Class: MotionKit::TreeLayout

Inherits:
BaseLayout show all
Defined in:
lib/motion-kit/layouts/tree_layout.rb

Overview

A sensible parent class for any Tree-like layout class. Platform agnostic. Any platform-specific tasks are offloaded to child elements (add_child, remove_child). You could use a TreeLayout subclass to construct a hierarchy representing a family tree, for instance. But that would be a silly use of MotionKit.

Direct Known Subclasses

CALayerLayout, Layout, MenuLayout, WindowLayout

Instance Attribute Summary

Attributes inherited from BaseLayout

#parent

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from BaseLayout

#add_deferred_block, #apply, #apply_with_context, #apply_with_target, #context, #deferred, #deferred_blocks, delegate_method_fix, #initialize, #ipad?, #iphone35?, #iphone4?, #iphone?, method_added, #method_missing, #orientation?, overridden_methods, override_start, override_stop, overrides, #retina?, #set_layout, #target, #v

Methods included from BaseLayoutClassMethods

#layout_for, #memoize, #new_child, #target_klasses, #targets

Constructor Details

This class inherits a constructor from MotionKit::BaseLayout

Dynamic Method Handling

This class handles dynamic methods through the method_missing method in the class MotionKit::BaseLayout

Class Method Details

.view(name) ⇒ Object

This is an ‘attr_reader`-like method that also calls `build_view` if the assigned to ivars in your `layout` method.

Examples:

class MyLayout < MK::Layout
  view :label
  view :login_button

  def layout
    # if element id and attr name match, no need to assign to ivar
    add UILabel, :label
    # if they don't match you must assign.  If you are using
    # Key-Value observation you should use the setter:
    self. = add UIButton, :button
  end

end


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# File 'lib/motion-kit/layouts/tree_layout.rb', line 31

def view(name)
  ivar_name = "@#{name}"
  define_method(name) do
    unless instance_variable_get(ivar_name)
      view = self.get(name)
      unless view
        build_view unless @view
        view = instance_variable_get(ivar_name) || self.get(name)
      end
      self.send("#{name}=", view)
      return view
    end
    return instance_variable_get(ivar_name)
  end
  # KVO compliance
  attr_writer name
end

Instance Method Details

#add(element, element_id = nil, &block) ⇒ Object

Instantiates a view via ‘create` and adds the view to the current target. If no view exists on the stack, a default root view can be created if that has been enabled. The block is run in the context of the new view.



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# File 'lib/motion-kit/layouts/tree_layout.rb', line 167

def add(element, element_id=nil, &block)
  # make sure we have a target - raises NoContextError if none exists
  self.target

  element = initialize_view(element)
  unless @context
    create_default_root_context
  end
  self.apply(:add_child, element)
  create(element, element_id)

  if block
    context(element, &block)
  end

  element
end

#all(element_id, in: root) ⇒ Object

Same as ‘all`, but with the root view specified.



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# File 'lib/motion-kit/layouts/tree_layout.rb', line 218

def all(element_id)
  if @layout != self
    return @layout.all(element_id)
  end
  self.all(element_id, in: self.view)
end

#call_style_method(element, element_id) ⇒ Object 



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# File 'lib/motion-kit/layouts/tree_layout.rb', line 123

def call_style_method(element, element_id)
  style_method = "#{element_id}_style"
  if @layout.respond_to?(style_method)
    @layout.context(element) do
      @layout.send(style_method)
    end
  end
  return element
end

#create(element, element_id = nil, &block) ⇒ Object

instantiates a view, possibly running a ‘layout block’ to add child views.



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# File 'lib/motion-kit/layouts/tree_layout.rb', line 106

def create(element, element_id=nil, &block)
  element = initialize_view(element)

  if element_id
    # We set the optional id and call the '_style' method, if it's been
    # defined.
    element.motion_kit_id = element_id
    self.call_style_method(element, element_id)
  end

  if block
    context(element, &block)
  end

  element
end

#create_default_root_context ⇒ Object 



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# File 'lib/motion-kit/layouts/tree_layout.rb', line 261

def create_default_root_context
  if @assign_root
    # Originally I thought default_root should be `apply`ied like other
    # view-related methods, but actually this method *only* gets called
    # from within the `layout` method, and so should already be inside the
    # correct Layout subclass.
    @context = root(default_root)
  else
    raise NoContextError.new("No top level view specified (missing outer 'create' method?)")
  end
end

#first(element_id, in: root) ⇒ Object 



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# File 'lib/motion-kit/layouts/tree_layout.rb', line 194

def first(element_id) ; get(element_id) ; end

#get(element_id, in: root) ⇒ Object

Same as ‘get`, but with the root view specified.



