class MotionKit::BaseLayout

Abstract base class, responsible for “registration” of layout classes with the class `targets` method.

Very few methods are defined on BaseLayout, and any unknown methods are delegated to the 'apply' method, which accepts a method name, arguments, and an optional block to set the new context.

The TreeLayout subclass defines methods that are appropriate for adding and removing views to a view hierarchy.

Attributes

parent[R]

Public Class Methods

delegate_method_fix(method_name) click to toggle source

Prevents infinite loops when methods that are defined on Object/Kernel are not properly delegated to the target.

# File lib/motion-kit/helpers/base_layout.rb, line 319
def delegate_method_fix(method_name)
  running_name = "motion_kit_is_calling_#{method_name}"
  define_method(method_name) do |*args, &block|
    if target.motion_kit_meta[running_name]
      if block
        apply_with_context(method_name, *args, &block)
      else
        apply_with_target(method_name, *args)
      end
    else
      target.motion_kit_meta[running_name] = true
      retval = apply(method_name, *args, &block)
      target.motion_kit_meta[running_name] = false
      return retval
    end
  end
end
new(args={}) click to toggle source
# File lib/motion-kit/helpers/base_layout.rb, line 19
def initialize(args={})
  # @layout is the object we look in for style methods
  @layout = nil
  # the Layout object that implements custom style methods. Leave this as nil
  # in the initializer.
  @layout_delegate = nil
  @layout_state = :initial
  # You can set a root view by using .new(root: some_view)
  # Explicit roots will not have a strong reference from
  # MotionKit, so retain one yourself from your controller
  # or other view to prevent deallocation.
  @preset_root = args[:root]
end

Public Instance Methods

add_deferred_block(context, &block) click to toggle source

Only intended for private use

# File lib/motion-kit/helpers/base_layout.rb, line 137
def add_deferred_block(context, &block)
  context ||= @context
  if context.nil? && @assign_root
    context ||= self.create_default_root_context
  end
  raise InvalidDeferredError.new('deferred must be run inside of a context') unless context
  raise ArgumentError.new('Block required') unless block

  self.deferred_blocks << [context, block]
end
apply(method_name, *args, &block) click to toggle source

Tries to call the setter (`foo 'value'` => `view.setFoo('value')`), or assignment method (`foo 'value'` => `view.foo = 'value'`), or if a block is given, then the object returned by 'method_name' is assigned as the new context, and the block is executed.

You can call this method directly, but usually it is called via method_missing.

# File lib/motion-kit/helpers/base_layout.rb, line 226
def apply(method_name, *args, &block)
  method_name = method_name.to_s
  raise ApplyError.new("Cannot apply #{method_name.inspect} to instance of #{target.class.name}") if method_name.length == 0

  # if there is no target, than we should raise the NoMethodError; someone
  # called a method on the layout directly.
  begin
    target = self.target
  rescue NoContextError => e
    raise NoMethodError.new("undefined method `#{method_name}' for #{self}:#{self.class}", method_name)
  end

  objc_method_name, objc_method_args = objc_version(method_name, args)
  ruby_method_name, ruby_method_args = ruby_version(method_name, args)

  @layout_delegate ||= Layout.layout_for(target.class)
  if @layout_delegate
    @layout_delegate.set_parent_layout(parent_layout)
    if objc_method_name && @layout_delegate.respond_to?(objc_method_name)
      return @layout_delegate.send(objc_method_name, *objc_method_args, &block)
    elsif @layout_delegate.respond_to?(ruby_method_name)
      return @layout_delegate.send(ruby_method_name, *ruby_method_args, &block)
    end
  end

  if block
    apply_with_context(method_name, *args, &block)
  else
    apply_with_target(method_name, *args, &block)
  end
end
apply_with_context(method_name, *args, &block) click to toggle source
# File lib/motion-kit/helpers/base_layout.rb, line 258
def apply_with_context(method_name, *args, &block)
  objc_method_name, objc_method_args = objc_version(method_name, args)
  ruby_method_name, ruby_method_args = ruby_version(method_name, args)

