We had this for ages! I started with her being bare bum in the house for a few weeks. Then tried pants, and the minute she was in pants, she'd just start peeing wherever she was. So it was back to bare bum for another few weeks - trying pants now and again without success. Then one day it just clicked with the pants, but as soon as I put trousers or tights on her we were back to square one.
I remember 4 weeks ago today we were at playgroup and all the other little ones were using the toilet and Sophie had a nappy on because I just couldn't take her into trousers!! But 2 days later, we decided to bite the bullet and try taking her out without a nappy on so she had jeans on and numerous pairs of spare leggings and jeans in my bag, and she had no accidents at all. From that day she has been daytime potty trained - apart from poos, which she has constantly done in her pants up till 2 days ago. I was seriously at my wits' end with the pooing in the pants, she just wasn't getting it at all but the other night she did one in the toilet and yesterday she did one in the potty and she's so excited and pleased with herself I'm hoping we've cracked it!
It honestly will come, it just takes time and patience and it will just click one day xx