Kivy 布局高度以适应子小部件的高度

Question

我想创建一个布局，其中我有类似于 BoxLayout 的东西，让我能够在我的布局中创建“行”，并且在每个“行”中我想使用另一种 BoxLayout 中的东西来创建“列”。

列不需要均匀分布。例如，我想创建一个 BoxLayout，其中一列带有方形图像，另一列占据剩余的可用宽度。

在我的 gist 上查看代码和屏幕截图：https://gist.github.com/MichaelGradek/e5c50038b947352d9e79

我已经在上面的代码中完成了基本结构，但除此之外，我希望 BoxLayout 的高度适应孩子的高度。

实现这一目标的最佳方法是什么？

谢谢！

Answer 1

不要使用 BoxLayout，使用带有 height: self.minimum_height 的 GridLayout，并为每个子小部件设置手动大小（size_hint_y: None 和 height: some_number）。

Answer 2

对我来说，使用高度为 self.minimum_height 的 GridLayout，然后为每个子小部件设置手动大小（size_hint_y：无和高度：some_number），导致小部件锚定到根窗口的底部。实在想不通为什么？

但是，使用高度为 root.height 的 GridLayout，然后为每个子窗口小部件设置手动大小（size_hint_y：无，高度：some_number）会产生正确的顶部锚定窗口小部件。

Answer 3

以下是我想出的一些技巧，用于根据孩子的高度设置GridLayout 高度，但是，每行都需要一个孩子...所以制作列确实需要添加内部网格布局。

# kv file or string
<Resizing_GridLayout@GridLayout>:
    cols: 1
    row_force_default: True
    foo: [self.rows_minimum.update({i: x.height}) for i, x in enumerate(reversed(list(self.children)))]

可以通过 Python 代码或静态 kv 条目添加以上内容，并且在我的项目中至少可以自行调整包含的子小部件的每一行的大小。

# kv file or string for when above goes funky
<ResizingRow_GridLayout@GridLayout>:
    cols: 1
    height: sum([c.height for c in self.children])

为了完整起见，举个例子说明如何将它们缝合在一起......

# ... assuming above have been set, bellow maybe within another layout
Resizing_GridLayout:
    ResizingRow_GridLayout:
        Label:
            height: 30
            text: 'Label One'
        TextInput:
            height: 30
            multiline: False
            write_tab: False
            hint_text: 'Insert one liner'
    ResizingRow_GridLayout:
        Label:
            height: 45
            text: 'Label two'
        Button:
            text: 'Button One'
            height: 60
        GridLayout:
            rows: 1
            height: 25
            Button:
                text: 'Button Two'
            Button:
                text: 'Button three'

---

更新

modules/adaptive-grid-layout/__init__.py

#!/usr/bin/env python

from collections import OrderedDict
from kivy.uix.gridlayout import GridLayout
from kivy.clock import Clock


class Adaptive_GridLayout(GridLayout):
    """
    Adaptive height and row heights for grid layouts.

    Note this should not be used as a root layout and '_refresh_grids_y_dimension()' method should be used by
    children widgets that change height to update all attached instances of Adaptive_GridLayout (this layout).

    Copyright AGPL-3.0 2019 S0AndS0
    """

    def __init__(self, grow_cols = False, grow_rows = False, **kwargs):
        super(Adaptive_GridLayout, self).__init__(**kwargs)
        self.grow_cols = grow_cols
        self.grow_rows = grow_rows
        self.trigger_refresh_y_dimension = Clock.create_trigger(lambda _: self._refresh_grids_y_dimension(), 0)

    def _yield_tallest_of_each_row(self):
        """ Yields tallest child of each row within gridlayout. """
        current_tallest = None
        for i, c in enumerate(list(reversed(self.children))):
            if current_tallest is None:
                current_tallest = c

            if c.height > current_tallest.height:
                current_tallest = c

            ## Should work around grids without value for 'cols'
            if self.cols is None or self.cols is 0:
                yield current_tallest
                current_tallest = None
            ## Reached last item of current row... Fizzbuzz!
            elif ((i + 1) % self.cols == 0) is True:
                yield current_tallest
                current_tallest = None

    def _calc_child_padding_y(self, child):
        """ Returns total padding for a given child. """
        ## May be faster than asking permission with an if statement as most widgets seem to have padding
        try:
            child_padding = child.padding
        except AttributeError as e:
            child_padding = [0]

        len_child_padding = len(child_padding)
        if len_child_padding is 1:
            padding = child_padding[0] * 2
        elif len_child_padding is 2:
            padding = child_padding[1] * 2
        elif len_child_padding > 2:
            padding = child_padding[1] + child_padding[3]
        else:
            padding = 0

        return padding

    def _calc_min_height(self):
        """ Returns total height required to display tallest children of each row plus spacing between widgets. """
        min_height = 0
        for c in self._yield_tallest_of_each_row():
            min_height += c.height + self._calc_child_padding_y(child = c) + self.spacing[1]
        return min_height

    def _calc_rows_minimum(self):
        """ Returns ordered dictionary of how high each row should be to accommodate tallest children of each row. """
        rows_minimum = OrderedDict()
        for i, c in enumerate(self._yield_tallest_of_each_row()):
            rows_minimum.update({i: c.height + self._calc_child_padding_y(child = c)})
        return rows_minimum

    def _refresh_height(self):
        """ Resets 'self.height' using value returned by '_calc_min_height' method. """
        self.height = self._calc_min_height()

    def _refresh_rows_minimum(self):
        """ Resets 'self.rows_minimum' using value returned by '_calc_rows_minimum' method. """
        self.rows_minimum = self._calc_rows_minimum()

    def _refresh_grids_y_dimension(self):
        """ Updates 'height' and 'rows_minimum' first for spawn, then for self, and finally for any progenitors. """
        spawn = [x for x in self.walk(restrict = True) if hasattr(x, '_refresh_grids_y_dimension') and x is not self]
        for item in spawn:
            item._refresh_rows_minimum()
            item._refresh_height()

        self._refresh_rows_minimum()
        self._refresh_height()

        progenitors = [x for x in self.walk_reverse() if hasattr(x, '_refresh_grids_y_dimension') and x is not self]
        for progenitor in progenitors:
            progenitor._refresh_rows_minimum()
            progenitor._refresh_height()

    def on_children(self, instance, value):
        """ If 'grow_cols' or 'grow_rows' is True this will grow layout that way if needed instead of erroring out. """
        smax = self.get_max_widgets()
        widget_count = len(value)
        if smax and widget_count > smax:
            increase_by = widget_count - smax
            if self.grow_cols is True:
                self.cols += increase_by
            elif self.grow_rows is True:
                self.rows += increase_by
        super(Adaptive_GridLayout, self).on_children(instance, value)

    def on_parent(self, instance, value):
        """ Some adjustments maybe needed to get top row behaving on all platforms. """
        self.trigger_refresh_y_dimension()

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