zrzka/autolayout.py

## autolayout.py
#!python3

import ui
from objc_util import ObjCInstance, ObjCClass, on_main_thread
from enum import Enum
from functools import partial
from collections import defaultdict


_LayoutConstraint = ObjCClass('NSLayoutConstraint')


class LayoutRelation(int, Enum):
    lessThanOrEqual = -1
    equal = 0
    greaterThanOrEqual = 1


class LayoutAttribute(int, Enum):
    notAnAttribute = 0
    left = 1
    right = 2
    top = 3
    bottom = 4
    leading = 5
    trailing = 6
    width = 7
    height = 8
    centerX = 9
    centerY = 10
    baseline = 11
    lastBaseline = 12
    firstBaseline = 13
    leftMargin = 14
    rightMargin = 15
    topMargin = 16
    bottomMargin = 17
    leadingMargin = 18
    trailingMargin = 19
    centerXWithinMargins = 20
    centerYWithinMargins = 21


class LayoutConstraintOrientation(int, Enum):
    horizontal = 0
    vertical = 1


class LayoutPriority(float, Enum):
    required = 1000
    defaultHight = 750
    defaultLow = 250
    fittingSizeLevel = 50


class _LayoutBaseAttribute:
    _relations = {
        "min": LayoutRelation.greaterThanOrEqual,
        "max": LayoutRelation.lessThanOrEqual,
        "equal": LayoutRelation.equal
    }

    def __init__(self, view, attribute, other=None, other_attribute=LayoutAttribute.notAnAttribute):
        assert(isinstance(view, LayoutView))
        assert(isinstance(attribute, LayoutAttribute))

        self._view = view
        self._attribute = attribute
        self._constraints = {}

        if other:
            assert(isinstance(other, ui.View))
            assert(isinstance(other_attribute, LayoutAttribute))

            self._other = other
            self._other_attribute = other_attribute
        else:
            self._other = None
            self._other_attribute = LayoutAttribute.notAnAttribute

    @property
    def view(self):
        return self._view

    @property
    def attribute(self):
        return self._attribute

    @property
    def other(self):
        return self._other

    @property
    def other_attribute(self):
        return self._other_attribute

    @property
    def superview(self):
        return self._view.superview

    @on_main_thread
    def remove_constraint(self, constraint):
        ObjCInstance(self.superview).removeConstraint_(constraint)

    @on_main_thread
    def add_constraint(self, constraint):
        ObjCInstance(self.superview).addConstraint_(constraint)

    def constraint(relation, value, priority):
        raise NotImplementedError

    def __setattr__(self, name, value):
        if name in self._relations.keys():
            constraint = self._constraints.get(name, None)
            if constraint:
                self.remove_constraint(constraint)

            if value is None:
                return

            if isinstance(value, tuple):
                priority = value[1]
                value = value[0]
            else:
                priority = LayoutPriority.required

            constraint = self.constraint(self._relations[name], value, priority)
            self._constraints[name] = constraint
            self.add_constraint(constraint)
        else:
            super().__setattr__(name, value)


class _LayoutConstantAttribute(_LayoutBaseAttribute):
    def __init__(self, view, attribute, other=None, other_attribute=LayoutAttribute.notAnAttribute):
        super().__init__(view, attribute, other, other_attribute)

    def constraint(self, relation, value, priority):
        constraint = _LayoutConstraint.constraintWithItem_attribute_relatedBy_toItem_attribute_multiplier_constant_(
            self.view, int(self.attribute), int(relation), self.other, int(self.other_attribute), 1.0, value
        )
        constraint.setPriority_(priority)
        return constraint


class _LayoutMultiplierAttribute(_LayoutBaseAttribute):
    def __init__(self, view, attribute, other=None, other_attribute=LayoutAttribute.notAnAttribute):
        super().__init__(view, attribute, other, other_attribute)

    def constraint(self, relation, value, priority):
        constraint = _LayoutConstraint.constraintWithItem_attribute_relatedBy_toItem_attribute_multiplier_constant_(
            self.view, int(self.attribute), int(relation), self.other, int(self.other_attribute), value, 0
        )
        constraint.setPriority_(priority)
        return constraint


class Layout:
    _definitions = {
        "width": (_LayoutConstantAttribute, LayoutAttribute.width, LayoutAttribute.notAnAttribute),
        "height": (_LayoutConstantAttribute, LayoutAttribute.height, LayoutAttribute.notAnAttribute),

