Can I track my iPhone if I have the app but it's not logged in?

I lost my iPhone and I have the find my iPhone app but I don't think I'm logged into it from my lost phone.I'm logged into it from my iPad but it says that my iPhone is offline.Is it because it's not logged in or because the person that found it has it turned off?

First of all, you don't the app, go to setting>iCloud>turn find my iPhone on. And if you're logged with iCloud Id and had a pads code then there's no way that someone can open you're iphone. And if fondmyiohone was turned on then uiu just need to download that app "findmyiphone" on any other device, put in you're iCloud and password and just track it. Hope it helps.