DefaultTextStyle constructor
Creates a default text style for the given subtree.
Consider using DefaultTextStyle.merge to inherit styling information from the current default text style for a given BuildContext.
The style and child arguments are required and must not be null.
The softWrap and overflow arguments must not be null (though they do
have default values).
The maxLines property may be null (and indeed defaults to null), but if
it is not null, it must be greater than zero.
Implementation
const DefaultTextStyle({
Key key,
@required this.style,
this.textAlign,
this.softWrap = true,
this.overflow = TextOverflow.clip,
this.maxLines,
@required Widget child,
}) : assert(style != null),
assert(softWrap != null),
assert(overflow != null),
assert(maxLines == null || maxLines > 0),
assert(child != null),
super(key: key, child: child);