automatic text to next line in container in flutter

Using Ellipsis

Text(
  "This is a long text",
  overflow: TextOverflow.ellipsis,
),

Using Fade

Text(
  "This is a long text",
  overflow: TextOverflow.fade,
  maxLines: 1,
  softWrap: false,
),

Using Clip

Text(
  "This is a long text",
  overflow: TextOverflow.clip,
  maxLines: 1,
  softWrap: false,
),

Note:
If you are using Text inside a Row, you can put above Text inside Expanded like:
Expanded(
  child: AboveText(),
)