Class: MotionKit::BaseLayout

Inherits:
Object
  • Object
show all
Extended by:
BaseLayoutClassMethods
Defined in:
lib/motion-kit/layouts/base_layout.rb,
lib/motion-kit-ios/layouts/layout_device.rb,
lib/motion-kit-cocoa/layouts/sugarcube_compat.rb,
lib/motion-kit-ios/layouts/layout_orientation.rb,
lib/motion-kit-cocoa/layouts/accessibility_compat.rb

Overview

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.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from BaseLayoutClassMethods

layout_for, memoize, new_child, target_klasses, targets

Constructor Details

#initialize(args = {}) ⇒ BaseLayout

Returns a new instance of BaseLayout.



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# File 'lib/motion-kit/layouts/base_layout.rb', line 19

def initialize(args={})
  # @layout is the object we look in for style methods
  @layout = self
  # 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 = WeakRef.new(args[:root])
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method_name, *args, &block) ⇒ Object

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)`).

Examples:

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


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

def method_missing(method_name, *args, &block)
  self.apply(method_name, *args, &block)
end

Instance Attribute Details

#parent ⇒ Object (readonly)

Returns the value of attribute parent.



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# File 'lib/motion-kit/layouts/base_layout.rb', line 17

def parent
  @parent
end

Class Method Details

.delegate_method_fix(method_name) ⇒ Object

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



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# File 'lib/motion-kit/layouts/base_layout.rb', line 269

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)
      target.motion_kit_meta[running_name] = false
      return retval
    end
  end
end

Instance Method Details

#add_deferred_block(layout, &block) ⇒ Object

Only intended for private use

Raises:



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# File 'lib/motion-kit/layouts/base_layout.rb', line 118

def add_deferred_block(layout, &block)
  raise InvalidDeferredError.new('deferred must be run inside of a context') if @is_top_level.nil?
  raise ArgumentError.new('Block required') unless block

  self.deferred_blocks << [@context, block]

  self
end

#apply(method_name, *args, &block) ⇒ Object

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.

Raises:



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# File 'lib/motion-kit/layouts/base_layout.rb', line 166

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

  if args.length == 2 && args[1].is_a?(Hash) && !args[1].empty?
    long_method_name = "#{method_name}:#{args[1].keys.join(':')}:"
    long_method_args = [args[0]].concat args[1].values
  else
    long_method_name = nil
    long_method_args = nil
  end

  @layout_delegate ||= Layout.layout_for(@layout, target.class)
  if long_method_name && @layout_delegate.respond_to?(long_method_name)
    return @layout_delegate.send(long_method_name, *long_method_args, &block)
  elsif @layout_delegate.respond_to?(method_name)
    return @layout_delegate.send(method_name, *args, &block)
  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) ⇒ Object 



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# File 'lib/motion-kit/layouts/base_layout.rb', line 200

def apply_with_context(method_name, *args, &block)
  if args.length == 2 && args[1].is_a?(Hash) && !args[1].empty?
    long_method_name = "#{method_name}:#{args[1].keys.join(':')}:"
    long_method_args = [args[0]].concat args[1].values
  else
    long_method_name = nil
    long_method_args = nil
  end

  if long_method_name && target.respond_to?(long_method_name)
    new_context = target.send(long_method_name, *long_method_args)
    self.context(new_context, &block)
  elsif target.respond_to?(method_name)
    new_context = target.send(method_name, *args)
    self.context(new_context, &block)
  elsif method_name.include?('_')
    objc_name = MotionKit.objective_c_method_name(method_name)
    self.apply(objc_name, *args, &block)
  else
    raise ApplyError.new("Cannot apply #{method_name.inspect} to instance of #{target.class.name}")
  end
end

