How to center a View inside of an Android Layout?

Use ConstraintLayout. Here is an example that will center the view according to the width and height of the parent screen:

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:background="#FF00FF"
        android:orientation="vertical"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintHeight_percent=".6"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintWidth_percent=".4"></LinearLayout>
</android.support.constraint.ConstraintLayout>

You might need to change your gradle to get the latest version of ConstraintLayout:

dependencies {
...
    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
}

I use android:layout_centerInParent="true" and it worked

Use constraint layout. Please refer below code for the same.

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
   xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:app="http://schemas.android.com/apk/res-auto"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   >
       <androidx.appcompat.widget.AppCompatTextView
           android:layout_width="wrap_content"
           android:layout_height="wrap_content"
           app:layout_constraintStart_toStartOf="parent"
           app:layout_constraintTop_toTopOf="parent"
           app:layout_constraintEnd_toEndOf="parent"
           app:layout_constraintBottom_toBottomOf="parent"
           android:textSize="18sp"
           android:textColor="@android:color/holo_orange_dark"
           android:text="Centered TextView"
       />
</androidx.constraintlayout.widget.ConstraintLayout>