Question

我有一个有效的Kivy代码，如下所示。我运行后能够绘制随机形状。现在，我想在单击Hello按钮一次后才启用绘图。我该如何修改我的代码？

Python代码

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen, FadeTransition
from kivy.uix.widget import Widget
from kivy.graphics import Line


class Painter(Widget):
    def on_touch_down(self, touch):
        with self.canvas:
            touch.ud["line"] = Line( points = (touch.x, touch.y))
    def on_touch_move(self, touch):
        touch.ud["line"].points += [touch.x, touch.y]

class MainScreen(Screen):
    pass
class ScreenManagement(ScreenManager):
    pass

presentation = Builder.load_file("main3.kv")

class MainApp(App):
    def build(self):
        return presentation

if __name__=="__main__":
    MainApp().run()

kv文件：

#:kivy 1.0.9
ScreenManagement:
    MainScreen:

<MainScreen>:
    name:"main"
    FloatLayout:
        Painter
        Button:
            text: "Hello"
            font_size: 50
            color: 0,1,0,1
            size_hint: 0.3,0.2
            pos_hint: {"right":1, "top":1}

Answer 1

如何制作新的绘画画面。

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen, FadeTransition
from kivy.uix.widget import Widget
from kivy.graphics import Line


KV = '''
ScreenManagement:
    MainScreen:
    PaintScreen:

<MainScreen>:
    name:"main"
    FloatLayout:
        Button:
            text: "Go paint"
            font_size: 50
            color: 0,1,0,1
            size_hint: 0.3,0.2
            pos_hint: {"right":1, "top":1}
            on_release:
                root.manager.current = 'paint'

<PaintScreen@Screen>:
    name: 'paint'
    FloatLayout:
        Button:
            text: "Exit painting"
            font_size: 40
            color: 0,1,0,1
            size_hint: 0.3,0.2
            pos_hint: {"right":1, "top":1}
            on_release:
                root.manager.current = 'main'
        Painter:
'''


class Painter(Widget):
    def on_touch_down(self, touch):
        with self.canvas:
            touch.ud["line"] = Line( points = (touch.x, touch.y))
    def on_touch_move(self, touch):
        touch.ud["line"].points += [touch.x, touch.y]


class MainScreen(Screen):
    pass


class ScreenManagement(ScreenManager):
    pass


class MainApp(App):
    def build(self):
        return Builder.load_string(KV)

if __name__=="__main__":
    MainApp().run()

Answer 2

您可以使用a切换按钮并将其状态链接到Painter：

    ...
    Painter:
        hello_active: hello_button.state == 'down'
    ToggleButton:
        id: hello_button
        text: "Hello"
        font_size: 50
        color: 0,1,0,1
        size_hint: 0.3,0.2
        pos_hint: {"right":1, "top":1}

并在python文件中......

class Painter(Widget):

    hello_active = BooleanProperty(False)

    def on_touch_down(self, touch):
        if not self.hello_active:
            return #nothing to see here ...
        with self.canvas:
            touch.ud["line"] = Line( points = (touch.x, touch.y))
    def on_touch_move(self, touch):
        if 'line' in touch.ud:
            touch.ud["line"].points += [touch.x, touch.y]

KIVY：如何创建一个按钮来启动我的Paint应用程序

2 个答案: