My cockapoo Amaya had this problem. She would pull so hard and go crazy whenever see seen anything! It was so annoying because I wanted to have her outside but didnt want people looking at me like I didnt have control. I ended up getting Amaya a shock collar. As horrible as it sounds, it works! Amaya now barks once and gets a warning level 1 shock and nows what happens next if she barks again so she stops and completely forgets about the thing she was barking at. I actually saw her get close to another dog last weekend! It does take time so be consistent. We havent had it for a month yet but we could definitley see that she no longer barks when people come in the house. She still barks at things through the window but it doesnt take long before she remembers. It usually takes a month before your dog learns and wont need the collar anymore. I bought it from Petco for about $45.

I wont lie, its very hard to watch at first but you'll get use to it and see that she brings it upon herself. She wouldnt get hit with the collar's 3rd level shock if she would stop being so stubborn and stop barking on the first shock.

Good luck!