#拖拽
if event is InputEventMouseButton:
		if (event.position - $Sprite2D.position).length() <click_radius and not dragging and event.pressed:
			dragging=true
			print(1)
		if dragging and not event.pressed:
			dragging = false
			print(2)
	if dragging:
		$Sprite2D.position = event.position

if event.is_action_pressed("shubiao_left"):为啥不用鼠标事件呢，？因为鼠标事件没有 not event.pressed 不能松开后 dragging=false