  if objc_method_name && target.respond_to?(objc_method_name)
    new_context = target.send(objc_method_name, *objc_method_args)
    self.context(new_context, &block)
  elsif target.respond_to?(ruby_method_name)
    new_context = target.send(ruby_method_name, *ruby_method_args)
    self.context(new_context, &block)
  elsif ruby_method_name.include?('_')
    objc_name = MotionKit.objective_c_method_name(ruby_method_name)
    self.apply(objc_name, *args, &block)
  else
    raise ApplyError.new("Cannot apply #{ruby_method_name.inspect} to instance of #{target.class.name}")
  end
end
apply_with_target(method_name, *args, &block) click to toggle source
# File lib/motion-kit/helpers/base_layout.rb, line 276
def apply_with_target(method_name, *args, &block)
  objc_method_name, objc_method_args = objc_version(method_name, args)
  ruby_method_name, ruby_method_args = ruby_version(method_name, args)

  objc_setter = objc_method_name && MotionKit.setter(objc_method_name)
  setter = MotionKit.setter(ruby_method_name)
  assign = "#{ruby_method_name}="

  # The order is important here.
  # - unchanged method name if no args are passed (e.g. `layer`)
  # - setter (`setLayer(val)`)
  # - assign (`layer=val`)
  # - unchanged method name *again*, because many Ruby classes provide a
  #   combined getter/setter (`layer(val)`)
  # - lastly, try again after converting to camelCase
  if objc_method_name && target.respond_to?(objc_method_name)
    target.send(objc_method_name, *objc_method_args, &block)
  elsif args.empty? && target.respond_to?(ruby_method_name)
    target.send(ruby_method_name, *ruby_method_args, &block)
  elsif objc_setter && target.respond_to?(objc_setter)
    target.send(objc_setter, *objc_method_args, &block)
  elsif target.respond_to?(setter)
    target.send(setter, *args, &block)
  elsif target.respond_to?(assign)
    target.send(assign, *args, &block)
  elsif target.respond_to?(ruby_method_name)
    target.send(ruby_method_name, *ruby_method_args, &block)
  # UIAppearance classes are a whole OTHER thing; they never return 'true'
  elsif target.is_a?(MotionKit.appearance_class)
    target.send(setter, *args, &block)
  # Finally, try again with camel case if there's an underscore.
  elsif method_name.include?('_')
    objc_name = MotionKit.objective_c_method_name(method_name)
    self.apply(objc_name, *args, &block)
  else
    target.send(setter, *args, &block)
  end
end
context(new_target) { || ... } click to toggle source

Runs a block of code with a new object as the 'context'. Methods from the Layout classes are applied to this target object, and missing methods are delegated to a new Layout instance that is created based on the new context.

This method is part of the public API, you can pass in any object to have it become the 'context'.

Example:

def table_view_style
  content = target.contentView
  if content
    context(content) do
      background_color UIColor.clearColor
    end
  end

  # usually you use 'context' automatically via method_missing, by
  # passing a block to a method that returns an object. That object becomes
  # the new context.
  layer do
    # target is now a CALayer, and methods are delegated to CALayerHelpers
    corner_radius 5
  end
end
# File lib/motion-kit/helpers/base_layout.rb, line 91
def context(new_target, &block)
  return new_target unless block
  # this little line is incredibly important; the context is only set on
  # the top-level Layout object.

  # mp "MOTIONKIT CONTEXT is #{new_target} meta: #{new_target.motion_kit_meta}"
  return parent_layout.context(new_target, &block) unless is_parent_layout?

  if new_target.is_a?(Symbol)
    new_target = self.get_view(new_target)
  end

  context_was, parent_was, delegate_was = @context, @parent, @layout_delegate

  prev_should_run = @should_run_deferred
  if @should_run_deferred.nil?
    @should_run_deferred = true
  else
    @should_run_deferred = false
  end
  @parent = MK::Parent.new(context_was)
  @context = new_target
  @context.motion_kit_meta[:delegate] ||= Layout.layout_for(@context.class)
  @layout_delegate = @context.motion_kit_meta[:delegate]
  if @layout_delegate
    @layout_delegate.set_parent_layout(parent_layout)
  end
  yield
  @layout_delegate, @context, @parent = delegate_was, context_was, parent_was
  if @should_run_deferred
    run_deferred(new_target)
  end
  @should_run_deferred = prev_should_run

  new_target
end
deferred(context=nil, &block) click to toggle source

Blocks passed to `deferred` are run at the end of a “session”, usually after a call to Layout#layout.

