滚动完成回调

Question

我正在尝试听滚动整理，但是到目前为止，我还没有找到在线解决方案。有什么建议吗？

Answer 1

您可以使用NotificationListener包装Scaffold，ListView或GridView
滚动完成后，您将收到ScrollEndNotification
您可以在

下复制粘贴运行完整代码

ListView演示的代码段

NotificationListener<ScrollNotification>(
              onNotification: (scrollNotification) {
                if (scrollNotification is ScrollStartNotification) {
                  setState(() {
                    message = "Scroll Start";
                  });
                } else if (scrollNotification is ScrollUpdateNotification) {
                  setState(() {
                    message = "Scroll Update";
                  });
                } else if (scrollNotification is ScrollEndNotification) {
                  setState(() {
                    message = "Scroll End";
                  });
                }
              },
              child: ListView.builder(
                itemCount: 30,
                itemBuilder: (context, index) {
                  return ListTile(title: Text("Index : $index"));
                },
              ),
            )

工作演示

完整代码

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
      ),
      home: ScrollStatus(),
    );
  }
}


class ScrollStatus extends StatefulWidget {
  @override
  _ScrollStatusState createState() => _ScrollStatusState();
}

class _ScrollStatusState extends State<ScrollStatus> {
  String message = "";

  _onStartScroll(ScrollMetrics metrics) {
    setState(() {
      message = "Scroll Start";
    });
  }

  _onUpdateScroll(ScrollMetrics metrics) {
    setState(() {
      message = "Scroll Update";
    });
  }

  _onEndScroll(ScrollMetrics metrics) {
    setState(() {
      message = "Scroll End";
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("Scroll Status"),
      ),
      body: Column(
        children: <Widget>[
          Container(
            height: 50.0,
            color: Colors.green,
            child: Center(
              child: Text(message),
            ),
          ),
          Expanded(
            child: NotificationListener<ScrollNotification>(
              onNotification: (scrollNotification) {
                if (scrollNotification is ScrollStartNotification) {
                  _onStartScroll(scrollNotification.metrics);
                } else if (scrollNotification is ScrollUpdateNotification) {
                  _onUpdateScroll(scrollNotification.metrics);
                } else if (scrollNotification is ScrollEndNotification) {
                  _onEndScroll(scrollNotification.metrics);
                }
              },
              child: ListView.builder(
                itemCount: 30,
                itemBuilder: (context, index) {
                  return ListTile(title: Text("Index : $index"));
                },
              ),
            ),
          ),
        ],
      ),
    );
  }
}