Magento: How to add check box field in Admin custom module form and populate the check box

How to add Checkbox field in Form:

Open app/code/local/Namespace/CustomModuleName/Block/Adminhtml/ CustomModuleName /Edit/Tab/Form.php and add the below code.

$fieldset->addField('checkbox_name', 'checkbox', array(        
          'name'      => ' checkbox_name ',        
          'onclick' => 'this.value = this.checked ? 1 : 0;',            
          'tabindex' => 1  
        ));

How to re-populate the checkbox on Edit page:

Just add the extra line in ablove code like below:

$fieldset->addField('checkbox_name', 'checkbox', array(        
          'name'      => ' checkbox_name ',        
          'onclick' => 'this.value = this.checked ? 1 : 0;',            
          'tabindex' => 1  
        ))->setIsChecked($model->getCheckboxName());