ContadosDAO.java:27)
  07-05 13:12:54.811: E/AndroidRuntime(223):  at br.cadastro.AulaCadastroActivity.inicializar(AulaCadastroActivity.java:81)
  07-05 13:12:54.811: E/AndroidRuntime(223):  at br.cadastro.AulaCadastroActivity.onCreate(AulaCadastroActivity.java:27)
  07-05 13:12:54.811: E/AndroidRuntime(223):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
  07-05 13:12:54.811: E/AndroidRuntime(223):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459)
  07-05 13:12:54.811: E/AndroidRuntime(223):  ... 11 more
  </code></pre>