react native vector icons not displaying code example

Example 1: react native vector icons not showing

add this in '/app/build.gradle'

apply from: "../../node_modules/react-native-vector-icons/fonts.gradle"

Example 2: icon shwoing a box react native vector icons

In 'android/app/build.gradle' (not in android/build.gradle),

apply from: "../../node_modules/react-native-vector-icons/fonts.gradle"

Then,
react-native link react-native-vector-icons 
react-native run-android
react-native start