import datetime, ui

class ScreenshotView(ui.View):
    def __init__(self):
        self.width = 300
        self.add_subview(self.make_button())
        self.add_subview(self.make_textview())
        self.present('sheet')

    def get_shapshot(self):
        with ui.ImageContext(self.width, self.height) as context:
                self.draw_snapshot()
                return context.get_image()

    def screenshot_action(self, sender):
        print('Saving screenshots at:')
        for i in xrange(3):  # save three screenshots in a row
            now = str(datetime.datetime.now())
            print('> ' + now)
            self['textfield'].text = now
            filename = 'Screenshot_{}.png'.format(now.replace(' ', '_'))
            with open(filename, 'wb') as out_file:
                out_file.write(self.get_shapshot().to_png())

    def make_button(self):
        button = ui.Button(name='button', title='Save three screenshots')
        button.action = self.screenshot_action
        button.width  = self.width
        return button

    def make_textview(self):
        tf = ui.TextField(name='textfield', frame=self.bounds)
        offset = self['button'].height
        tf.y      += offset
        tf.height -= offset
        tf.border_color = (0, 0, 1)
        tf.border_width = 2
        tf.alignment = ui.ALIGN_CENTER
        tf.text = str(datetime.datetime.now())
        return tf

view = ScreenshotView()

Create ScreenshotView.py