public void onClick(View v) {
        if( v == voltar ) {
            setResult( RESULT_CANCELED );
            finish( );
        }
        else if( v == avancar ) {
            if( ! Utils.validateCPF( editCPF ) ) return;
            if( ! Utils.validateEmail( editEmail ) ) return;

            final ProgressDialog dialog = ProgressDialog.show( this, "Verificando", "Por favor, aguarde...", true );
            final String edCpf = editCPF.getCleanText();
            final String edEmail = editEmail.getText().toString();
            final Activity instance = this;

            Runnable runnable = new Runnable() {
                public void run() {

                    String reqUrl = "http://url/login?";
                    String reqParams = "";
                    try {
                        reqParams = "cpf=" + URLEncoder.encode( edCpf, "UTF-8" ) +"&email=" +/* URLEncoder.encode( edEmail, "UTF-8" )*/ (String) edEmail;
                    } catch (UnsupportedEncodingException e1) {
                        e1.printStackTrace();
                    }
                         Log.d("",reqUrl + reqParams);
                    StringBuilder is = Utils.sendHttpGet( reqUrl + reqParams );

                    instance.runOnUiThread( new Runnable() {
                        public void run() {
                            dialog.dismiss( );
                        }
                    });

                    String msg = null;
                    if( is == null ) {
                        msg = "Erro ao verificar cadastro.\nCertifique-se de que a conexão com a internet esteja ativada e tente novamente.";
                    }
                    else {
                        msg = "Erro interno ao verificar cadastro.";
                        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
                        try {
                            DocumentBuilder builder = factory.newDocumentBuilder( );
                            Document dom = builder.parse( new ByteArrayInputStream( is.toString().getBytes() ) );
                            Element  root = dom.getDocumentElement( );
                            NodeList list = root.getElementsByTagName( "UserClientEntity" );
                            if( list.getLength() < 1 ) {
                                msg = "Usuário não encontrado.";
                            }
                            else {
                                String cpf = "";
                                msg = "Usuário não encontrado.";

                                NodeList user = list.item( 0 ).getChildNodes( );

                                for( int i = 0; i < user.getLength(); ++i ) {
                                    if( user.item( i ).getNodeName().equals( "cpf" ) ) {
                                        cpf = user.item( i ).getChildNodes().item(0).getNodeValue();
                                        if( cpf == null ) {
                                            cpf = "";
                                        }
                                        break;
                                    }
                                }

                                if( cpf.equals( edCpf ) ) {

                                    instance.runOnUiThread( new Runnable() {
                                        public void run() {
                                            LastLoginData.setCpf( edCpf );
                                            LastLoginData.setEmail( edEmail );
                                            LastLoginData.saveData( instance );

                                            setResult( RESULT_OK );
                                            finish( );
                                        }
                                    });
                                    msg = null;
                                }
                            }
                        }
                        catch( Exception e ) {
                        }
                    }
                    if( msg != null ) {
                        final String xmsg = msg;
                        instance.runOnUiThread( new Runnable() {
                            public void run() {
                                Utils.showInformation( instance, "Atenção", xmsg );
                            }
                        });
                    }
                }
            };
            Thread thread = new Thread( runnable );
            thread.start( );
        }
    }