DialogCompat

public static @NonNull View requireViewById(@NonNull Dialog dialog, int id)

Finds the first descendant view with the given ID or throws an IllegalArgumentException if the ID is invalid (< 0), there is no matching view in the hierarchy, or the dialog has not yet been fully created (for example, via show or create).

Note: In most cases -- depending on compiler support -- the resulting view is automatically cast to the target class type. If the target class type is unconstrained, an explicit cast may be necessary.