title: Change List Tile trailing using provider
body: <p>The problem is that when a List Tile is tapped the quantity is incremented for all the list tiles.</p>
  <p>I have a stateless widget which has this build method :</p>
  <pre><code>final ProductsList productsList = ProductsList(context);
  return Scaffold(
          body: Center(child: productWidget(productsList, args)));
    }
  </code></pre>
  <p>This is the ProductWidget</p>
  <pre><code>
    FutureBuilder productWidget(productsList) {
      return FutureBuilder(
        future: getProducts,
        builder: (context, products) {
          switch (products.connectionState) {
            case ConnectionState.waiting:
              return Text('Loading....');
            default:
              return Scaffold(
                  body: productsList.build(products.data));
          }
        },
      );
  </code></pre>
  <p>And this is what productsList.build does:</p>
  <pre><code>  ProductsList(this.context);
  
    Padding getProduct(name) {
      int _quantity = Provider.of&lt;Quantity&gt;(context).getQuantity();
      return ListTile(
          key: UniqueKey(),
          onTap: () {
            Provider.of&lt;Quantity&gt;(context, listen: false).incrementQuantity();
          },
          title: Text(name),
          trailing: Text(&quot;$_quantity&quot;),
        ),
      );
    }
  
    ListView build(products) {
      List&lt;Widget&gt; _products = new List();
  
      for (var i = 0; i &lt; products.length; i++) {
        _products.add(getProduct(products[i].name));
      }
  
      return ListView(
        children: _products,
      );
    }
  </code></pre>
  <p>and I am using this changeNotifier :</p>
  <pre><code>
  class Quantity extends ChangeNotifier {
    int _quantity = 0;
  
    void incrementQuantity(){
      _quantity += 1;
      notifyListeners();
    }
  
    int getQuantity() {
      return _quantity;
    }
  }
  
  </code></pre>
  <p>I want to tap a list tile and increment just it's value which is displayed in the trailing, but not of the others.</p>
  <p>I am using multi-provider in the main file of the application.</p>