#apply_with_target(method_name, *args, &block) ⇒ Object 



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# File 'lib/motion-kit/layouts/base_layout.rb', line 223

def apply_with_target(method_name, *args, &block)
  setter = MotionKit.setter(method_name)
  assign = "#{method_name}="
  if args.length == 2 && args[1].is_a?(Hash) && !args[1].empty?
    long_method_name = "#{method_name}:#{args[1].keys.join(':')}:"
    long_method_args = [args[0]].concat args[1].values
  else
    long_method_name = nil
    long_method_args = nil
  end

  # 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 long_method_name && target.respond_to?(long_method_name)
    target.send(long_method_name, *long_method_args, &block)
  elsif args.empty? && target.respond_to?(method_name)
    target.send(method_name, *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?(method_name)
    target.send(method_name, *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(target, &block) ⇒ Object

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
    # self is now a CALayerLayout instance
    corner_radius 5
  end
end



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# File 'lib/motion-kit/layouts/base_layout.rb', line 75

def context(target, &block)
  return target unless block
  # this little line is incredibly important; the context is only set on
  # the top-level Layout object.
  return @layout.context(target, &block) if @layout != self

  if target.is_a?(Symbol)
    target = self.get(target)
  end

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

  was_top_level = @is_top_level
  if @is_top_level.nil?
    @is_top_level = true
  else
    @is_top_level = false
  end
  @parent = MK::Parent.new(context_was)
  @context = target
  @context.motion_kit_meta[:delegate] ||= Layout.layout_for(@layout, @context.class)
  @layout_delegate = @context.motion_kit_meta[:delegate]
  yield
  @layout_delegate, @context, @parent = delegate_was, context_was, parent_was
  if @is_top_level
    run_deferred(target)
  end
  @is_top_level = was_top_level

  target
end

#deferred(&block) ⇒ Object

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



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# File 'lib/motion-kit/layouts/base_layout.rb', line 109

def deferred(&block)
  if @layout != self
    return @layout.add_deferred_block(self, &block)
  else
    return self.add_deferred_block(self, &block)
  end
end

#deferred_blocks ⇒ Object

Only intended for private use



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# File 'lib/motion-kit/layouts/base_layout.rb', line 128

def deferred_blocks
  @deferred_blocks ||= []
end

#ipad? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/motion-kit-ios/layouts/layout_device.rb', line 17

def ipad?
  UIDevice.currentDevice.userInterfaceIdiom == UIUserInterfaceIdiomPad
end

#iphone35? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/motion-kit-ios/layouts/layout_device.rb', line 13

def iphone35?
  iphone? && UIScreen.mainScreen.bounds.size.width == 320 && UIScreen.mainScreen.bounds.size.height == 480
end

#iphone4? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/motion-kit-ios/layouts/layout_device.rb', line 9

def iphone4?
  iphone? && UIScreen.mainScreen.bounds.size.width == 320 && UIScreen.mainScreen.bounds.size.height == 568
end

#iphone? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/motion-kit-ios/layouts/layout_device.rb', line 5

def iphone?
  UIDevice.currentDevice.userInterfaceIdiom == UIUserInterfaceIdiomPhone
end

#orientation?(value) ⇒ Boolean

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.

Returns:

  • (Boolean) 


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# File 'lib/motion-kit-ios/layouts/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

#retina? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/motion-kit-ios/layouts/layout_device.rb', line 21

def retina?
  UIScreen.mainScreen.respond_to?(:scale) && UIScreen.mainScreen.scale == 2
end

#run_deferred(top_level_context) ⇒ Object

Only intended for private use



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# File 'lib/motion-kit/layouts/base_layout.rb', line 133

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_layout(layout) ⇒ Object 



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# File 'lib/motion-kit/layouts/base_layout.rb', line 33

def set_layout(layout)
  @layout = layout && WeakRef.new(layout)
end

#target ⇒ Object 



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# File 'lib/motion-kit/layouts/base_layout.rb', line 37

def target
  if @layout.nil? || @layout == self
    # 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
    @layout.target
  end
end

#v ⇒ Object 



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# File 'lib/motion-kit/layouts/base_layout.rb', line 48

def v ; target ; end