text: touch_began no longer called for ui.View derived class using Pythonista beta.
  Can you try eliminating the imageview? I think the imageview might be stealing your touches. You may need to set imageview.touch_enabled=False.
  Also you may need to set touch_enabled=True on the custom view.
  @technoway, one thing, that might have been introduced in some new version, is that a ui.View with no background color set will not get any touch events.
  with Pythonista 3.2 +
  #... self.iv.image = ui.Image.named('lock_screen.png') def draw(self): self.iv.image.draw() #...
  it worked for me
  edit: btw. leave out the ImageView is also possible
  #... #self.iv = ImageView() #self.iv... self.image = ui.Image.named('lock_screen.png') def draw(self): self.image.draw() #....
  def draw(self): self.iv.image.draw(0,0,self.width,self.height)
  you can only fit your image or you might like to calculate the screen ratio first...