在應用pos_hint後獲取控件的XY位置

Question

使用pos_hint定位控件（例如Scatter）後，如何獲取當前的x，y位置（pos）？

例如

wid.pos = (250, 350) 
print wid.pos <----- # it print (200, 350). Correct. 
wid.pos_hint = {'top':0.9, 'right':0.5} # moved the widget to other position using pos_hint. 
print wid.pos <----- # it sill print (200, 350) eventhough the widget position has changed. 

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EDIT：例如代碼

from kivy.app import App 
from kivy.lang import Builder 
from kivy.uix.scatter import Scatter 

Builder.load_string(""" 
<Icon@Scatter>: 
    size_hint: .06, .08 

    Image: 
     size: root.size 
     allow_stretch: True 
     keep_ratio: True 
""") 

class Icon(Scatter): 
    def __init__(self, **kwargs): 
     self.pos = (200, 200) 
     self.move() 
     super(Icon, self).__init__(**kwargs) 

    def move(self): 
     print "BEFORE: " 
     print self.pos  # print 200, 200 
     self.pos_hint = {'top':0.9, 'right':0.5} # assume now Scatter has moved to x800 y500. 
     print "AFTER: " 
     print self.pos  # it still print 200, 200 :(


class GameApp(App): 
    def build(self): 
     return Icon() 

if __name__ == '__main__': 
    GameApp().run() 

Answer 1

的問題是，所述窗口（和佈局本身）未分配由佈局兌現值之後立即刷新（如size_hint或pos_hint）。它們在窗口刷新後立即更新（直到方法結束）

您基本上可以明確調用方法do_layout。該文件說，「當需要佈局時，通過觸發器調用此方法」。我不得不說，如果明確地調用它可能會導致一些問題，因爲這種用法沒有記錄。這是爲我工作，但要小心：

wid.pos = (250, 350) 
print wid.pos # it prints (200, 350). Correct. 
wid.pos_hint = {'top':0.9, 'right':0.5} 
print wid.pos # it sill print (200, 350) 
wid.do_layout() 
print wid.pos # it should work now 

當你讓窗口刷新之後，即實際上你可以看到Scatter（或任何其他Widget）移動這是沒有必要的。

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編輯：在問題糾正的代碼版本

from kivy.app import App 
from kivy.lang import Builder 
from kivy.uix.scatter import Scatter 
from kivy.uix.floatlayout import FloatLayout 

Builder.load_string(""" 
<Icon>: 
    size_hint: .06, .08 

    Image: 
     size: root.size 
     allow_stretch: True 
     keep_ratio: True 

<BaseLayout>: 
    icon: _icon 
    Icon: 
     id: _icon 
    Button: 
     text: "Press me" 
     size_hint: .1,.05 
     on_press: _icon.move() 
""") 

class Icon(Scatter): 
    def __init__(self, **kwargs): 
     self.pos = (200, 200) 
     super(Icon, self).__init__(**kwargs) 

    def move(self): 
     print "BEFORE: " 
     print self.pos  # print 200, 200 
     self.pos_hint = {'top':0.9, 'right':0.5} # assume now Scatter has moved to x800 y500. 
     self.parent.do_layout() 
     print "AFTER: " 
     print self.pos  # it still print 200, 200 :(


class BaseLayout(FloatLayout): 
    pass 


class GameApp(App): 
    def build(self): 
     return BaseLayout() 

if __name__ == '__m 
ain__': 
    GameApp().run()