如何将Glyphicons图标输入？

How can I add a Glyphicons Icons in the input below?

A part of the code:

class GrupoUsuarioForm{
        $this->setAttributes(array(
            'method' => 'POST',
            'class'  => 'formGrupoUsuario',
            'name'   => 'formGrupoUsuario' 
    ));
    $this->setInputFilter(new GrupoUsuarioInputFilter());    

    $dataCadastro = new Text('data_grp');
    $dataCadastro->setValue(date('d/m/Y'))
    ->setAttributes(array(
    //'style' => 'width: 20%',
    'id', 'dataGrp',
    'readOnly' => 'true'
    ));
    $dataCadastro->setLabel('Data do Cadastro');        
    $this->add($dataCadastro);

Would like this return HTML

    <label>Textbox with calendar icon</label>
    <div class="input-append"><input type="text" id="" name="">
    <span   class="add-on"><i class="icon-calendar"></i></span></div>

Where excatly do you want put this icon? You can render form's elements as you want.

In controller:

public function myAction()
{
    return new ViewModel([
        'form' => new GrupoUsuarioForm()
    ]);
}

In your view:

// HTML code here
...
<?php $form = $this->form; ?>
<?php $form->prepare(); ?>
<?php echo $this->form()->openTag($form); ?>
...
<?php echo $this->formLabel($form->get('data_grp')); ?>
<div class="input-group">
    <div class="input-append">
        <?php echo $this->formInput($form->get('data_grp')); ?>
        <span class="add-on"><i class="icon-calendar"></i></span>
    </div>
</div>
...
<?php echo $this->form()->closeTag(); ?>