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I have a textinput that I want to focus on when the user clicks/touches on it. (Fairly standard!) It inherits from DragableObject (a user example in the kivy wiki) and GridLayout.

class DragableObject( Widget ):
    def on_touch_down( self, touch ):
        if self.collide_point( *touch.pos ):
            touch.grab( self )
            return True

    def on_touch_up( self, touch ):
        if touch.grab_current is self:
            touch.ungrab( self )
            return True

    def on_touch_move( self, touch ):
        if touch.grab_current is self:
            self.pos = touch.x-self.width/2, touch.y-self.height/2

class MyWidget(DragableObject, GridLayout):
    def __init__(self, **kwargs):
        kwargs['orientation'] = 'lr-tb'
        kwargs['spacing'] = 10
        kwargs['size_hint'] = (None, None)
        kwargs['size'] = (200, 80)

        self.cols = 2
        super(MyWidget, self).__init__(**kwargs)

        with self.canvas:
            self.rect = Rectangle(pos=self.pos, size=self.size)

        with self.canvas.before:
            Color(0, .5, 1, mode='rgb')

        self.bind(pos=self.update_rect)
        self.bind(size=self.update_rect)


        self.add_widget(Label(text='t1'))
        self.text1 = TextInput(multiline=False)
        self.add_widget(self.text1)
        self.add_widget(Label(text='t2'))
        self.text2 = TextInput(multiline=False)
        self.add_widget(self.text2)

        # these bind's don't seem to work
        self.text1.bind(on_touch_down=self.set_focus)
        self.text1.bind(on_touch_up=self.set_focus)
        self.text1.bind(on_touch_move=self.set_focus)


    def set_focus(self):
        print("pressed")
        self.text1.focus = True

    def update_rect(self, *args):
        self.rect.pos = self.pos
        self.rect.size = self.size

I have two problems.

a. The text input is unfocusable.

b. I can't get an event callback (such as on_touch_down) to work on the textinput widget.

Any ideas?

4

2 回答 2

10

Short Answer

You can simple use an Scatter. It includes dragging, rotation and scaling functionality and you can deactivate any or all of them:

my_scatter = Scatter(do_rotation=False, do_scale=False)

None of the problems you described should happen inside a Scatter

Long Answer

Your problem is that you are overriding the on_touch_down, on_touch_move and on_touch_up of the parent.

Normally these methods will call the corresponding ones of the children. For example, when the on_touch_down method of a Widget instance is called, then the Widget instance is going to traverse its children, calling the on_touch_down method of each of then (If you are familiarized with recursion and tree structures, we are talking about a recursive traverse method - I think pre-order - Tree traversal).

This functionality is overridden in the DraggableObject class. You got to be sure to call the method of be base class with:

super(DraggableWidget, self).on_touch_down(touch)

Depending on what is the behaviour you are looking for the methods could look like:

(1) If you always want to call the children:

def on_touch_down( self, touch ):
    if self.collide_point( *touch.pos ):
        touch.grab( self )
    return super(DraggableWidget, self).on_touch_down(touch)

(2) If you just want to call the children when there is no collide:

def on_touch_down( self, touch ):
    if self.collide_point( *touch.pos ):
        touch.grab( self )
        return True      # Don't call the on_touch_down of the Base Class
    return super(DraggableWidget, self).on_touch_down(touch)

And there is more options!. The return value indicates if the event was or not handled by any children. You can, for example, do something like this:

def on_touch_down( self, touch ):
    handled = super(DraggableWidget, self).on_touch_down(touch)
    if not handled and self.collide_point( *touch.pos ):
        touch.grab( self )
        return True
    return handled

In this case, you will avoid the Widget to be dragged when one of the children handle the event. It all depends on what you do.

于 2013-10-08T08:12:54.593 回答
0

Sorry for asking a question here but I think you people can debug this issue . I am not able to solve this issue

KIVY: Carousel inside another carousel

于 2021-01-09T12:07:45.653 回答