Source code for enamlnative.widgets.list_view

"""
Copyright (c) 2017-2018, CodeLV.

Distributed under the terms of the MIT License.

The full license is in the file LICENSE, distributed with this software.

Created on May 20, 2017

 
"""
from atom.api import Bool, ContainerList, Enum, ForwardTyped, Int, Typed, Value
from enaml.core.declarative import d_, observe
from enaml.widgets.toolkit_object import ProxyToolkitObject, ToolkitObject
from .view_group import ProxyViewGroup, ViewGroup


class ProxyListView(ProxyViewGroup):
    """The abstract definition of a proxy ListView object."""

    #: A reference to the widget declaration.
    declaration = ForwardTyped(lambda: ListView)

    def set_items(self, items: list):
        raise NotImplementedError

    def set_span_count(self, count: int):
        raise NotImplementedError

    def set_orientation(self, orientation: str):
        raise NotImplementedError

    def set_arrangement(self, arrangement: str):
        raise NotImplementedError

    def set_selected(self, index: int):
        raise NotImplementedError

    def set_fixed_size(self, fixed_size: bool):
        raise NotImplementedError

    def scroll_to(self, x: int, y: int):
        raise NotImplementedError

    def scroll_to_position(self, position: int):
        raise NotImplementedError


class ProxyListItem(ProxyToolkitObject):
    #: A reference to the widget declaration.
    declaration = ForwardTyped(lambda: ListItem)


[docs]class ListView(ViewGroup):
    """A widget for displaying a large scrollable list of items."""

    #: List of items to display
    items = d_(ContainerList())

    #: use this setting to improve performance if you know that changes
    #: in content do not change the layout size of the RecyclerView
    fixed_size = d_(Bool())

    #: Layout manager to use
    arrangement = d_(Enum("linear", "grid", "staggered"))

    #: Orientation
    orientation = d_(Enum("vertical", "horizontal"))

    #: Span count (only for grid and staggered)
    span_count = d_(Int())

    #: A reference to the ProxyLabel object.
    proxy = Typed(ProxyListView)

    # -------------------------------------------------------------------------
    # Observers
    # -------------------------------------------------------------------------
    @observe("items", "arrangement", "orientation", "span_count", "fixed_size")
    def _update_proxy(self, change):

        super()._update_proxy(change)

[docs]    def scroll_to(self, x: int, y: int):
        """Scroll to the given x,y coordinates within the list"""
        if proxy := self.proxy:
            proxy.scroll_to(x, y)

[docs]    def scroll_to_position(self, position: int):
        """Scroll to the given position in the list"""
        if proxy := self.proxy:
            proxy.scroll_to_position(position)


[docs]class ListItem(ToolkitObject):
    """A holder for a View within a ListItem."""

    #: The item this view should render
    item = d_(Value(), writable=False)

    #: The position of this item within the ListView
    index = d_(Int(), writable=False)

    #: A reference to the ProxyLabel object.
    proxy = Typed(ProxyListItem)