You should use a different drive mode for your SDO pin which is currently high impedance. When your button is not pressed the pin's state is not really defined.
Use "Resistive pull up" initially drive High.
Then you read "1" when the button is not pressed and "0" otherwise (when button shorts to GND)
Best practice is to wait until the button is released before proceeding further.
Of curse you will see a random number when you press the button: the loop executes so fast no way to determine the count.
Bob
