how to divide a linear layout percentage wise in android xml ? [Android Views/Layouts Properties]

This tutorial explains how you will divide a linear layout percentage wise and allocate space to its child views in percentages. First we divide the layout horizontally and assign space to child views width in percentages. Then the layout is divided vertically and set height of the child views in percentages.
For this android:weightSum and android:layout_weight widget attributes will be used

Key-words: android:weightSum, android:layout_weight, XML, android, layouts