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# File 'lib/motion-kit/layouts/tree_layout.rb', line 188

def get(element_id)
  if @layout != self
    return @layout.get(element_id)
  end
  self.get(element_id, in: self.view)
end

#initial(&block) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/motion-kit/layouts/tree_layout.rb', line 155

def initial(&block)
  raise ArgumentError.new('Block required') unless block

  if @layout_state == :initial
    yield
  end
  return self
end

#last(element_id, in: root) ⇒ Object

Same as ‘last`, but with the root view specified.



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# File 'lib/motion-kit/layouts/tree_layout.rb', line 205

def last(element_id)
  if @layout != self
    return @layout.last(element_id)
  end
  self.last(element_id, in: self.view)
end

#nth(element_id, at: index, in: root) ⇒ Object

Same as ‘nth`, but with the root view specified.



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# File 'lib/motion-kit/layouts/tree_layout.rb', line 231

def nth(element_id, index)
  if @layout != self
    return @layout.nth(element_id, index)
  end
  self.all(element_id, in: self.view)[index]
end

#reapply(&block) ⇒ Object

Calls the style method of all objects in the view hierarchy

Raises:

  • (ArgumentError) 


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# File 'lib/motion-kit/layouts/tree_layout.rb', line 146

def reapply(&block)
  raise ArgumentError.new('Block required') unless block

  if @layout_state == :reapply
    yield
  end
  return self
end

#reapply!(root = nil) ⇒ Object

Calls the style method of all objects in the view hierarchy



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# File 'lib/motion-kit/layouts/tree_layout.rb', line 134

def reapply!(root=nil)
  root ||= self.view
  @layout_state = :reapply
  MotionKit.find_all_views(root) do |view|
    call_style_method(view, view.motion_kit_id) if view.motion_kit_id
  end
  @layout_state = :initial

  return self
end

#remove(element_id, from: root) ⇒ Object

Same as ‘remove`, but with the root view specified.



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# File 'lib/motion-kit/layouts/tree_layout.rb', line 245

def remove(element_id)
  if @layout != self
    return @layout.remove(element_id)
  end
  self.remove(element_id, from: self.view)
end

#root(element, element_id = nil, &block) ⇒ Object

Assign a view to act as the ‘root’ view for this layout. This method can only be called once, and must be called before ‘add` is called for the first time (otherwise `add` will create a default root view). This method must be called from inside `layout`, otherwise you should just use `create`.

You can also call this method with just an element_id, and the default root view will be created.



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# File 'lib/motion-kit/layouts/tree_layout.rb', line 67

def root(element, element_id=nil, &block)
  if @view
    raise ContextConflictError.new("Already created the root view")
  end
  unless @assign_root
    raise InvalidRootError.new("You should only create a 'root' view from inside the 'layout' method (use 'create' elsewhere)")
  end
  @assign_root = false

  # this method can be called with just a symbol, to assign the root element_id
  if element.is_a?(Symbol)
    element_id = element
    # See note below about why we don't need to `apply(:default_root)`
    element = preset_root || default_root
  elsif @preset_root
    # You're trying to make two roots, one at initialization
    # and one in your layout itself.
    raise ContextConflictError.new("Already created the root view")
  end

  @view = initialize_view(element)
  if block
    if @context
      raise ContextConflictError.new("Already in a context")
    end

    context(@view) do
      # We're just using the `create` method for its side effects: calling the
      # style method and calling the block.
      create(@view, element_id, &block)
    end
  elsif element_id
    create(@view, element_id)
  end

  return @view
end

#view ⇒ Object

The main view. This method builds the layout and returns the root view.



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# File 'lib/motion-kit/layouts/tree_layout.rb', line 52

def view
  if @layout != self
    return @layout.view
  end
  @view ||= build_view
end