Kivy:如何将画布用于在 python 中创建的小部件

2022-01-15 00:00:00 python kivy canvas

问题描述

我想在我的复选框中添加一个画布来更改它们的颜色.我找到了这个答案，但我正在努力实现它.我的复选框是使用以下代码在 python 中创建的:

I would like to add a canvas to my checkboxes to change their color. I have found this answer, but I am struggling to implement it. My checkboxes are created in python with this code:

checkb= CheckBox()
layout.add_widget(checkb)

尝试 1:我尝试了 这里但没有成功:

Attempt 1: I tried the solution from here but without success: 

checkb= CheckBox()
checkb.canvas.add(Color(1., 1., 0))
checkb.canvas.add(Rectangle(size=(50, 50)))
layout.add_widget(checkb)

尝试 2:我还尝试在构建器中创建一个自定义复选框，但没有找到使其工作的方法(我找不到有关这种设置的任何信息，所以我不确定甚至可以让它工作):

Attempt 2: I also tried to come up with a custom checkbox created in the builder but didn't find a way to make it work (I couldn't find any info about this kind of setup, so I am not sure it's even possible to make it work): 

Builder.load_string('''
<CustomCk@CheckBox>:
    canvas.before:
        Color:
            rgb: 1,0,0
        Rectangle:
            pos:self.center_x-8, self.center_y-8
            size:[16,16]
        Color:
            rgb: 0,0,0
        Rectangle:
            pos:self.center_x-7, self.center_y-7
            size:[14,14]                

''')

和

checkb= CustomCk()
layout.add_widget(checkb)

<小时>

我尝试使用 with 语句:

Edit : my try with the with statement:

checkb= CheckBox()  
with checkb.canvas:
    Color(1, 2, 0)
    Rectangle(size=(50, 50))
layout.add_widget(checkb)

解决方案

你应该使用 Python 代码中的 with 语句

You should use the with statement from your python code

with checkb.canvas:
    Color(1., 1., 0)
    Rectangle(size=(50, 50))

您的其他方法似乎更好，只需稍微修复一下:

Your other approach seems better, just fix it a bit:

Builder.load_string('''
<CustomCk>:
    canvas.before:
        Color:
            rgb: 1,0,0
        Rectangle:
            pos:self.center_x-8, self.center_y-8
            size:[16,16]
        Color:
            rgb: 0,0,0
        Rectangle:
            pos:self.center_x-7, self.center_y-7
            size:[14,14]                

    ''')

class CustomCk(CheckBox): #define the class in the python file... 
     pass

checkb= CustomCk()
layout.add_widget(checkb)

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