        "align_center_x_to": (_LayoutConstantAttribute, LayoutAttribute.centerX, LayoutAttribute.centerX),
        "align_center_y_to": (_LayoutConstantAttribute, LayoutAttribute.centerY, LayoutAttribute.centerY),
        "align_leading_to": (_LayoutConstantAttribute, LayoutAttribute.leading, LayoutAttribute.leading),
        "align_trailing_to": (_LayoutConstantAttribute, LayoutAttribute.trailing, LayoutAttribute.trailing),
        "align_top_to": (_LayoutConstantAttribute, LayoutAttribute.top, LayoutAttribute.top),
        "align_bottom_to": (_LayoutConstantAttribute, LayoutAttribute.bottom, LayoutAttribute.bottom),
        "align_left_to": (_LayoutConstantAttribute, LayoutAttribute.left, LayoutAttribute.left),
        "align_right_to": (_LayoutConstantAttribute, LayoutAttribute.right, LayoutAttribute.right),
        "align_baseline_to": (_LayoutConstantAttribute, LayoutAttribute.baseline, LayoutAttribute.baseline),

        "align_center_x_with_superview": (_LayoutConstantAttribute, LayoutAttribute.centerX, LayoutAttribute.centerX),
        "align_center_y_with_superview": (_LayoutConstantAttribute, LayoutAttribute.centerY, LayoutAttribute.centerY),
        "align_leading_with_superview": (_LayoutConstantAttribute, LayoutAttribute.leading, LayoutAttribute.leading),
        "align_trailing_with_superview": (_LayoutConstantAttribute, LayoutAttribute.trailing, LayoutAttribute.trailing),
        "align_top_with_superview": (_LayoutConstantAttribute, LayoutAttribute.top, LayoutAttribute.top),
        "align_bottom_with_superview": (_LayoutConstantAttribute, LayoutAttribute.bottom, LayoutAttribute.bottom),
        "align_left_with_superview": (_LayoutConstantAttribute, LayoutAttribute.left, LayoutAttribute.left),
        "align_right_with_superview": (_LayoutConstantAttribute, LayoutAttribute.right, LayoutAttribute.right),

        "relative_superview_width": (_LayoutMultiplierAttribute, LayoutAttribute.width, LayoutAttribute.width),
        "relative_superview_height": (_LayoutMultiplierAttribute, LayoutAttribute.height, LayoutAttribute.height),

        "relative_width_to": (_LayoutMultiplierAttribute, LayoutAttribute.width, LayoutAttribute.width),
        "relative_height_to": (_LayoutMultiplierAttribute, LayoutAttribute.height, LayoutAttribute.height),

        "left_offset_to": (_LayoutConstantAttribute, LayoutAttribute.left, LayoutAttribute.right),
        "right_offset_to": (_LayoutConstantAttribute, LayoutAttribute.right, LayoutAttribute.left),
        "top_offset_to": (_LayoutConstantAttribute, LayoutAttribute.top, LayoutAttribute.bottom),
        "bottom_offset_to": (_LayoutConstantAttribute, LayoutAttribute.bottom, LayoutAttribute.top),
        "leading_offset_to": (_LayoutConstantAttribute, LayoutAttribute.leading, LayoutAttribute.trailing),
        "trailing_offset_to": (_LayoutConstantAttribute, LayoutAttribute.trailing, LayoutAttribute.leading)
    }

    def __init__(self, view):
        assert(isinstance(view, LayoutView))

        self._view = view
        self._attributes = {}

    def _create_attribute(self, cls, attribute, other_attribute, other):
        assert(isinstance(attribute, LayoutAttribute))
        if other:
            assert(isinstance(other_attribute, LayoutAttribute))
            assert(isinstance(other, ui.View))

        name = '{}{}{}'.format(int(attribute), id(other), int(other_attribute))

        layout_attribute = self._attributes.get(name, None)
        if layout_attribute:
            return layout_attribute

        layout_attribute = cls(self._view, attribute, other, other_attribute)
        self._attributes[name] = layout_attribute
        return layout_attribute

    def _attribute(self, name, definition):
        cls = definition[0]
        attribute = definition[1]
        other_attribute = definition[2]

        assert(isinstance(attribute, LayoutAttribute))
        assert(isinstance(other_attribute, LayoutAttribute))

        if 'superview' in name:
            return self._create_attribute(cls, attribute, other_attribute, self._view.superview)
        elif name.endswith('_to'):
            return partial(self._create_attribute, cls, attribute, other_attribute)
        else:
            assert(other_attribute is LayoutAttribute.notAnAttribute)
            return self._create_attribute(cls, attribute, other_attribute, None)

    def __getattr__(self, name):
        if name in self._definitions:
            return self._attribute(name, self._definitions[name])

        return super().__getattr__(name)


class LayoutView(ui.View):
    def __init__(self, view):
        assert(isinstance(view, ui.View))

        self._view = view
        self.add_subview(self._view)

        self._view_objc = ObjCInstance(self._view)
        self._objc = ObjCInstance(self)

        self._view_objc.setTranslatesAutoresizingMaskIntoConstraints_(False)
        self._objc.setTranslatesAutoresizingMaskIntoConstraints_(False)

        attributes = [LayoutAttribute.left, LayoutAttribute.right, LayoutAttribute.top, LayoutAttribute.bottom]
        for attribute in attributes:
            constraint = _LayoutConstraint.constraintWithItem_attribute_relatedBy_toItem_attribute_multiplier_constant_(
                self._view_objc, int(attribute), int(LayoutRelation.equal), self._objc, int(attribute), 1.0, 0
            )
            self._objc.addConstraint_(constraint)

        self._layout = None

    @property
    def layout(self):
        if not self._layout:
            self._layout = Layout(self)

        return self._layout

    @property
    def view(self):
        return self._view


def table_like():
    view = ui.View(background_color='white')

    name_label = LayoutView(ui.Label(
        text='Name', font=('<system-bold>', 18), background_color=(0, 0, 0, 0.1)
    ))
    view.add_subview(name_label)

    # 15 points from superview left edge
    name_label.layout.align_left_with_superview.equal = 15
    # 15 points from superview top edge
    name_label.layout.align_top_with_superview.equal = 15

    age_label = LayoutView(ui.Label(
        text='Age', font=('<system-bold>', 18),
        alignment=ui.ALIGN_RIGHT, background_color=(0, 0, 0, 0.1)
    ))
    view.add_subview(age_label)

    # Align label baseline with name label
    age_label.layout.align_baseline_to(name_label).equal = 0
    # Right side of age label is 15 points from superview right edge
    age_label.layout.align_right_with_superview.equal = -15
    # Age label width is always 150 pixel
    age_label.layout.width.equal = (150, LayoutPriority.required)

    age_label.layout.leading_offset_to(name_label).equal = 8

    last_name_label = name_label
    last_age_label = age_label

    for i in range(1, 5):
        name_label = LayoutView(ui.Label(
            text='Dummy Name {}'.format(i), background_color=(0, 0, 0, 0.01)
        ))
        view.add_subview(name_label)

        # Left egde aligned with left egde of last label
        name_label.layout.align_leading_to(last_name_label).equal = 0
        # Top edge aligned with bottom edge of last label + 16 points
        name_label.layout.top_offset_to(last_name_label).equal = 16
        # Width is 100% of last name label width
        name_label.layout.relative_width_to(last_name_label).equal = 1.0

        age_label = LayoutView(ui.Label(
            text=str(i * 5), alignment=ui.ALIGN_RIGHT, background_color=(0, 0, 0, 0.01)
        ))
        view.add_subview(age_label)

        # Baseline aligned with name label
        age_label.layout.align_baseline_to(name_label).equal = 0
        # Right edge aligned with last age label
        age_label.layout.align_trailing_to(last_age_label).equal = 0
        # Width is 100% of width of last age label
        age_label.layout.relative_width_to(last_age_label).equal = 1.0

        last_name_label = name_label
        last_age_label = age_label

    return view


def center_in_superview():
    view = ui.View(background_color='white')

    label = LayoutView(ui.Label(
        text='80% of width, height, centered', alignment=ui.ALIGN_CENTER,
        background_color=(0, 0, 0, 0.1)
    ))
    view.add_subview(label)

    # Align horizontal, vertical center with superview
    label.layout.align_center_x_with_superview.equal = 0
    label.layout.align_center_y_with_superview.equal = 0

    # Width and height 80% of superview width and height
    label.layout.relative_width_to(view).equal = 0.8
    label.layout.relative_height_to(view).equal = 0.8

    return view


def grid_like():
    view = ui.View(background_color='white')

    rows = 3
    cols = 3
    spacing = 10

    cells = defaultdict(list)

    for row in range(0, rows):
        for col in range(0, cols):
            cell = LayoutView(ui.Label(
                text='R: {} C: {}'.format(row, col),
                alignment=ui.ALIGN_CENTER,
                background_color=(0, 0, 0, 0.1)
            ))
            view.add_subview(cell)
            cells[row].append(cell)

            if row == 0:
                # Top cells, align to superview top
                cell.layout.align_top_to(view).equal = spacing

            if row == rows - 1:
                # Bottom cells, align to superview bottom
                cell.layout.align_bottom_to(view).equal = -spacing

            if col == 0:
                # Left column cells, align to superview left
                cell.layout.align_left_to(view).equal = spacing

            if col == cols - 1:
                # Right column cells, align to superview right
                cell.layout.align_right_to(view).equal = -spacing

            if row > 0 or col > 0:
                # Not top/left cell, make same width / height as top/left cell
                cell.layout.relative_width_to(cells[0][0]).equal = 1.0
                cell.layout.relative_height_to(cells[0][0]).equal = 1.0

            if col > 0:
                # Not first column, add spacing between cells
                cell.layout.left_offset_to(cells[row][col - 1]).equal = spacing

            if row > 0:
                # Not first row, add spacing between cells
                cell.layout.top_offset_to(cells[row - 1][col]).equal = spacing

    return view


def breadcrumb():
    view = ui.View(background_color='white')

    spacing = 8
    previous_label = None

    for title in ('Documents', 'blackmamba', 'experimental', '__init__.py'):
        label = LayoutView(ui.Label(
            text=title,
            background_color=(0, 0, 0, 0.1)
        ))
        view.add_subview(label)

        if previous_label:
            label.layout.align_baseline_to(previous_label).equal = 0
            label.layout.leading_offset_to(previous_label).equal = spacing
        else:
            label.layout.align_top_to(view).equal = spacing
            label.layout.align_left_to(view).equal = spacing

        previous_label = label

    return view


def main():
    datasource = ui.ListDataSource([
        {
            'title': 'Table',
            'view': table_like
        },
        {
            'title': 'Center in superview',
            'view': center_in_superview
        },
        {
            'title': 'Grid',
            'view': grid_like
        },
        {
            'title': 'Breadcrumb',
            'view': breadcrumb
        }
    ])

    def did_select(ds):
        nv = ds.tableview.navigation_view

        tv_objc = ObjCInstance(ds.tableview)
        index_path = tv_objc.indexPathForSelectedRow()
        if index_path:
            tv_objc.deselectRowAtIndexPath_animated_(index_path, True)

        row = ds.selected_row
        if row < 0:
            return

        item = ds.items[row]

        view = item['view']()
        view.name = item['title']
        nv.push_view(view)

    datasource.action = did_select

    window_size = ui.get_window_size()
    view = ui.View(width=window_size[0] * 0.8, height=window_size[1] * 0.8)

    tv = ui.TableView(frame=view.bounds, flex='WH')
    tv.name = 'Auto Layout Demo'
    tv.data_source = datasource
    tv.delegate = datasource

    nv = ui.NavigationView(tv, frame=view.bounds, flex='WH')
    view.add_subview(nv)
    view.present('sheet')


if __name__ == '__main__':
    main()
	#!python3

	import ui
	from objc_util import ObjCInstance, ObjCClass, on_main_thread
	from enum import Enum
	from functools import partial
	from collections import defaultdict


	_LayoutConstraint = ObjCClass('NSLayoutConstraint')


	class LayoutRelation(int, Enum):
	lessThanOrEqual = -1
	equal = 0
	greaterThanOrEqual = 1


	class LayoutAttribute(int, Enum):
	notAnAttribute = 0
	left = 1
	right = 2
	top = 3
	bottom = 4
	leading = 5
	trailing = 6
	width = 7
	height = 8
	centerX = 9
	centerY = 10
	baseline = 11
	lastBaseline = 12
	firstBaseline = 13
	leftMargin = 14
	rightMargin = 15
	topMargin = 16
	bottomMargin = 17
	leadingMargin = 18
	trailingMargin = 19
	centerXWithinMargins = 20
	centerYWithinMargins = 21


	class LayoutConstraintOrientation(int, Enum):
	horizontal = 0
	vertical = 1


	class LayoutPriority(float, Enum):
	required = 1000
	defaultHight = 750
	defaultLow = 250
	fittingSizeLevel = 50


	class _LayoutBaseAttribute:
	_relations = {
	"min": LayoutRelation.greaterThanOrEqual,
	"max": LayoutRelation.lessThanOrEqual,
	"equal": LayoutRelation.equal
	}

	def __init__(self, view, attribute, other=None, other_attribute=LayoutAttribute.notAnAttribute):
	assert(isinstance(view, LayoutView))
	assert(isinstance(attribute, LayoutAttribute))

	self._view = view
	self._attribute = attribute
	self._constraints = {}

	if other:
	assert(isinstance(other, ui.View))
	assert(isinstance(other_attribute, LayoutAttribute))

	self._other = other
	self._other_attribute = other_attribute
	else:
	self._other = None
	self._other_attribute = LayoutAttribute.notAnAttribute

	@property
	def view(self):
	return self._view

	@property
	def attribute(self):
	return self._attribute

	@property
	def other(self):
	return self._other

	@property
	def other_attribute(self):
	return self._other_attribute

	@property
	def superview(self):
	return self._view.superview

	@on_main_thread
	def remove_constraint(self, constraint):
	ObjCInstance(self.superview).removeConstraint_(constraint)

	@on_main_thread
	def add_constraint(self, constraint):
	ObjCInstance(self.superview).addConstraint_(constraint)

	def constraint(relation, value, priority):
	raise NotImplementedError

	def __setattr__(self, name, value):
	if name in self._relations.keys():
	constraint = self._constraints.get(name, None)
	if constraint:
	self.remove_constraint(constraint)

	if value is None:
	return

	if isinstance(value, tuple):
	priority = value[1]
	value = value[0]
	else:
	priority = LayoutPriority.required

	constraint = self.constraint(self._relations[name], value, priority)
	self._constraints[name] = constraint
	self.add_constraint(constraint)
	else:
	super().__setattr__(name, value)


	class _LayoutConstantAttribute(_LayoutBaseAttribute):
	def __init__(self, view, attribute, other=None, other_attribute=LayoutAttribute.notAnAttribute):
	super().__init__(view, attribute, other, other_attribute)

	def constraint(self, relation, value, priority):
	constraint = _LayoutConstraint.constraintWithItem_attribute_relatedBy_toItem_attribute_multiplier_constant_(
	self.view, int(self.attribute), int(relation), self.other, int(self.other_attribute), 1.0, value
	)
	constraint.setPriority_(priority)
	return constraint


	class _LayoutMultiplierAttribute(_LayoutBaseAttribute):
	def __init__(self, view, attribute, other=None, other_attribute=LayoutAttribute.notAnAttribute):
	super().__init__(view, attribute, other, other_attribute)

	def constraint(self, relation, value, priority):
	constraint = _LayoutConstraint.constraintWithItem_attribute_relatedBy_toItem_attribute_multiplier_constant_(
	self.view, int(self.attribute), int(relation), self.other, int(self.other_attribute), value, 0
	)
	constraint.setPriority_(priority)
	return constraint


	class Layout:
	_definitions = {
	"width": (_LayoutConstantAttribute, LayoutAttribute.width, LayoutAttribute.notAnAttribute),
	"height": (_LayoutConstantAttribute, LayoutAttribute.height, LayoutAttribute.notAnAttribute),

	"align_center_x_to": (_LayoutConstantAttribute, LayoutAttribute.centerX, LayoutAttribute.centerX),
	"align_center_y_to": (_LayoutConstantAttribute, LayoutAttribute.centerY, LayoutAttribute.centerY),
	"align_leading_to": (_LayoutConstantAttribute, LayoutAttribute.leading, LayoutAttribute.leading),
	"align_trailing_to": (_LayoutConstantAttribute, LayoutAttribute.trailing, LayoutAttribute.trailing),
	"align_top_to": (_LayoutConstantAttribute, LayoutAttribute.top, LayoutAttribute.top),
	"align_bottom_to": (_LayoutConstantAttribute, LayoutAttribute.bottom, LayoutAttribute.bottom),
	"align_left_to": (_LayoutConstantAttribute, LayoutAttribute.left, LayoutAttribute.left),
	"align_right_to": (_LayoutConstantAttribute, LayoutAttribute.right, LayoutAttribute.right),
	"align_baseline_to": (_LayoutConstantAttribute, LayoutAttribute.baseline, LayoutAttribute.baseline),

	"align_center_x_with_superview": (_LayoutConstantAttribute, LayoutAttribute.centerX, LayoutAttribute.centerX),
	"align_center_y_with_superview": (_LayoutConstantAttribute, LayoutAttribute.centerY, LayoutAttribute.centerY),
	"align_leading_with_superview": (_LayoutConstantAttribute, LayoutAttribute.leading, LayoutAttribute.leading),
	"align_trailing_with_superview": (_LayoutConstantAttribute, LayoutAttribute.trailing, LayoutAttribute.trailing),
	"align_top_with_superview": (_LayoutConstantAttribute, LayoutAttribute.top, LayoutAttribute.top),
	"align_bottom_with_superview": (_LayoutConstantAttribute, LayoutAttribute.bottom, LayoutAttribute.bottom),
	"align_left_with_superview": (_LayoutConstantAttribute, LayoutAttribute.left, LayoutAttribute.left),
	"align_right_with_superview": (_LayoutConstantAttribute, LayoutAttribute.right, LayoutAttribute.right),

	"relative_superview_width": (_LayoutMultiplierAttribute, LayoutAttribute.width, LayoutAttribute.width),
	"relative_superview_height": (_LayoutMultiplierAttribute, LayoutAttribute.height, LayoutAttribute.height),

	"relative_width_to": (_LayoutMultiplierAttribute, LayoutAttribute.width, LayoutAttribute.width),
	"relative_height_to": (_LayoutMultiplierAttribute, LayoutAttribute.height, LayoutAttribute.height),

	"left_offset_to": (_LayoutConstantAttribute, LayoutAttribute.left, LayoutAttribute.right),
	"right_offset_to": (_LayoutConstantAttribute, LayoutAttribute.right, LayoutAttribute.left),
	"top_offset_to": (_LayoutConstantAttribute, LayoutAttribute.top, LayoutAttribute.bottom),
	"bottom_offset_to": (_LayoutConstantAttribute, LayoutAttribute.bottom, LayoutAttribute.top),
	"leading_offset_to": (_LayoutConstantAttribute, LayoutAttribute.leading, LayoutAttribute.trailing),
	"trailing_offset_to": (_LayoutConstantAttribute, LayoutAttribute.trailing, LayoutAttribute.leading)
	}

	def __init__(self, view):
	assert(isinstance(view, LayoutView))

	self._view = view
	self._attributes = {}

	def _create_attribute(self, cls, attribute, other_attribute, other):
	assert(isinstance(attribute, LayoutAttribute))
	if other:
	assert(isinstance(other_attribute, LayoutAttribute))
	assert(isinstance(other, ui.View))

	name = '{}{}{}'.format(int(attribute), id(other), int(other_attribute))

