Flutter if conditions?

I am making a tic tac toe in which i have executed a lot of if statements and one else statement for draw .

But the problem is that the code is running good in every condition but whenever there is no fields left in tic tac toe and the winner is x or o the program shows a dialog showing x or o a winner and right after it shows draw dialog .

I think its executing two statements at once :

1. if statement is true
2. else if statement when it true

Does it even happen ? Help me flutter