highlight keywords in string in flutter - flutter

Question

I am new to flutter. I need to highlight keywords in string, normally using replace method we can achieve it but in flutter it seems difficult.
Here is the code I am trying.
Widget getString() {
List<TextSpan> lsTextSpan = [];
String str = 'This is new year and I have new bicycle.';
List<String> lskeywords = ['new year', 'bicycle'];
//here need code ?????
return RichText(
text: TextSpan(
children: lsTextSpan,
));
}

Answer 1

You can change regex pattern as you wish.
RegExp(r'[^a-zA-Z0-9]+') is replacing special characters except 'a-zA-Z0-9'.
RichText(
text: _getText(
text: 'This is new year and I have new bicycle.',
highlightedTextList: ['new', 'bicycle'],
),
),
TextSpan _getText({String text, List<String> highlightedTextList}) {
return TextSpan(
children: _highLight(
text: text,
highlightedTextList: highlightedTextList,
),
);
}
List<TextSpan> _highLight({String text, List<String> highlightedTextList}) {
var splittedText = text.split(' ');
var spans = <TextSpan>[];
var pattern = RegExp(r'[^a-zA-Z0-9]+');
for (var i = 0; i < splittedText.length; i++) {
var index = highlightedTextList.indexWhere((element) {
return splittedText[i].replaceAll(pattern, '') == element;
});
spans.add(
TextSpan(
text: '${splittedText[i]} ',
style: TextStyle(
color: index > -1 ? Colors.blueAccent : Colors.black,
),
),
);
}
return spans;
}
This is the result: