Kivy 更新标签纹理

Question

我需要更新一组标签，一次1个，但我还需要在功能完成之前查看更改的效果。期望的结果是一种加载条。

就目前而言，我的代码在函数结束时一次性应用所有更改。

（简化代码以方便阅读）

main.py

def TextAnimation(self):
    #self.ids.??? are labels
    self.ids.x1y1.text = "-"
    self.ids.x2y1.text = "-"
    self.ids.x3y1.text = "-"
    self.ids.x1y1.texture_update()
    self.ids.x2y1.texture_update()
    self.ids.x3y1.texture_update()
    time.sleep(0.2)
    self.ids.x4y1.text = "-"
    self.ids.x5y1.text = "-"
    self.ids.x6y1.text = "-"
    self.ids.x4y1.texture_update()
    self.ids.x5y1.texture_update()
    self.ids.x6y1.texture_update()
    time.sleep(0.2) 

我的印象是labelName.texture_update() 立即调用下一帧，而不是等待函数结束，但似乎不像文档中描述的那样工作；

Warning The texture update is scheduled for the next frame. If you need the texture immediately after changing a property, you have to call the texture_update() method before accessing texture:

    l = Label(text='Hello world')
    # l.texture is good
    l.font_size = '50sp'
    # l.texture is not updated yet
    l.texture_update()
    # l.texture is good now.

Answer 1

您应该使用Clock 来安排标签文本更改。考虑这段代码：

test.kv:

#:kivy 1.9.0
Root:
    cols: 1

    Label:
        id: my_label

    Button:
        text: 'animate text'
        on_press: root.animate_text()

main.py:

#!/usr/bin/env python
# -*- coding: utf-8 -*-
from kivy.app import App
from kivy.uix.gridlayout import GridLayout
from kivy.clock import Clock


class Root(GridLayout):

    string = ''

    def animate_text(self):
        Clock.schedule_interval(self.update_label, 0.1)

    def update_label(self, dt):
        self.string += '>'
        self.ids.my_label.text = self.string

        if len(self.string) > 20:
            Clock.unschedule(self.update_label)
            self.string = ''
            self.ids.my_label.text = 'DONE'


class Test(App):
    pass


Test().run()