# File lib/motion-kit/helpers/base_layout.rb, line 130
def deferred(context=nil, &block)
  context ||= @context
  parent_layout.add_deferred_block(context, &block)
  return self
end
deferred_blocks() click to toggle source

Only intended for private use

# File lib/motion-kit/helpers/base_layout.rb, line 149
def deferred_blocks
  @deferred_blocks ||= []
end
has_context?() click to toggle source
# File lib/motion-kit/helpers/base_layout.rb, line 45
def has_context?
  if is_parent_layout?
    !!@context
  else
    parent_layout.has_context?
  end
end
ipad?() click to toggle source
# File lib/motion-kit-ios/helpers/layout_device.rb, line 25
def ipad?
  UIDevice.currentDevice.userInterfaceIdiom == UIUserInterfaceIdiomPad
end
iphone35?() click to toggle source
# File lib/motion-kit-ios/helpers/layout_device.rb, line 21
def iphone35?
  iphone? && UIScreen.mainScreen.bounds.size.width == 320 && UIScreen.mainScreen.bounds.size.height == 480
end
iphone47?() click to toggle source
# File lib/motion-kit-ios/helpers/layout_device.rb, line 13
def iphone47?
  iphone? && UIScreen.mainScreen.bounds.size.width == 375 && UIScreen.mainScreen.bounds.size.height == 667
end
iphone4?() click to toggle source
# File lib/motion-kit-ios/helpers/layout_device.rb, line 17
def iphone4?
  iphone? && UIScreen.mainScreen.bounds.size.width == 320 && UIScreen.mainScreen.bounds.size.height == 568
end
iphone55?() click to toggle source
# File lib/motion-kit-ios/helpers/layout_device.rb, line 9
def iphone55?
  iphone? && UIScreen.mainScreen.bounds.size.width == 414 && UIScreen.mainScreen.bounds.size.height == 736
end
iphone?() click to toggle source
# File lib/motion-kit-ios/helpers/layout_device.rb, line 5
def iphone?
  UIDevice.currentDevice.userInterfaceIdiom == UIUserInterfaceIdiomPhone
end
is_parent_layout?() click to toggle source
# File lib/motion-kit/helpers/base_layout.rb, line 41
def is_parent_layout?
  @layout.nil? || @layout == self
end
method_missing(method_name, *args, &block) click to toggle source

@example

def login_button_style
  frame [[0, 0], [100, 20]]
  title 'Login'
end

Methods that style the view start out as missing methods. This just calls 'apply', which searches for the method in the delegate (`@layout_delegate`) or using inspection (`respond_to?(:setFoo)`).

# File lib/motion-kit/helpers/base_layout.rb, line 176
def method_missing(method_name, *args, &block)
  self.apply(method_name, *args, &block)
end
objc_version(method_name, args) click to toggle source
# File lib/motion-kit/helpers/base_layout.rb, line 180
def objc_version(method_name, args)
  if method_name.count(':') > 1
    objc_method_name = method_name
  elsif args.length == 2 && args[1].is_a?(Hash) && !args[1].empty?
    objc_method_name = "#{method_name}:#{args[1].keys.join(':')}:"
  else
    return nil, nil
  end

  if args[1].is_a?(Hash)
    objc_method_args = [args[0]].concat args[1].values
  else
    objc_method_args = args
  end

  return objc_method_name, objc_method_args
end
orientation?(value) click to toggle source

This method is used to check the orientation. On an ipad, this method returns true for :portrait if the device is “upside down”, but it returns false in the same situation on an iphone.

