android - How to check specific features through code? -

here <uses-feature> , <uses-permission> specified in manifest file android application

<uses-feature         android:name="android.hardware.telephony"         android:required="false" />     <uses-feature         android:name="android.hardware.location"         android:required="false" />     <uses-permission android:name="android.permission.call_phone" />     <uses-permission android:name="android.permission.read_contacts" />     <uses-permission android:name="android.permission.read_phone_state" />     <uses-permission android:name="android.permission.process_outgoing_calls" />     <uses-permission android:name="android.permission.modify_phone_state" />     <uses-permission android:name="android.permission.internet" />     <uses-permission android:name="android.permission.access_wifi_state" />     <uses-permission android:name="android.permission.change_wifi_state" />     <uses-permission android:name="android.permission.access_network_state" />     <uses-permission android:name="android.permission.change_network_state" />     <uses-permission android:name="android.permission.access_fine_location" />     <uses-permission android:name="android.permission.access_coarse_location" /> 

i know used specifying required hardware/software features application.also tag filters our application in google play.my application did not show devices including tablets too. have doubts.

1. does happen if specify <uses-permission> without using <uses-feature>?for eg: use permissions call_phone,modify_phone_state etc... without specifying hardware feature android.hardware.telephony

2. my application fired following receivers when click o 2 buttons. how can check these features code?

   android:name="android.intent.action.new_outgoing_call" action android:name="android.intent.action.phone_state"

thanks in advance

(1) need define both <uses-permission /> , <uses-feature /> , set android:required="false" feature. instance

    <uses-permission android:name="android.permission.access_wifi_state" />     <uses-permission android:name="android.permission.change_wifi_state" />     <uses-feature android:name="android.hardware.wifi" android:required="false" /> 

in case permissions feature not required , can check whether available in code. that

(2) should use packagemanager.hassystemfeature() method. instance

    packagemanager mgr = context.getpackagemanager();     boolean hastelephony = mgr.hassystemfeature(packagemanager.feature_telephony);