Quick simple_form + Bootstrap3 hack

simple_form_bootstrap.rb

# config/initializers/simple_form_bootstrap.rb

# https://github.com/plataformatec/simple_form/issues/857
# https://gist.github.com/adamico/6510093

class CollectionCheckBoxesInput < SimpleForm::Inputs::CollectionCheckBoxesInput
  def item_wrapper_class
    "checkbox-inline"
  end
end

class CollectionRadioButtonsInput < SimpleForm::Inputs::CollectionRadioButtonsInput
  def item_wrapper_class
    "radio-inline"
  end
end

inputs = %w[
  CollectionSelectInput
  DateTimeInput
  FileInput
  GroupedCollectionSelectInput
  NumericInput
  PasswordInput
  RangeInput
  StringInput
  TextInput
]

inputs.each do |input_type|
  superclass = "SimpleForm::Inputs::#{input_type}".constantize

  new_class = Class.new(superclass) do
    def input_html_classes
      super.push('form-control')
    end
  end

  Object.const_set(input_type, new_class)
end

# Use this setup block to configure all options available in SimpleForm.
SimpleForm.setup do |config|
  config.boolean_style = :nested

  config.wrappers :bootstrap3, tag: 'div', class: 'form-group', error_class: 'has-error',
    defaults: { input_html: { class: 'default_class' } } do |b|

    b.use :html5
    b.use :min_max
    b.use :maxlength
    b.use :placeholder

    b.optional :pattern
    b.optional :readonly

    b.use :label_input
    b.use :hint,  wrap_with: { tag: 'span', class: 'help-block' }
    b.use :error, wrap_with: { tag: 'span', class: 'help-block has-error' }
  end

  config.wrappers :bootstrap3_horizontal, tag: 'div', class: 'form-group', error_class: 'has-error',
    defaults: { input_html: { class: 'default-class '}, wrapper_html: { class: "col-lg-10 col-md-10"} } do |b|

    b.use :html5
    b.use :min_max
    b.use :maxlength
    b.use :placeholder

    b.optional :pattern
    b.optional :readonly

    b.use :label
    b.wrapper :right_column, tag: :div do |component|
      component.use :input
    end
    b.use :hint,  wrap_with: { tag: 'span', class: 'help-block' }
    b.use :error, wrap_with: { tag: 'span', class: 'help-block has-error' }
  end

  config.wrappers :group, tag: 'div', class: "form-group", error_class: 'has-error',
    defaults: { input_html: { class: 'default-class '} }  do |b|

    b.use :html5
    b.use :min_max
    b.use :maxlength
    b.use :placeholder

    b.optional :pattern
    b.optional :readonly

    b.use :label
    b.use :input, wrap_with: { class: "input-group" }
    b.use :hint,  wrap_with: { tag: 'span', class: 'help-block' }
    b.use :error, wrap_with: { tag: 'span', class: 'help-block has-error' }
  end

  config.default_wrapper = :bootstrap3
end