A question on Frequency Hopping

Hi all !
I want to make a slider circling on a frequency band
automatically.
This is the code of original slider, a very simple slider generated by
grc.

class top_block(grc_wxgui.top_block_gui):
def init(self):
grc_wxgui.top_block_gui.init(self, title=“Top
Block”)

            self.variable_slider_0 = variable_slider_0 = 50
            self.samp_rate = samp_rate = 32000

            _variable_slider_0_sizer = wx.BoxSizer(wx.VERTICAL)
            self._variable_slider_0_text_box = forms.text_box(
                    parent=self.GetWin(),
                    sizer=_variable_slider_0_sizer,
                    value=self.variable_slider_0,
                    callback=self.set_variable_slider_0,
                    label='variable_slider_0',
                    converter=forms.float_converter(),
                    proportion=0,
            )
            self._variable_slider_0_slider = forms.slider(
                    parent=self.GetWin(),
                    sizer=_variable_slider_0_sizer,
                    value=self.variable_slider_0,
                    callback=self.set_variable_slider_0,
                    label='variable_slider_0',
                    converter=forms.float_converter(),
                    proportion=0,
            )
            self._variable_slider_0_slider = forms.slider(
                    parent=self.GetWin(),
                    sizer=_variable_slider_0_sizer,
                    value=self.variable_slider_0,
                    callback=self.set_variable_slider_0,
                    minimum=0,
                    maximum=100,
                    num_steps=100,
                    style=wx.SL_HORIZONTAL,
                    cast=float,
                    proportion=1,
            )
            self.Add(_variable_slider_0_sizer)

    def set_variable_slider_0(self, variable_slider_0):
            self.variable_slider_0 = variable_slider_0

self._variable_slider_0_slider.set_value(self.variable_slider_0)

self._variable_slider_0_text_box.set_value(self.variable_slider_0)

    def set_samp_rate(self, samp_rate):
            self.samp_rate = samp_rate

if name == ‘main’:
parser = OptionParser(option_class=eng_option, usage="%prog:
[options]")
(options, args) = parser.parse_args()
tb = top_block()
tb.Run(True)

I want to make some modification on this code to make the slider can
change
frequency automatically and circularly. But some problems trouble me.

  1. I cannot change the parameter ‘*value’ *after it is initialed. I
    think it
    controlled the freq.
  2. When the tb.Run is started, I can’t do anything else.

The problem 1) is the most important one. Please give me some
suggestion.
Thanks very much !
Best wishes for you !