What is android:weightSum in android, and how does it work?

Question

I want to know: What is android:weightSum and layout weight, and how do they work?

Answer 1

One thing which seems like no one else mentioned: let's say you have a vertical LinearLayout, so in order for the weights in layout/element/view inside it to work 100% properly - all of them must have layout_height property (which must exist in your xml file) set to 0dp. Seems like any other value would mess things up in some cases.