flutter_tracker_wdiget

Description:

flutter tracker wdiget

flutter_tracker_wdiget #
这是一个支持滚动播放和合理曝光的组件
Getting Started #
1、pubspec.yaml
flutter_tracker_wdiget: any
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2、install
flutter pub get
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3、import
import 'package:tracker_scroll_wdiget/tracker_scroll_wdiget.dart'
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4、usage
TrackerScrollWidget(
initialInViewIds: ['0'],
isInViewPortCondition: (
double deltaTop,
double deltaBottom,
double viewPortDimension,
) {
return deltaTop < (0.5 * viewPortDimension) &&
deltaBottom > (0.5 * viewPortDimension);
},
child: ListView.builder(
itemBuilder: (c, index) {
return TrackerItemWidget(
id: '$index',
child: Container(
height: 200,
child: Center(
child: Text(
'$index',
style: TextStyle(color: Colors.white),
)),
),
displayNotifier: (
BuildContext context,
bool visiable,
String id,
) {
print('id:$id - index:$index - visiable:$visiable');
},
builder: (
BuildContext context,
bool isInView,
Widget child,
) {
return Stack(children: [
child,
Positioned(
right: 0,
top: 0,
child: Text(
isInView ? '显示' : '',
style: TextStyle(color: Colors.white),
),
)
]);
},
);
},
itemCount: 100,
),
)
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借鉴于:inview_notifier_list,做了大量修改
不同的地方：
1、在滚动结束才处理cell可见的逻辑，避免滚动中影响性能
2、增加曝光的逻辑，支持滚动过程中只曝光一次或每次都曝光
///跟踪策略
enum TrackerStrategy {
only,

///只有一次
every

///每一次
}

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3、首次进入也会走曝光和inview逻辑
4、更合理的释放机制
5、优化inview_notifier_list逻辑