extended_nested_scroll_view

NestedScrollView: extended nested scroll view to fix following issues.

2.inner scrollables in tabview sync issue

3.pull to refresh is not work.

new ExtendedNestedScrollView

Example for issue 1 and Example for issue 2

you only need to care about pinnedHeaderHeight. issue 2 will be handled with keepOnlyOneInnerNestedScrollPositionActive is true.

    var pinnedHeaderHeight =
        //statusBar height
        statusBarHeight +
            //pinned SliverAppBar height in header
            kToolbarHeight;

  child: ExtendedNestedScrollView(
           headerSliverBuilder: (c, f) {
             return buildSliverHeader(false);
           },
           //
           pinnedHeaderSliverHeight: pinnedHeaderHeight,
           keepOnlyOneInnerNestedScrollPositionActive: true,

old ExtendedNestedScrollView

Example for issue 1

give total height of pinned sliver headers in pinnedHeaderSliverHeightBuilder callback

 var tabBarHeight = primaryTabBar.preferredSize.height;
      var pinnedHeaderHeight =
          //statusBar height
          statusBarHeight +
              //pinned SliverAppBar height in header
              kToolbarHeight;

 return NestedScrollView(
        pinnedHeaderSliverHeightBuilder: () {
          return pinnedHeaderHeight;
        },

Example for issue 2

Step1.

Put your list which in tabview into NestedScrollViewInnerScrollPositionKeyWidget,and get unique a key

 return extended.NestedScrollViewInnerScrollPositionKeyWidget(
        widget.tabKey,
        // myRefresh.RefreshIndicator(
        // child:
        ListView.builder(
            itemBuilder: (c, i) {
              return Container(
                //decoration: BoxDecoration(border: Border.all(color: Colors.orange,width: 1.0)),
                alignment: Alignment.center,
                height: 60.0,
                child: Text(widget.tabKey.toString() + ": List$i"),
              );
            },
            itemCount: 100)
        //,
        //onRefresh: onRefresh,
        // )
        );

Step 2

get current tab key in innerScrollPositionKeyBuilder callback. this key should as same as in step 1 given.

 extended.NestedScrollView(
        innerScrollPositionKeyBuilder: () {
          var index = "Tab";
          if (primaryTC.index == 0) {
            index +=
                (primaryTC.index.toString() + secondaryTC.index.toString());
          } else {
            index += primaryTC.index.toString();
          }
          return Key(index);
        },

Example for NestedScrollView pull to refresh

NestedScrollViewRefreshIndicator is as the same as Flutter RefreshIndicator.

 NestedScrollViewRefreshIndicator(
       onRefresh: onRefresh,
       child: extended.NestedScrollView(
         headerSliverBuilder: (c, f) {
           return _buildSliverHeader(primaryTabBar);
         },

Please see the example app of this for a full example.