Class: TableHelper::Header

Inherits:
HtmlElement show all
Defined in:
lib/table_helper/header.rb

Overview

Represents the header of the table. In HTML, you can think of this as the <thead> tag of the table.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(table) ⇒ Header

Creates a new header for the given table.

If the class is known, then the header will be pre-filled with the columns defined in that class (assuming it’s an ActiveRecord class).



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# File 'lib/table_helper/header.rb', line 24

def initialize(table)
  super()
  
  @table = table
  @row = Row.new(self)
  @hide_when_empty = true
  
  # If we know what class the objects in the collection are and we can
  # figure out what columns are defined in that class, then we can
  # pre-fill the header with those columns so that the user doesn't
  # have to
  klass = table.klass
  if klass && klass.respond_to?(:column_names)
    if !table.empty? && klass < ActiveRecord::Base
      # Make sure only the attributes that have been loaded are used
      column_names = table.collection.first.attributes.keys
    else
      # Assume all attributes are loaded
      column_names = klass.column_names
    end
    
    column(*column_names.map(&:to_sym))
  end
  
  @customized = false
end

Instance Attribute Details

#hide_when_empty ⇒ Object

Whether or not the header should be hidden when the collection is empty. Default is true.



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# File 'lib/table_helper/header.rb', line 15

def hide_when_empty
  @hide_when_empty
end

#row ⇒ Object (readonly)

The actual header row



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# File 'lib/table_helper/header.rb', line 11

def row
  @row
end

#table ⇒ Object (readonly)

The table this header is a part of



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# File 'lib/table_helper/header.rb', line 8

def table
  @table
end

Instance Method Details

#clear ⇒ Object

Clears all of the current columns from the header



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# File 'lib/table_helper/header.rb', line 63

def clear
  row.clear
end

#column(*names) ⇒ Object

Creates one or more to columns in the header. This will clear any pre-existing columns if it is being customized for the first time after it was initially created.



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# File 'lib/table_helper/header.rb', line 70

def column(*names)
  # Clear the header row if this is being customized by the user
  unless @customized
    @customized = true
    clear
  end
  
  # Extract configuration
  options = names.last.is_a?(Hash) ? names.pop : {}
  content = names.last.is_a?(String) ? names.pop : nil
  args = [content, options].compact
  
  names.collect! do |name|
    column = row.cell(name, *args)
    column.content_type = :header
    column[:scope] ||= 'col'
    column
  end
  
  names.length == 1 ? names.first : names
end

#column_names ⇒ Object

Gets the names of all of the columns being displayed in the table



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# File 'lib/table_helper/header.rb', line 58

def column_names
  row.cell_names
end

#columns ⇒ Object

The current columns in this header, in the order in which they will be built



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# File 'lib/table_helper/header.rb', line 53

def columns
  row.cells
end

#html ⇒ Object

Creates and returns the generated html for the header



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# File 'lib/table_helper/header.rb', line 93

def html
  html_options = @html_options.dup
  html_options[:style] = 'display: none;' if table.empty? && hide_when_empty
  
  content_tag(tag_name, content, html_options)
end