ScatterLayout - do_translation不工作

Question

我的代码

import kivy
from kivy.uix.scatterlayout import ScatterLayout
from kivy.app import App
from kivy.uix.image import Image
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.button import Button

class MyScatter(ScatterLayout):

    def __init__(self, *args, **kwargs):
        super(MyScatter, self).__init__(*args, **kwargs)
        self.img = Image(source='img.png', keep_ratio=True, center = self.center)
        self.add_widget(self.img)

class MainApp(App):
    def build(self):
        mainbox = FloatLayout()
        mainbox.add_widget(Button(text="Prev",
                                  font_size="17dp",
                                  size_hint=(.15, .15),
                                  pos_hint={"left":1,
                                            "center_y":0.5},
                                  ))
        ms = MyScatter(scale=1, pos_hint={"center_x":0.33, "center_y":0.5}, do_scale = True, do_rotation = False, do_translation = True)
        mainbox.add_widget(ms)
        return mainbox

root = MainApp()
root.run()

按钮和图像的位置是根据我的需要。但是，我为do_translation定义了MyScatter = True，但它不起作用。

Answer 1

我启发了here并编写了以下代码：

import kivy
from kivy.uix.scatterlayout import ScatterLayout
from kivy.app import App
from kivy.uix.image import Image
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.button import Button

class MyScatter(ScatterLayout):

    def __init__(self, *args, **kwargs):
        super(MyScatter, self).__init__(*args, **kwargs)
        self.img = Image(source='img.png', keep_ratio=True, pos_hint={"center_x":0.33, "center_y":0.5})
        self.add_widget(self.img)

    def on_touch_move(self, touch): #magic time!!!!
       res =  super(MyScatter, self).on_touch_move(touch)
       if res: #Yay do something!
           self.img.pos = (self.center_x, self.center_y)
       return res

class MainApp(App):
    def build(self):
        mainbox = FloatLayout()
        mainbox.add_widget(Button(text="Prev",
                                  font_size="17dp",
                                  size_hint=(.15, .15),
                                  pos_hint={"left":1,
                                            "center_y":0.5},
                                  ))
        ms = MyScatter(scale=1, do_scale = True, do_rotation = False, do_translation = True)
        mainbox.add_widget(ms)
        return mainbox

root = MainApp()

root.run()

好像很管用。请告诉我这是个好办法。