Material Design progress indicators display the length of a process or express an unspecified wait time. There are two styles of progress indicators: linear and circular.
This component only provides the circular implementation. See Progress View for the linear implementation.
MDCActivityIndicator is a view that has two modes: indeterminate and determinate. Indeterminate indicators express an unspecified wait time, while determinate indicators represent the length of a process. Activity indicators are indeterminate by default.