python - 触摸屏滚动 Tkinter Python

Question

我正在为带有 7 英寸触摸屏的 python 树莓派制作一个信息亭应用程序。 一切正常，现在，我正在尝试使滚动条像在触摸屏上一样工作。我知道 raspbian 没有合适的触摸界面，所以，屏幕上的每一次触摸都相当于鼠标点击，如果我移动手指触摸屏幕，就像拖动功能一样。

为了在 python 上实现这个，我使用了我修改过的版本代码 Vertical Scrolled Frame使用 Canvas ，我需要添加事件绑定(bind) <ButtonPress-1>和 <B1-Motion> .

<ButtonPress-1>可能会保存点击的 y 位置并启用 bind_all <B1-Motion> 的功能.

<B1-Motion>可能会将滚动设置向上或向下设置 <ButtonPress-1> 保存的 y 值之间的差异和 event.y本次事件。

<ButtonRelease-1>可能会禁用 bind_all函数 <unbind_all>卷轴的。

我添加的事件代码是这样的，但我不知道如何让它正常工作 .yview Canvas 的功能，使我的功能按预期工作。

def moving(event):
    #In this part I don't know how to make my effect
    self.canvas.yview('scroll',event.y,"units")

def clicked(event):
    global initialy
    initialy = event.y
    self.canvas.bind_all('<B1-Motion>', moving)

def released(event):
    self.canvas.unbind_all('<B1-Motion>')

self.canvas.bind_all('<ButtonPress-1>',clicked)
self.canvas.bind_all('<ButtonRelease-1>', released)

Answer 1

服用 Saad的代码作为基础，我对其进行了修改以使其适用于每个 S.O. (win, linux,mac) 使用 yview_moveto 并且我应用了一些修改，正如我在此处解释的那样。

编辑:我已经编辑了代码以显示完整的类(class)。

class VerticalScrolledFrame(Frame):
    """A pure Tkinter scrollable frame that actually works!
    * Use the 'interior' attribute to place widgets inside the scrollable frame
    * Construct and pack/place/grid normally
    * This frame only allows vertical scrolling

    """
    def __init__(self, parent, bg,*args, **kw):
        Frame.__init__(self, parent, *args, **kw)

        # create a canvas object and a vertical scrollbar for scrolling it

        canvas = Canvas(self, bd=0, highlightthickness=0,bg=bg)
        canvas.pack(side=LEFT, fill=BOTH, expand=TRUE)

        # reset the view
        canvas.xview_moveto(0)
        canvas.yview_moveto(0)

        self.canvasheight = 2000

        # create a frame inside the canvas which will be scrolled with it
        self.interior = interior = Frame(canvas,height=self.canvasheight,bg=bg)
        interior_id = canvas.create_window(0, 0, window=interior,anchor=NW)

        # track changes to the canvas and frame width and sync them,
        # also updating the scrollbar
        def _configure_interior(event):
            # update the scrollbars to match the size of the inner frame
            size = (interior.winfo_reqwidth(), interior.winfo_reqheight())
            canvas.config(scrollregion="0 0 %s %s" % size)
            if interior.winfo_reqwidth() != canvas.winfo_width():
                # update the canvas's width to fit the inner frame
                canvas.config(width=interior.winfo_reqwidth())
        interior.bind('<Configure>', _configure_interior)

        def _configure_canvas(event):
            if interior.winfo_reqwidth() != canvas.winfo_width():
                # update the inner frame's width to fill the canvas
                canvas.itemconfigure(interior_id, width=canvas.winfo_width())
        canvas.bind('<Configure>', _configure_canvas)

        self.offset_y = 0
        self.prevy = 0
        self.scrollposition = 1

        def on_press(event):
            self.offset_y = event.y_root
            if self.scrollposition < 1:
                self.scrollposition = 1
            elif self.scrollposition > self.canvasheight:
                self.scrollposition = self.canvasheight
            canvas.yview_moveto(self.scrollposition / self.canvasheight)

        def on_touch_scroll(event):
            nowy = event.y_root

            sectionmoved = 15
            if nowy > self.prevy:
                event.delta = -sectionmoved
            elif nowy < self.prevy:
                event.delta = sectionmoved
            else:
                event.delta = 0
            self.prevy= nowy

            self.scrollposition += event.delta
            canvas.yview_moveto(self.scrollposition/ self.canvasheight)

        self.bind("<Enter>", lambda _: self.bind_all('<Button-1>', on_press), '+')
        self.bind("<Leave>", lambda _: self.unbind_all('<Button-1>'), '+')
        self.bind("<Enter>", lambda _: self.bind_all('<B1-Motion>', on_touch_scroll), '+')
        self.bind("<Leave>", lambda _: self.unbind_all('<B1-Motion>'), '+')