在Kivy中使用和移动小部件/按钮 [英] Using and moving Widgets/Buttons in Kivy
问题描述
我只是从Kivy开始，这与我习惯的不同，如果我犯了愚蠢的错误，我深表歉意！
I'm just starting off with Kivy and it's different to what I'm used to, apologies if I'm making stupid mistakes!
现在，我正在尝试创建一个执行以下操作的应用程序:
Right now I'm trying to create an app that does the following:
- 允许创建节点(现在为椭圆).
- 允许用户通过拖动来定位节点.
- 允许用户用线连接节点.
到目前为止，我已经取得了第一个，而第二个则有所成就.
So far I've achieved the first, and the second somewhat.
目前，我的拖动效果不太好.如果我太快地移动了鼠标，它将取消move方法(因为它不再处于接触状态).有没有更好的方法来产生拖动效果，或者我只是提高刷新率(如果可以，怎么办?).
Right now my dragging is not working too well. If I move the mouse too quickly it cancels the move method (as it is no longer in contact). Is there a better way to produce dragging or do I just increase the refresh rate (if so how?).
def on_touch_move(self, touch):
if self.collide_point(touch.x, touch.y):
self.pos=[touch.x-25, touch.y-25]
我尝试使用按钮来代替，使用on_press方法来更好地跟踪运动.但是现在我很难更新按钮的位置(主要是语法).
I've tried using Buttons instead, using the on_press method to track the moving better. However now I'm having difficulty updating the position of the button (mostly just syntax).
class GraphNode(Button):
background_disabled_down=1
background_disabled_normal=1
def moveNode(self):
with touch:
self.pos=[touch.x-25, touch.y-25]
我不知道如何使用接触值，并不断出现一系列错误. (显然当前的尝试没有用，我只是觉得很有趣).
I have no idea how to use the touch value, and keep getting an array of errors. (Obviously the current attempt doesn't work, I just thought it was funny).
您可能会说，我还不知道如何摆脱按钮图形，因为我想使用椭圆形.另外，如果有人可以告诉我如何在按钮按下时改变椭圆的颜色，那会很酷！
As you could probably tell, I also don't know how to get rid of the button graphics, as I want to use the ellipse. As an added bonus if someone could show me how to change the colour of the ellipse on button press that would be cool!
kv文件:
<GraphNode>:
size: 50, 50
canvas:
Ellipse:
pos: self.pos
size: self.size
on_press:
root.moveNode()
我希望能够使用触摸信息来更新位置，但是不知道如何在此处实现.
I want to be able to use the touch information to update the position, but don't know how to implement it here.
全核心python代码:
Full core python code:
from kivy.app import App
from kivy.uix.widget import Widget
from kivy.uix.button import Button
from kivy.properties import NumericProperty, ReferenceListProperty,\
ObjectProperty
from kivy.graphics import Color, Ellipse, Line
class GraphInterface(Widget):
node = ObjectProperty(None)
class GraphApp(App):
def build(self):
node = GraphNode()
game = GraphInterface()
createNodeButton = Button(text = 'CreateNode', pos=(100,0))
createEdgeButton = Button(text = 'CreateEdge')
game.add_widget(createNodeButton)
game.add_widget(createEdgeButton)
def createNode(instance):
game.add_widget(GraphNode())
print "Node Created"
def createEdge(instance):
game.add_widget(GraphEdge())
print "Edge Created"
createNodeButton.bind(on_press=createNode)
createEdgeButton.bind(on_press=createEdge)
return game
class GraphNode(Button):
def moveNode(self):
with touch:
self.pos=[touch.x-25, touch.y-25]
#def onTouchMove(self, touch):
# if self.collide_point(touch.x, touch.y):
# self.pos=[touch.x-25, touch.y-25]
pass
class GraphEdge(Widget):
def __init__(self, **kwargs):
super(GraphEdge, self).__init__(**kwargs)
with self.canvas:
Line(points=[100, 100, 200, 100, 100, 200], width=1)
pass
if __name__ == '__main__':
GraphApp().run()
如果您需要任何其他信息，或者有任何不清楚的地方，请告诉我！
If you need any other info, or anything is unclear, please let me know!
第二个问题移至:在Kivy中创建动态绘制的线.
推荐答案
首先，您应该阅读触摸事件在Kivy中.这里特别有趣的是有关捕获触摸事件的部分.基本上，您可以抓住"触摸以确保抓取小部件将始终从该触摸接收到更多事件，换句话说，该触摸事件之后的on_touch_move和on_touch_up将被发送到您的小部件.
First, you should read up on touch events in Kivy. Of particular interest here is the section on grabbing touch events. Basically, you can "grab" a touch to ensure that the grabbing widget will always receive further events from that touch - in other words, the on_touch_move and on_touch_up following that touch event will be sent to your widget.
基本示例:
class MyWidget(Widget):
def on_touch_down(self, touch):
if self.collide_point(*touch.pos):
touch.grab(self)
# do whatever else here
def on_touch_move(self, touch):
if touch.grab_current is self:
# now we only handle moves which we have grabbed
def on_touch_up(self, touch):
if touch.grab_current is self:
touch.ungrab(self)
# and finish up here
但是，甚至更好！如果您希望能够拖动窗口小部件，则Kivy已经具有以下功能: Scatter .
But, even better! If you want to be able to drag widgets around, Kivy already has that: Scatter.
只需将窗口小部件包装在Scatter中，即可将其拖动.您还可以使用多点触控来旋转和缩放Scatter，但是您可以轻松地禁用该(kv):
Just wrap your widget in a Scatter and you can drag it around. You can also use multitouch to rotate and scale a Scatter, but you can easily disable that (kv):
FloatLayout:
Scatter:
do_scale: False
do_rotation: False
MyWidget:
旁注-这是不正确的:
Side note - this is incorrect:
class GraphNode(Button):
background_disabled_down=1
background_disabled_normal=1
background_disabled_down和background_disabled_normal是 Kivy属性-您应设置__init__中的那些值.
background_disabled_down and background_disabled_normal are Kivy properties - you should set those values in __init__.
强制这些值:
class GraphNode(Button):
def __init__(self, **kwargs):
super(GraphNode, self).__init__(background_disabled_down='',
background_disabled_normal='', **kwargs)
建议这些值(更好的选择):
Suggest these values (better option):
class GraphNode(Button):
def __init__(self, **kwargs):
kwargs.setdefault('background_disabled_down', '')
kwargs.setdefault('background_disabled_normal', '')
super(GraphNode, self).__init__(**kwargs)
最后，请注意，这些属性是指向用于禁用的Button 的图像的文件名.如果删除这些值并禁用按钮，则不会绘制任何背景.
Finally, note that these properties are filenames pointing to the images used for the disabled Button. If you remove these values, and disable your button, it will draw no background whatsoever.
这篇关于在Kivy中使用和移动小部件/按钮的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
