方法toArray（）不在列表上工作

I'm trying to convert a list to an array, but I get an error and I can't figure out why. I'm taking the current hour and in a for loop I get the rest of the hours of today and put it in a list. When i try to change it to an array I get an error. I try to do this because later I use that array in a I'm trying to convert a list to an array, but I