CODEWITHSUNDEEP
pythonkivy
oneace
oneace

Reputation: 117

Get widget XY position after applying pos_hint

After positioning a widget (e.g. Scatter) using pos_hint, how do I get the current x, y position (pos) ?

e.g. 

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.

EDIT: example code 

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()

Upvotes: 2

Views: 2383

Answers (1)

toto_tico
toto_tico

Reputation: 19027

The problem is that the Window (and the layout itself) is not refresh immediately after assigning values that are honoured by layouts (like size_hint or pos_hint). They are updated just after the window is refresh (until the method ends)

You basically can call the method do_layout explicitly. The documentation said that "this method is called when a layout is needed, by a trigger". I have to say that I am not sure if calling it explicitly could cause some problems because this kind of use is not documented. It is working for me but be careful: 

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

This is not necessary when you let the window refresh, i.e. after you can actually see that the Scatter (or any other Widget) has moved.

EDIT: corrected version of the code in the question

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()

Upvotes: 1

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