	layout_attribute = self._attributes.get(name, None)
	if layout_attribute:
	return layout_attribute

	layout_attribute = cls(self._view, attribute, other, other_attribute)
	self._attributes[name] = layout_attribute
	return layout_attribute

	def _attribute(self, name, definition):
	cls = definition[0]
	attribute = definition[1]
	other_attribute = definition[2]

	assert(isinstance(attribute, LayoutAttribute))
	assert(isinstance(other_attribute, LayoutAttribute))

	if 'superview' in name:
	return self._create_attribute(cls, attribute, other_attribute, self._view.superview)
	elif name.endswith('_to'):
	return partial(self._create_attribute, cls, attribute, other_attribute)
	else:
	assert(other_attribute is LayoutAttribute.notAnAttribute)
	return self._create_attribute(cls, attribute, other_attribute, None)

	def __getattr__(self, name):
	if name in self._definitions:
	return self._attribute(name, self._definitions[name])

	return super().__getattr__(name)


	class LayoutView(ui.View):
	def __init__(self, view):
	assert(isinstance(view, ui.View))

	self._view = view
	self.add_subview(self._view)

	self._view_objc = ObjCInstance(self._view)
	self._objc = ObjCInstance(self)

	self._view_objc.setTranslatesAutoresizingMaskIntoConstraints_(False)
	self._objc.setTranslatesAutoresizingMaskIntoConstraints_(False)

	attributes = [LayoutAttribute.left, LayoutAttribute.right, LayoutAttribute.top, LayoutAttribute.bottom]
	for attribute in attributes:
	constraint = _LayoutConstraint.constraintWithItem_attribute_relatedBy_toItem_attribute_multiplier_constant_(
	self._view_objc, int(attribute), int(LayoutRelation.equal), self._objc, int(attribute), 1.0, 0
	)
	self._objc.addConstraint_(constraint)

	self._layout = None

	@property
	def layout(self):
	if not self._layout:
	self._layout = Layout(self)

	return self._layout

	@property
	def view(self):
	return self._view


	def table_like():
	view = ui.View(background_color='white')

	name_label = LayoutView(ui.Label(
	text='Name', font=('<system-bold>', 18), background_color=(0, 0, 0, 0.1)
	))
	view.add_subview(name_label)

	# 15 points from superview left edge
	name_label.layout.align_left_with_superview.equal = 15
	# 15 points from superview top edge
	name_label.layout.align_top_with_superview.equal = 15

	age_label = LayoutView(ui.Label(
	text='Age', font=('<system-bold>', 18),
	alignment=ui.ALIGN_RIGHT, background_color=(0, 0, 0, 0.1)
	))
	view.add_subview(age_label)

	# Align label baseline with name label
	age_label.layout.align_baseline_to(name_label).equal = 0
	# Right side of age label is 15 points from superview right edge
	age_label.layout.align_right_with_superview.equal = -15
	# Age label width is always 150 pixel
	age_label.layout.width.equal = (150, LayoutPriority.required)

	age_label.layout.leading_offset_to(name_label).equal = 8

	last_name_label = name_label
	last_age_label = age_label

	for i in range(1, 5):
	name_label = LayoutView(ui.Label(
	text='Dummy Name {}'.format(i), background_color=(0, 0, 0, 0.01)
	))
	view.add_subview(name_label)

	# Left egde aligned with left egde of last label
	name_label.layout.align_leading_to(last_name_label).equal = 0
	# Top edge aligned with bottom edge of last label + 16 points
	name_label.layout.top_offset_to(last_name_label).equal = 16
	# Width is 100% of last name label width
	name_label.layout.relative_width_to(last_name_label).equal = 1.0

	age_label = LayoutView(ui.Label(
	text=str(i * 5), alignment=ui.ALIGN_RIGHT, background_color=(0, 0, 0, 0.01)
	))
	view.add_subview(age_label)

	# Baseline aligned with name label
	age_label.layout.align_baseline_to(name_label).equal = 0
	# Right edge aligned with last age label
	age_label.layout.align_trailing_to(last_age_label).equal = 0
	# Width is 100% of width of last age label
	age_label.layout.relative_width_to(last_age_label).equal = 1.0

	last_name_label = name_label
	last_age_label = age_label

	return view


	def center_in_superview():
	view = ui.View(background_color='white')

	label = LayoutView(ui.Label(
	text='80% of width, height, centered', alignment=ui.ALIGN_CENTER,
	background_color=(0, 0, 0, 0.1)
	))
	view.add_subview(label)

	# Align horizontal, vertical center with superview
	label.layout.align_center_x_with_superview.equal = 0
	label.layout.align_center_y_with_superview.equal = 0

	# Width and height 80% of superview width and height
	label.layout.relative_width_to(view).equal = 0.8
	label.layout.relative_height_to(view).equal = 0.8

	return view


	def grid_like():
	view = ui.View(background_color='white')

	rows = 3
	cols = 3
	spacing = 10

	cells = defaultdict(list)

	for row in range(0, rows):
	for col in range(0, cols):
	cell = LayoutView(ui.Label(
	text='R: {} C: {}'.format(row, col),
	alignment=ui.ALIGN_CENTER,
	background_color=(0, 0, 0, 0.1)
	))
	view.add_subview(cell)
	cells[row].append(cell)

	if row == 0:
	# Top cells, align to superview top
	cell.layout.align_top_to(view).equal = spacing

	if row == rows - 1:
	# Bottom cells, align to superview bottom
	cell.layout.align_bottom_to(view).equal = -spacing

	if col == 0:
	# Left column cells, align to superview left
	cell.layout.align_left_to(view).equal = spacing

	if col == cols - 1:
	# Right column cells, align to superview right
	cell.layout.align_right_to(view).equal = -spacing

	if row > 0 or col > 0:
	# Not top/left cell, make same width / height as top/left cell
	cell.layout.relative_width_to(cells[0][0]).equal = 1.0
	cell.layout.relative_height_to(cells[0][0]).equal = 1.0

	if col > 0:
	# Not first column, add spacing between cells
	cell.layout.left_offset_to(cells[row][col - 1]).equal = spacing

	if row > 0:
	# Not first row, add spacing between cells
	cell.layout.top_offset_to(cells[row - 1][col]).equal = spacing

	return view


	def breadcrumb():
	view = ui.View(background_color='white')

	spacing = 8
	previous_label = None

	for title in ('Documents', 'blackmamba', 'experimental', '__init__.py'):
	label = LayoutView(ui.Label(
	text=title,
	background_color=(0, 0, 0, 0.1)
	))
	view.add_subview(label)

	if previous_label:
	label.layout.align_baseline_to(previous_label).equal = 0
	label.layout.leading_offset_to(previous_label).equal = spacing
	else:
	label.layout.align_top_to(view).equal = spacing
	label.layout.align_left_to(view).equal = spacing

	previous_label = label

	return view


	def main():
	datasource = ui.ListDataSource([
	{
	'title': 'Table',
	'view': table_like
	},
	{
	'title': 'Center in superview',
	'view': center_in_superview
	},
	{
	'title': 'Grid',
	'view': grid_like
	},
	{
	'title': 'Breadcrumb',
	'view': breadcrumb
	}
	])

	def did_select(ds):
	nv = ds.tableview.navigation_view

	tv_objc = ObjCInstance(ds.tableview)
	index_path = tv_objc.indexPathForSelectedRow()
	if index_path:
	tv_objc.deselectRowAtIndexPath_animated_(index_path, True)

	row = ds.selected_row
	if row < 0:
	return

	item = ds.items[row]

	view = item['view']()
	view.name = item['title']
	nv.push_view(view)

	datasource.action = did_select

	window_size = ui.get_window_size()
	view = ui.View(width=window_size[0] * 0.8, height=window_size[1] * 0.8)

	tv = ui.TableView(frame=view.bounds, flex='WH')
	tv.name = 'Auto Layout Demo'
	tv.data_source = datasource
	tv.delegate = datasource

	nv = ui.NavigationView(tv, frame=view.bounds, flex='WH')
	view.add_subview(nv)
	view.present('sheet')


	if __name__ == '__main__':
	main()