# File lib/motion-kit-ios/helpers/layout_orientation.rb, line 8
def orientation?(value)
  if target.is_a?(UIView) && target.nextResponder && target.nextResponder.is_a?(UIViewController)
    interface_orientation = target.nextResponder.interfaceOrientation
  else
    interface_orientation = UIApplication.sharedApplication.statusBarOrientation
  end

  return case value
  when :portrait
    if ipad?
      interface_orientation == UIInterfaceOrientationPortrait || interface_orientation == UIInterfaceOrientationPortraitUpsideDown
    else
      interface_orientation == UIInterfaceOrientationPortrait
    end
  when :upright, UIInterfaceOrientationPortrait
    interface_orientation == UIInterfaceOrientationPortrait
  when :landscape
    interface_orientation == UIInterfaceOrientationLandscapeLeft || interface_orientation == UIInterfaceOrientationLandscapeRight
  when :landscape_left, UIInterfaceOrientationLandscapeLeft
    interface_orientation == UIInterfaceOrientationLandscapeLeft
  when :landscape_right, UIInterfaceOrientationLandscapeRight
    interface_orientation == UIInterfaceOrientationLandscapeRight
  when :upside_down, UIInterfaceOrientationPortraitUpsideDown
    interface_orientation == UIInterfaceOrientationPortraitUpsideDown
  end
end
orientation_block(orientation, block) click to toggle source
# File lib/motion-kit-ios/helpers/layout_orientation.rb, line 44
def orientation_block(orientation, block)
  block = block.weak!
  always do
    if orientation?(orientation)
      block.call
    end
  end
end
parent_layout() click to toggle source
# File lib/motion-kit/helpers/base_layout.rb, line 37
def parent_layout
  @layout || self
end
retina?() click to toggle source
# File lib/motion-kit-ios/helpers/layout_device.rb, line 29
def retina?
  UIScreen.mainScreen.respond_to?(:scale) && UIScreen.mainScreen.scale == 2
end
ruby_version(method_name, args) click to toggle source
# File lib/motion-kit/helpers/base_layout.rb, line 198
def ruby_version(method_name, args)
  if method_name.count(':') > 1
    parts = method_name.split(':')
    ruby_method_name = parts.first
    if args[1].is_a?(Hash)
      ruby_method_args = args
    else
      keys = parts[1..-1].map(&:to_sym)
      ruby_method_args = [args[0]] << Hash[keys.zip args[1..-1]]
    end
  elsif method_name.count(':') == 1
    ruby_method_name = method_name.split(':').first
    ruby_method_args = args
  else
    ruby_method_name = method_name
    ruby_method_args = args
  end

  return ruby_method_name, ruby_method_args
end
run_deferred(top_level_context) click to toggle source

Only intended for private use

# File lib/motion-kit/helpers/base_layout.rb, line 154
def run_deferred(top_level_context)
  deferred_blocks = self.deferred_blocks
  @deferred_blocks = nil

  deferred_blocks.each do |target, block|
    context(target, &block)
  end

  if @deferred_blocks
    run_deferred(top_level_context)
  end
end
set_parent_layout(layout) click to toggle source
# File lib/motion-kit/helpers/base_layout.rb, line 33
def set_parent_layout(layout)
  @layout = WeakRef.new(layout)
end
target() click to toggle source
# File lib/motion-kit/helpers/base_layout.rb, line 53
def target
  if is_parent_layout?
    # only the "root layout" instance is allowed to change the context.
    # if there isn't a context set, try and create a root instance; this
    # will fail if we're not in a state that allows the root to be created
    @context ||= create_default_root_context
  else
    # child layouts get the context from the root layout
    parent_layout.target
  end
end
tv?() click to toggle source
# File lib/motion-kit-tvos/helpers/layout_device.rb, line 5
def tv?
  UIDevice.currentDevice.userInterfaceIdiom == UIUserInterfaceIdiomTV
end
v() click to toggle source
# File lib/motion-kit/helpers/base_layout.rb, line 64
def v ; target ; end

Protected Instance Methods

preset_root() click to toggle source
# File lib/motion-kit/helpers/base_layout.rb, line 341
def preset_root
  # Set in the initializer
  # TreeLayout.new(root: some_view)
  @preset_root
end