Android 9 Development Cookbook - Third Edition

How it works...

When using vertical orientation with LinearLayout, the child Views are created in a single column (stacked on top of each other). The first two Views use the android:layout_height="wrap_content" attribute, giving them a single line each. To specify the height, editTextMessage uses the following:

android:layout_height="0dp" 
android:layout_weight="1" 

When using LinearLayout, it tells Android to calculate the height based on the weight. A weight of 0 (the default if not specified) indicates the View should not expand. In this example, editTextMessage is the only View defined with a weight, so it alone will expand to fill any remaining space in the parent layout.

When using the horizontal orientation, specify android:layout_height="0dp" ...