如何调整可变高度文本属性 kivy？

Question

我有一个很长的 kivy 文本。我想调整动态高度取决于文本的数量。

我的代码是这样的。

import kivy
from kivy.app import App 
from kivy.uix.label import Label
from kivy.uix.gridlayout import GridLayout


class DynamicHeight(App):y
    def build(self):
        grid = gl = GridLayout(cols=1)

        for i in range(3):
            l = Label(text='Text a longer line line line line line line line line', halign='left',text_size=(300, None))
            grid.add_widget(l)

        return grid

DynamicHeight().run()

我要根据文字的多少调整那个label的高度或者gridlayout的行高。

Answer 1

虽然已经提出了一些解决方案，但我觉得他们没有利用 kivy 的做事方式，而且这种方式更干净。您需要将 text_size 绑定到可用宽度，并将小部件的高度绑定到渲染的纹理大小。

from kivy.app import App
from kivy.uix.label import Label
from kivy.uix.gridlayout import GridLayout
from kivy.uix.floatlayout import FloatLayout


class MyApp(App):
    def build(self):
        root = FloatLayout()

        b = GridLayout(
            cols=1,
            pos_hint={
                'center_x': .5,
                'center_y': .5},
            size_hint=(None, None),
            spacing=20,
            width=200)
        b.bind(minimum_height=b.setter('height'))
        root.add_widget(b)

        for text_length in range(0, 80, 20):
            l = Label(
                text='word ' * text_length,
                size_hint_y=None)
            l.bind(width=lambda s, w:
                   s.setter('text_size')(s, (w, None)))
            l.bind(texture_size=l.setter('size'))
            b.add_widget(l)

        return root


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

Answer 2

在 thopiekar 的帮助下，我找到了解决方案。

对于那些需要它的人。到目前为止，我还没有发现没有这种方法的kivy可以做

import kivy
from kivy.app import App 
from kivy.uix.label import Label
from kivy.uix.gridlayout import GridLayout
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.button import Button


class MultiLineLabel(Button):
    def __init__(self, **kwargs):
        super(MultiLineLabel, self).__init__( **kwargs)
        self.text_size = self.size
        self.bind(size= self.on_size)
        self.bind(text= self.on_text_changed)
        self.size_hint_y = None # Not needed here

    def on_size(self, widget, size):
        self.text_size = size[0], None
        self.texture_update()
        if self.size_hint_y == None and self.size_hint_x != None:
            self.height = max(self.texture_size[1], self.line_height)
        elif self.size_hint_x == None and self.size_hint_y != None:
            self.width  = self.texture_size[0]

    def on_text_changed(self, widget, text):
        self.on_size(self, self.size)


class DynamicHeight(App):
    def build(self):
        grid = GridLayout(cols=1,size_hint_x=None, width="300dp")

        l=['This Text very long, should add multiple lines, automatically. This Text very long, should add multiple lines, automatically', 'One line']

        for i in l:
            l = MultiLineLabel(text=i)
            grid.add_widget(l)
        return grid

DynamicHeight().run()

而且效果很好！！！！！！

Answer 3

text.size() 方法不会改变标签的height 属性。如果文字过长，会与下面的内容重叠：

from kivy.app import App 
from kivy.uix.label import Label
from kivy.uix.button import Button
from kivy.uix.gridlayout import GridLayout


class DynamicHeight(App):
    def build(self):
        layout = GridLayout(cols=1, spacing=20)

        l = Label(text='! '*100, text_size=(10, None),  size_hint_y=None, height=10)
        b = Button(text='...', size_hint_y=None)
        layout.add_widget(l)
        layout.add_widget(b)

        return layout

DynamicHeight().run()

您需要计算文本的高度并手动设置height 属性。我不知道有什么好的和干净的方法来做到这一点。这是一个肮脏的方式：

before = label._label.render()
label.text_size=(300, None)
after = label._label.render()
label.height = (after[1]/before[1])*before[1] # ammount of rows * single row height

例子：

from kivy.app import App 
from kivy.uix.label import Label
from kivy.uix.gridlayout import GridLayout
from kivy.uix.scrollview import ScrollView

class DynamicHeight(App):
    def build(self):
        layout = GridLayout(cols=1, size_hint_y=None, spacing=20)
        layout.bind(minimum_height=layout.setter('height'))
        for i in xrange(1, 20):
            l = Label(text='Text ' * (i*10), text_size=(300, None), size_hint_y=None)

            # calculating height here 
            before = l._label.render()
            l.text_size=(300, None)
            after = l._label.render()
            l.height = (after[1]/before[1])*before[1] # ammount of rows * single row height
            # end

            layout.add_widget(l)
        root = ScrollView()
        root.add_widget(layout)
        return root

DynamicHeight().run()

Answer 4

根据 tshirtman 的回答，我创建了在 kv-lang 中执行相同操作的代码。发生了什么可能会更清楚一些，因为您不需要分析回调函数。

发生的情况是标签的宽度根据布局设置，而高度设置为文本的纹理大小。所以随着文本字符串变长，纹理只能增加高度，我们可以在上面应用，通过将 boxlayout 的高度设置为 my_label.height。

# -*- coding:utf8 -*-

from kivy.lang import Builder
from kivy.app import App
from kivy.uix.label import Label
from kivy.uix.boxlayout import BoxLayout
from kivy.properties import StringProperty
from kivy.core.window import Window
Window.size = (400, 700)

PLACEHOLDER_TEXT = u'''The bindings illustrated in tshirtman's example are created automatically when using kv-lang.
Notice how the "id: my_label" allows us to access the Label's attributes in the BoxLayout's height declaration.'''

kv_string = """
<Example>:
    orientation: 'vertical'
    BoxLayout:
        # colored background for affected area:
        canvas.before:
            Color:
                rgba: 0.3, .4, .4, .6
            Rectangle:
                pos: self.pos
                size: self.size
        size_hint_y: None
        height: my_label.height
        Label:
            id: my_label
            text: root.text
            font_size: '14dp'
            text_size: (self.width, None)
            size: self.texture_size
            valign: 'top'
            halign: 'left'
    BoxLayout:
        orientation: 'vertical'
        size_hint_y: 1
        canvas.before:
            Color:
                rgba: 0.9, .0, .5, .6
            Rectangle:
                pos: self.pos
                size: self.size
        TextInput:
            text: root.PLACEHOLDER_TEXT
            on_text: root.text = self.text
            text_size: self.size
            auto_indent: True
        Label:
            size_hint_y: None
            height: '50dp'
            text: 'String length: ' + str(len(root.text))
"""

Builder.load_string( kv_string )

class Example (BoxLayout ):
    PLACEHOLDER_TEXT = PLACEHOLDER_TEXT
    text = StringProperty(  )
    def __init__(self, **kwargs):
        super( Example, self).__init__(**kwargs)

class MyApp(App):
    def build(self):
        root = Example()
        return root

MyApp().run()