Thanks, @jaimeslo, the problem was I was using the camera microphone.

Noise object gets stuck, and I get no sound.

I ended up copying and pasting from a previous app that was working fine. I cannot say I know what solved the problem, but at least it worked.

I'm not sure about libpd, the app was apparently 32, but I followed the steps found online to make the change and they don't see to do anything.

None. The app is compiled perfectly, it does everything it's supposed to do, but when I upload it to play store, I get this message and doesn't let me upload it.

Probably, @seb-harmonik.ar, I'm not entire sure how to change that. I added
ndk {
abiFilters "armeabi-v7a", "x86", "arm64-v8a", "x86_64"
}
and other variants I found of that I found online, I do see the libraries in the apk analyzer, but I still get the same message.

I'm getting this error message when uploading the app to google play store, do you think it's related to libpd?

Thanks, @bocanegra, I'll give that a try.

I'm sure there is something I'm doing wrong but this takes a whole second to refresh.

Sorry, @bocanegra, I meant [bp~]. I'll try what you suggest. Thanks.

No, @seb-harmonik.ar, I was using [tabwrite~] with the name of the array; but I assuming it will be the same thing. I know that with [pb~]s you can add a message and write the array index you want with no need for bangs (none triggered by the user at least), and I was wondering if that was somehow possible with the [rfft~] object.

Is there another way to pass the numbers from [rfft~] to an array without using [tabwrite~]? I find [tabwrite~] makes the spectrum unstable (maybe something to do with the relationship between the number of bangs and the sampling frequency ... or maybe something else.)

Solved! The problem was apparently you cannot connect [pd~] directly to a message; it has to go through an [env~] first. Thanks, @whale-av.

I have 6 [bp~]s and I want each of one to be represented by a different column in the array going from low to high with the frequency.

Is it possible to pass numbers from a [bp~] to an array using Pd-vanilla? I'm assuming it should be, but all the examples I find are for Pd-Extended and they don't work with vanilla.

I eventually found out what the problem was; neither {sigmund~} nor any other pitch-tracking object are really vanilla objects. I still haven't found a solution though, so any help will be appreciated.

Now I've tried writing the numbers in an array and still, although it works within the patch and although I'm using a readArray function which is almost identical to the one I'm using to read the other array, I'm getting nothing.

I'm trying to get the F0 of a wave to be displayed on the screen of an Android app, so I'm using:
receiver.receiveFloat("sent", f0);
textView.setText(String.valueOf(f0));
And although if I add a receiver within the patch the numbers are indeed received, Android is not really displaying anything.

Thanks for your reply, bocanegra. Eventually, I found out Android allowed me to use a samplerate of 8000Hz and that was low enough to allow me to create a wideband spectrogram (125Hz per band). Thanks to everyone for your replies.

Apparently, it cannot be done, since you can neither force the sampling frequency to be low enough nor the blocksize to be high enough to get a narrow-band spectrogram.