title: Add dynamically generated hyperlinks in flutter , not using a CONST url?
body: <p>I am hitting the newapi.org to recieve the recent news. I am using these data to create a list view using ListTile. Since each row in list need to have separate hyperlinks which corresponds to that news website, I cannot use a const value. URL launcher is not allowing to have a dynamic value based on index</p>
  
  <p>What I want..</p>
  
  <pre><code>        const url = _newsArticles[index].urlToImage;
          if (await canLaunch(url)) {
            await launch(url);
            } else {
              throw 'Could not launch $url';
               } }), 
  </code></pre>
  
  <p>But it is throwing error</p>
  
  <pre><code>Const variables must be initialized with a constant value.
  Try changing the initializer to be a constant expression.dart(const_initialized_with_non_constant_value).
  </code></pre>
  
  <p>I tried removing the const, but new erros pop up if I do that. I went through some docs of urllauncher, could find anything relevent</p>
  
  <p>Main ListTileCode</p>
  
  <pre><code>         const url = 'https://github.com/ajaytomgeorge';
          if (await canLaunch(url)) {
            await launch(url);
            } else {
              throw 'Could not launch $url';
               } }), 
  
  
  
  
  ListTile _buildItemsForListView(BuildContext context, int index) {
    return ListTile(
  
      leading:ClipRRect(
          borderRadius: BorderRadius.circular(20.0),
          child: Image(
          width: 90.0,
          image: NetworkImage(_newsArticles[index].urlToImage),
          fit: BoxFit.cover,
          ),
          ),
       //_newsArticles[index].urlToImage == null ? Image.asset(Constants.NEWS_PLACEHOLDER_IMAGE_ASSET_URL) : Image.network(_newsArticles[index].urlToImage), 
      subtitle: Text(
        _newsArticles[index].title, 
        style: TextStyle(
          fontSize: 16,
          fontWeight: FontWeight.w600,
          color: Colors.black87,
          )
          ),
      trailing:IconButton(
        icon: Icon(
        FontAwesomeIcons.locationArrow,
        size: 12.0,
        color: Colors.greenAccent,
        ),
        onPressed: () async {
          const url = 'https://github.com/ajaytomgeorge';
          //const url = _newsArticles[index].urlToImage;
          if (await canLaunch(url)) {
            await launch(url);
            } else {
              throw 'Could not launch $url';
               } }),    
  
      isThreeLine: true,
    );
  </code></pre>
  
  <p>}</p>