如何在Kivy中设置小部件/布局的最小允许宽度/高度? [英] How do I set minimum allowable width/height for widget/layout in Kivy?

问题描述

我有3个元素的BoxLayout，我需要第一个和最后一个元素占用最小的可用空间.中间元素的比例是固定的(1:1)，因此当我调整窗口大小时，侧面元素会变得太小，内容会从窗口中消失.我需要标签(或按钮，甚至不同元素集)的文本始终位于标签的内部.此大小不应更大，所以我可以说它应该是固定大小，具体取决于其内容.

I have BoxLayout with 3 elements, I need that first and last elements to occupy minimum available space. Middle element has fixed proportion (1:1), so when I resize the window, side elements become too small and content go out of it. I need e.g. label's (or button's, or even set's of different elements) text to be always inside the label. This size shouldn't be more, so I can say it should be fixed size depending on its content.

更新: 我犯了一个错误，尺寸可以更大，但不能更小.那应该怎么样?

UPDATE: I've made a mistake, size can be more, but not less. How it should be then?

更新: 这就是我的BoxLayout: 当我扩大窗口时，只有侧面部分应该扩大: 当我收缩窗户时，侧面部件应具有一些最小尺寸: 因此，我认为这是固定的最小值.

UPDATE: So it's my BoxLayout: When I expand the window, only side parts should expand: And when I constrict the window, side parts should have some minimum size: So it's kind of fixed minimum I think.

推荐答案

Label的内容大小可通过texture_size属性获得，因此可以将size_hint设置为无"并将大小绑定到内容大小:

Content size of Label is avaiable through texture_size property, so you can set size_hint to None and bind size to content size:

from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.button import Button 

from kivy.lang import Builder

kv = '''
<MyButton>:
    size_hint: None, 1
    size: self.texture_size
'''
Builder.load_string(kv)

class MyButton(Button):
    pass

class MyWidget(BoxLayout):
    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        self.add_widget(MyButton(text="Fixed size button"))
        self.add_widget(Button(text="Normal button"))
        self.add_widget(MyButton(text="Fixed size button"))         

class MyApp(App):
    def build(self):
        return MyWidget()

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

您还应该检查text_size属性.来自文档:通过默认情况下，标签不限制于任何边界框.您可以使用此属性设置标签的大小限制.文本将自动流入限制中.因此，尽管不会减小字体大小，但文本仍会排列为适合尽可能地放进盒子里，盒子外面的任何文字都会被剪掉."例如:

You should also check text_size property. From documentation: "By default, the label is not constrained to any bounding box. You can set the size constraint of the label with this property. The text will autoflow into the constrains. So although the font size will not be reduced, the text will be arranged to fit into the box as best as possible, with any text still outside the box clipped". For example:

from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.button import Button 

from kivy.lang import Builder

kv = '''
<MyButton>:
    text_size: self.size
    valign: "middle"
    halign: "center"
'''
Builder.load_string(kv)

class MyButton(Button):
    pass

class MyWidget(BoxLayout):
    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        self.add_widget(MyButton(text="Example text which is too long to fit in one line"))
        self.add_widget(Button(text="Normal button"))
        self.add_widget(MyButton(text="Example text which is too long to fit in one line"))

class MyApp(App):
    def build(self):
        return MyWidget()

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

更新 如果您想进一步控制小部件的缩放方式，则可以创建一种方法来计算小部件的值，并将其绑定到不断变化的size属性(bind或实现on_size()).例如:

UPDATE If you want even more control about the way widgets scale, you can create method which calculate values for widgets and have it binded to changing size property (either bind or implementing on_size()). For example:

from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.widget import Widget
from kivy.uix.label import Label

from kivy.lang import Builder

from functools import partial

kv = '''
<CentralWidget>:
    pos_hint: {'center_y': .5} 
    size_hint: None, None
    canvas:
        Color:
            rgb: 1, 0, 1
        Rectangle:
            pos: self.pos
            size: self.size

<SideWidget>:
    pos_hint: {'center_y': .5} 
    size_hint: None, 1
    canvas.before:
        Color:
            rgb: 0, 0, 1
        Rectangle:
            pos: self.pos
            size: self.size
'''

Builder.load_string(kv)

class CentralWidget(Widget):
    pass

class SideWidget(Label):
    pass

class MyWidget(BoxLayout):
    def __init__(self, **kwargs):
        super().__init__(**kwargs)

        w1 = SideWidget(text="............................")
        w2 = CentralWidget()
        w3 = SideWidget(text="............................")

        self.add_widget(w1)
        self.add_widget(w2)
        self.add_widget(w3)

    def on_size(self, *args):
        # self.size - size of parent widget
        # self.children - children of widget
        # self.children[0].texture_size - sife of content of selectend children widget
        # self.children[0].size - size of selected children widget to set
        if((self.size[0]-500)/2 > self.children[0].texture_size[0]):
            self.children[0].size = ((self.size[0]-500)/2, 0)     
            self.children[1].size = (500, 500)   
            self.children[2].size = ((self.size[0]-500)/2, 0)   
        else:
            self.children[1].size = (self.size[0]-2*self.children[0].texture_size[0], self.size[0]-2*self.children[0].texture_size[0])  

class MyApp(App):
    def build(self):
        return MyWidget()

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

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