As an alternative to writing XML layout resource files or using the Android Studio Layout Editor tool, Android user interfaces may also be dynamically created in Java code.
Creating layouts in Java code consists of creating instances of view classes and setting attributes on those objects to define required appearance and behavior.
How a view is positioned and sized relative to its ConstraintLayout parent view and any sibling views is defined through the use of constraint sets. A constraint set is represented by an instance of the ConstraintSet class which, once created, can be configured using a wide range of method calls to perform tasks such as establishing constraint connections, controlling view sizing behavior and creating chains.
With the basics of the ConstraintSet class covered in this chapter, the next chapter will work through a tutorial that puts these features to practical use.
