The weightSum of linear layout (horizontal as an example) defines the maximum weight of the sub-control. If not specified, it is equal to the cumulative sum of layout_weight of all sub-views.
The layout_weight of the subview occupies the proportion of space of the parent view.
Calculation of the true width of a linear layout's subviews:
The width of the subview itself + its own proportion/total proportion * the width of the parent view
Why does the development environment suggest changing width="wrap_content" to 0dp after setting layout_weigth? This eliminates the need to calculate its own width and improves efficiency.