您可以将canvas的角度绑定到
NumericProperty，以从代码内部对其进行更改。您需要做的就是正确计算这些角度。在玩了一点之后，我创建了以下代码：
from kivy.app import Appfrom kivy.uix.widget import Widgetfrom kivy.lang import Builderfrom kivy.animation import Animationfrom kivy.properties import NumericPropertyimport mathkv = '''<Dial>: canvas: Rotate: angle: root.angle origin: self.center Color: rgb: 1, 0, 0 Ellipse: size: min(self.size), min(self.size) pos: 0.5*self.size[0] - 0.5*min(self.size), 0.5*self.size[1] - 0.5*min(self.size) Color: rgb: 0, 0, 0 Ellipse: size: 50, 50 pos: 0.5*root.size[0]-25, 0.9*root.size[1]-25'''Builder.load_string(kv)class Dial(Widget): angle = NumericProperty(0) def on_touch_down(self, touch): y = (touch.y - self.center[1]) x = (touch.x - self.center[0]) calc = math.degrees(math.atan2(y, x)) self.prev_angle = calc if calc > 0 else 360+calc self.tmp = self.angle def on_touch_move(self, touch): y = (touch.y - self.center[1]) x = (touch.x - self.center[0]) calc = math.degrees(math.atan2(y, x)) new_angle = calc if calc > 0 else 360+calc self.angle = self.tmp + (new_angle-self.prev_angle)%360 def on_touch_up(self, touch): Animation(angle=0).start(self)class DialApp(App): def build(self): return Dial()if __name__ == "__main__": DialApp().run()
我正在计算初始（按鼠标后）和以后的角度之间的差异
on_touch_move。由于angle是一个属性，因此我也可以使用它来修改它，
kivy.animation以在释放鼠标按钮后使拨盘回旋。
编辑
on_touch_down子圈子活动：
from kivy.app import Appfrom kivy.uix.widget import Widgetfrom kivy.uix.floatlayout import FloatLayoutfrom kivy.lang import Builderfrom kivy.animation import Animationfrom kivy.properties import NumericPropertyimport mathkv = '''<Dial>: circle_id: circle_id size: root.size pos: 0, 0 canvas: Rotate: angle: self.angle origin: self.center Color: rgb: 1, 0, 0 Ellipse: size: min(self.size), min(self.size) pos: 0.5*self.size[0] - 0.5*min(self.size), 0.5*self.size[1] - 0.5*min(self.size) Circle: id: circle_idsize_hint: 0, 0 size: 50, 50 pos: 0.5*root.size[0]-25, 0.9*root.size[1]-25 canvas: Color: rgb: 0, 1, 0 Ellipse: size: 50, 50 pos: self.pos '''Builder.load_string(kv)class Circle(Widget): def on_touch_down(self, touch): if self.collide_point(*touch.pos): print "small circle clicked"class Dial(Widget): angle = NumericProperty(0) def on_touch_down(self, touch): if not self.circle_id.collide_point(*touch.pos): print "big circle clicked" y = (touch.y - self.center[1]) x = (touch.x - self.center[0]) calc = math.degrees(math.atan2(y, x)) self.prev_angle = calc if calc > 0 else 360+calc self.tmp = self.angle return super(Dial, self).on_touch_down(touch) # dispatch touch event futher def on_touch_move(self, touch): y = (touch.y - self.center[1]) x = (touch.x - self.center[0]) calc = math.degrees(math.atan2(y, x)) new_angle = calc if calc > 0 else 360+calc self.angle = self.tmp + (new_angle-self.prev_angle)%360 def on_touch_up(self, touch): Animation(angle=0).start(self)class DialApp(App): def build(self): return Dial()if __name__ == "__main__": DialApp().run()
