I'm developing an Android app based on NFC technology.
So when my app goes live on the play store, will the app be displayed for people having non-NFC phones? Will they be shown a message like "this app is not supported on your phone" or will they have to face post-installation frustration?
That depends on the app. For using NFC in an app the developer has to declare that in the app's AndroidManifest.xml that is contained it the app (and used by the PlayStore to detect if an app is compatible at all).
When using a feature you can declare if it is required=true or not, if it is not required it is considered optional:
<uses-feature android:name="android.hardware.nfc" android:required="true"/>
Therefore for apps that declare the NFC feature as required=true PlayStore will not show you those apps on a non NFC phone. If it is set to optional (required=false) then you will be able to see this app.
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