One app I use is Bitcoin Address Watcher.
I have all my loaded btc public addresses on it and if any changes take place I get an alert right away.
Edit..it seems the app I suggested is no longer available on playstore..but there is wallet watcher as a good alternative. Not sure if it has an alarm feature though
This app sounds really interesting. I did a quick search but did not find any info about it. - Is it secure to use or do they submit the pub key data to their servers or something like that?
What I am wondering is the following: if someone gets hold of your pub key collection he has a full view of your (BTC) finances, right? So in order to make this a secure app it would need some pw protection and also guarantee that no data is kept outside your local device.
/Sorry for ot, but maybe this info is interesting to some, otherwise we can continue the chat via dm, if OP preferes that.
Yes they stopped listing it on Google playstore no idea why. This is what I found on a google search
Add a Bitcoin address and get notifications whenever transactions happen. You can add as many addresses as you want, both "normal" and "pay to script hash" (P2SH) addresses are supported. No private key required. Bitcoin Address Watcher was tested and optimised for low battery and network usage. No idea about its privacy as far as the questions you ask. They are good. But it does not mean what I am following belongs to me. I can be following any public address just for the sake of following it.
There other out there besides this one btw.
I have also asked a forum member who is a great programmer to perhaps come up his own app that can do the same.
It is great to have especially when you can set it to give you an alert that there has been btc movement in a public address you are following.
It wont be the greatest alarm you ever wanna hear trust me! Its with dread when you see it come up as you know that something is not right!