Q:

How to figure out why an Android device is not compatible with an APK

In the Google Play Developer Console I can check which devices are compatible/supported for my APK. How do I find out why a device is unsupported?
For example, the Google Nexus 7 "tilapia" and "grouper" are not supported. But Nexus 7, Google Nexus 7 "deb" and Google Nexus 7 "flo" are supported.
Is there a way to know which feature in the manifest is causing the problem?
Features:

android.hardware.CAMERA 
android.hardware.LOCATION
android.hardware.location.GPS 
android.hardware.location.NETWORK
android.hardware.screen.LANDSCAPE
android.hardware.TOUCHSCREEN

API Level 10+

A:

On AndroidManifest.xlm:
    <uses-permission
        android:name="android.permission.CAMERA"
        android:required="false"/>

    <uses-feature
        android:name="android.hardware.camera"
        android:required="false"/>

    <uses-feature
        android:name="android.hardware.camera.front"
        android:required="false"/>

    <uses-feature
        android:name="android.hardware.camera.autofocus"
        android:required="false"/>

This should help. By default, declared permission are required. Nexus 7 (2012) doesn't have front camera, that's why this device isn't compatible.
http://developer.android.com/distribute/googleplay/quality/tablet.html#hardware-requirements

