Question

虽然使用“自定义”小部件，但是在pos_hint参数中仅评估“ x”和“ y”参数。但是，如果我使用center_x，center_y或top之类的其他键，则不会评估键值。在下面给出的示例程序中，如果我将pos_hint用作center_x和center_y，则该行在布局的中间未对齐。但是，如果我使用x和y，则参数对齐有效。

from kivy.app import App
from kivy.graphics import Line
from kivy.uix.scatter import Scatter
from kivy.uix.widget import Widget
from kivy.uix.button import Button
from kivy.uix.relativelayout import RelativeLayout
from kivy.uix.scatterlayout import ScatterLayout


class MyPaintWidget(Scatter):

    def __init__(self, **kwargs) :
        super(MyPaintWidget, self).__init__(**kwargs)

    def create_figure(self,  **kwargs):
        self.canvas.add(Line( points=[0, 10, 30, 10]))
        return self

class MyPaintApp(App):

    def build(self):
        parent = RelativeLayout()

        #self.painter = MyPaintWidget(pos_hint={'center_x': 0.5, 'center_y':0.5}) Not working with center_x and center_y alignment
        self.painter = MyPaintWidget(pos_hint={'x': 0.5, 'y':0.5}) #working with x and y parameter

        parent.add_widget(self.painter.create_figure())

        return parent

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

即使尝试使用注释部分中提到的示例KV文件

from kivy.app import App
from kivy.graphics import Line
from kivy.uix.scatter import Scatter
from kivy.uix.relativelayout import RelativeLayout
from kivy.lang import Builder

KV = '''
<LineRectangle>:
    canvas:
        Color:
            rgba: .1, .1, 1, .9
        Line:
            width: 2.
            rectangle: (self.x, self.y, self.width, self.height)
    Label:
        center: root.center
        text: 'Rectangle'
'''

class LineRectangle(Scatter):
      pass

class MyPaintApp(App):

    def build(self):
        Builder.load_string(KV)
        root = RelativeLayout()
        #root.add_widget(LineRectangle(pos_hint={'center_x':0.5, 'center_y':0.5}, size_hint=(0.2, 0.2)))
        root.add_widget(LineRectangle(pos_hint={'center_x':0.5, 'center_y':0.5}, size_hint=(None, None)))
        return root

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

Answer 1

pos_hint属性允许您以百分比（类似于size_hint）的形式设置小部件在其父布局内的位置。

KIVY自定义小部件pos_hint

1 个答案: