Question

新成员，第一篇文章。我会尽量具体而明确。以下代码摘自kivy关于的网页。我想使用这段代码，但是，我不想使用KV lang和Builder，而是用纯Python 3编写代码。我试图将RecycleBoxLayout类添加为小部件是一个彻底的失败，因为结果只是一个黑色的窗口。只添加＆＃34; viewclass＆＃34;工作中。显然，这里有一些我不理解或遗漏的东西。我还附上了重写代码的尝试。

非常感谢任何帮助。提前谢谢你。

原始代码：

diff -y --suppress-common-lines file1 file2 | wc -l

我的失败尝试：

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.recycleview import RecycleView

Builder.load_string('''
<RV>:
    viewclass: 'Label'
    RecycleBoxLayout:
    default_size: None, dp(56)
    default_size_hint: 1, None
    size_hint_y: None
    height: self.minimum_height
    orientation: 'vertical'
''')

class RV(RecycleView):
    def __init__(self, **kwargs):
        super(RV, self).__init__(**kwargs)
        self.data = [{'text': str(x)} for x in range(100)]

class TestApp(App):
    def build(self):
        return RV()


if __name__ == '__main__':
    TestApp().run()

Answer 1

我一直在寻找同样的东西，我不喜欢kv lang，并且还没有被说服它比在代码中做所有事情更好。

来自https://kivy.org/docs/api-kivy.uix.recycleview.html#kivy.uix.recycleview.RecycleView的样本将按如下方式创建。

from kivy.app import App
from kivy.graphics import Color, Rectangle
from kivy.uix.recycleview import RecycleView
from kivy.uix.recycleview.views import RecycleDataViewBehavior
from kivy.uix.label import Label
from kivy.properties import BooleanProperty
from kivy.uix.recycleboxlayout import RecycleBoxLayout
from kivy.uix.behaviors import FocusBehavior
from kivy.uix.recycleview.layout import LayoutSelectionBehavior

class SelectableRecycleBoxLayout(FocusBehavior, LayoutSelectionBehavior,
                                 RecycleBoxLayout):
    ''' Adds selection and focus behaviour to the view. '''
    def __init__(self, **kw):
        super().__init__(**kw, default_size=(0, 28), default_size_hint=(1, None), size_hint_y=None,
                         touch_multiselect=True, multiselect=True, orientation='vertical')

        self.bind(minimum_height=self._min)

    def _min(self, inst, val):
        self.height = val

class SelectableLabel(RecycleDataViewBehavior, Label):
    ''' Add selection support to the Label '''
    index = None
    selected = BooleanProperty(False)
    selectable = BooleanProperty(True)

    def __init__(self, **kw):
        super().__init__(**kw)
        self.canvas.before.clear()
        with self.canvas.before:
            if self.selected:
                Color(.0, 0.9, .1, .3)
            else:
                Color(0, 0, 0, 1)
            self.rect = Rectangle(size=self.size, pos=self.pos)
        self.bind(size=self._update_rect, pos=self._update_rect)

    def _update_rect(self, inst, value):
        self.rect.pos = inst.pos
        self.rect.size = inst.size

    def refresh_view_attrs(self, rv, index, data):
        ''' Catch and handle the view changes '''
        self.index = index
        return super().refresh_view_attrs(rv, index, data)

    def on_touch_down(self, touch):
        ''' Add selection on touch down '''
        if super(SelectableLabel, self).on_touch_down(touch):
            return True
        if self.collide_point(*touch.pos) and self.selectable:
            return self.parent.select_with_touch(self.index, touch)

    def apply_selection(self, rv, index, is_selected):
        ''' Respond to the selection of items in the view. '''
        self.selected = is_selected
        if is_selected:
            print("selection changed to {0}".format(rv.data[index]))
        else:
            print("selection removed for {0}".format(rv.data[index]))
        self.canvas.before.clear()
        with self.canvas.before:
            if self.selected:
                Color(.0, 0.9, .1, .3)
            else:
                Color(0, 0, 0, 1)
            self.rect = Rectangle(size=self.size, pos=self.pos)


class RV(RecycleView):
    def __init__(self, **kwargs):
        super(RV, self).__init__(**kwargs)
        self.add_widget(SelectableRecycleBoxLayout())
        self.viewclass = 'SelectableLabel'
        self.data = [{'text': str(x)} for x in range(100)]


class TestApp(App):
    def build(self):
        return RV()

if __name__ == '__main__':
    TestApp().run()

KV课程中的顺序非常重要。不确定需要是什么，但是在添加小部件之后需要修改self.data。

Answer 2

我不是Kivy的专家，但我强烈建议您尽可能使用kv lang。它只不过是一个简洁的python，它将使您的代码更清洁。
如果您阅读RecycleBoxLayout高度实验性的文档，您应该使用有效的文档。

话虽这么说，你的代码看起来还不错，但有几个问题。

1）更换 self.viewclass = Label self.viewclass = 'Label'和height
2）您没有在python代码中为size指定orientation，RecycleBoxLayout和{{1}}参数。

Kivy中的RecycleView模块

2 个答案: