Does a roth IRA withdrawal affect my ADG?

are you asking about "AGI"?

any dollars that were originally contributed or dollars that were converted from a Trad IRA will not impact your AGI  as it is non-taxable. 

However, if you withdraw "earnings" it may have an impact on AGI as it could be taxable.  If you are over 59.5 years old and the oldest Roth account you own has been open for five calendar years, any earnings withdrawn is not taxable income and would have no impact on AGI.  However, if you are under 59.5 years old OR your oldest Roth account has not been open for five calendar years, the earnings would be taxable and impact AGI.

Note that the IRS presumes that all your contribution dollars are withdrawn first, all your conversion dollars are withdrawn next and your earnings are withdrawn last.