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

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.



19
20
21
22
23
24
25
26
27
28
 
# 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)
  @preset_root = 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


152
153
154
 
# File 'lib/motion-kit/layouts/base_layout.rb', line 152

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.



17
18
19
 
# 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.



283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
 
# File 'lib/motion-kit/layouts/base_layout.rb', line 283

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

.method_added(method_name) ⇒ Object

this last little “catch-all” method is helpful to warn against methods that are defined already. Since magic methods are so important, this warning can come in handy.



304
305
306
307
308
309
310
311
312
313
314
 
# File 'lib/motion-kit/layouts/base_layout.rb', line 304

def method_added(method_name)
  return if @allow_all_override

  if self < BaseLayout && BaseLayout.method_defined?(method_name)
    if overridden_methods.include?(method_name)
      overridden_methods.delete(method_name)
    else
      NSLog("Warning! The method #{self.name}##{method_name} has already been defined on MotionKit::BaseLayout or one of its ancestors.")
    end
  end
end

.overridden_methods ⇒ Object 



277
278
279
 
# File 'lib/motion-kit/layouts/base_layout.rb', line 277

def overridden_methods
  @overridden_methods ||= []
end

.override_start ⇒ Object 



265
266
267
 
# File 'lib/motion-kit/layouts/base_layout.rb', line 265

def override_start
  @allow_all_override = true
end

.override_stop ⇒ Object 



269
270
271
 
# File 'lib/motion-kit/layouts/base_layout.rb', line 269

def override_stop
  @allow_all_override = false
end

.overrides(method_name) ⇒ Object 



273
274
275
 
# File 'lib/motion-kit/layouts/base_layout.rb', line 273

def overrides(method_name)
  overridden_methods << method_name
end

Instance Method Details

#add_deferred_block(layout, &block) ⇒ Object

Only intended for private use

Raises:



115
116
117
118
119
120
121
122
 
# File 'lib/motion-kit/layouts/base_layout.rb', line 115

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:



163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
 
# File 'lib/motion-kit/layouts/base_layout.rb', line 163

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 



197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
 
# File 'lib/motion-kit/layouts/base_layout.rb', line 197

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 



220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
 
# File 'lib/motion-kit/layouts/base_layout.rb', line 220

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)
  else
    target.send(setter, *args, &block)
    # raise ApplyError.new("Cannot apply #{method_name.inspect} to instance of #{target.class.name} (from #{@layout_delegate && @layout_delegate.class})")
  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



72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
 
# File 'lib/motion-kit/layouts/base_layout.rb', line 72

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.



106
107
108
109
110
111
112
 
# File 'lib/motion-kit/layouts/base_layout.rb', line 106

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



125
126
127
 
# File 'lib/motion-kit/layouts/base_layout.rb', line 125

def deferred_blocks
  @deferred_blocks ||= []
end

#ipad? ⇒ Boolean

Returns:

  • (Boolean) 


17
18
19
 
# File 'lib/motion-kit-ios/layouts/layout_device.rb', line 17

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

#iphone35? ⇒ Boolean

Returns:

  • (Boolean) 


13
14
15
 
# 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) 


9
10
11
 
# 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) 


5
6
7
 
# 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) 


8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
 
# 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) 


21
22
23
 
# 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



130
131
132
133
134
135
136
137
138
139
140
141
 
# File 'lib/motion-kit/layouts/base_layout.rb', line 130

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 



30
31
32
 
# File 'lib/motion-kit/layouts/base_layout.rb', line 30

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

#target ⇒ Object 



34
35
36
37
38
39
40
41
42
43
44
 
# File 'lib/motion-kit/layouts/base_layout.rb', line 34

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 



45
 
# File 'lib/motion-kit/layouts/base_layout.rb', line 45

def v ; target ; end