Sliver 中的 Listview.builder

Question

I had a List of dynamic List of ListTile widgets and I wanted to load it lazily, ie ListTile will be built only when the user scrolls to that position. And I achieved it using ListView.builder() , and it was working fine for me.

But, when I wrapped that ListView.builder() in SliverList using SliverChildListDelegate , the lazy loading property of Listview.builder() is not working any more, now the whole Listview is built during initialization only, instead of being built lazily.

I want lazy loading in Listview.builder() even after wrapping it with SliverList . How can I achieve that?

The code before wrapping into SliverList:-

      ListView.builder(
        itemCount: items.length,
        physics: NeverScrollableScrollPhysics(),
        shrinkWrap: true,
        itemBuilder: (BuildContext context, int index) {
          if (index == 0) return userLocationWidget;
          return ListTile(items[index]);
        },
      ),

The code after warping it into SliverList:-

          SliverList(
            delegate: SliverChildListDelegate(
              [
                ListView.builder(
                  itemCount: items.length + 1,
                  physics: NeverScrollableScrollPhysics(),
                  shrinkWrap: true,
                  padding: const EdgeInsets.all(0.0),
                  itemBuilder: (BuildContext context, int index) {
                    if (index == 0) return userLocationWidget;
                    return makeCard(items[index - 1]);
                  },
                ),
              ],
            ),
          ),

Answer 1

You can used following code:

   SliverList(delegate: SliverChildBuilderDelegate(
          [
           SingleChildScrollView(
              child: Container(
                child:ListView.builder(
                  itemCount: items.length + 1,
                  physics: NeverScrollableScrollPhysics(),
                  shrinkWrap: true,
                  padding: const EdgeInsets.all(0.0),
                  itemBuilder: (BuildContext context, int index) {
                    if (index == 0) return userLocationWidget;
                    return makeCard(items[index - 1]);
                  },
                ),),
            )                   
       ],
    ),
)