Question

我有一个具有多个屏幕的应用程序（pageView + cupertino标签栏）。在几页内，我使用了一个streambuilder。就是这样

class BookList extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return StreamBuilder<QuerySnapshot>(
      stream: Firestore.instance.collection('books').snapshots(),
      builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot) {
        if (snapshot.hasError)
          return new Text('Error: ${snapshot.error}');
        switch (snapshot.connectionState) {
          case ConnectionState.waiting: return new Text('Loading...');
          default:
            return new ListView(
              children: snapshot.data.documents.map((DocumentSnapshot document) {
                return new ListTile(
                  title: new Text(document['title']),
                  subtitle: new Text(document['author']),
                );
              }).toList(),
            );
        }
      },
    );
  }
}

一切正常，但是当我切换页面时（是的，我已经在使用keep client live live混合功能）。半秒钟没有任何响应，然后streambuilder出现了。但是我想在每次streambuilder完成加载时使用淡入淡出的动画使其更“柔和”。

有可能吗？

谢谢！

Answer 1

只要是数据源（Firebase），您只需要在AnimatedSwitcher的builder属性内用StreamBuilder包装最上面的小部件即可实现该淡入动画。

class BookList extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return StreamBuilder<QuerySnapshot>(
      stream: Firestore.instance.collection('books').snapshots(),
      builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot) {
        if (snapshot.hasError)
          return new AnimatedSwitcher(
             duration: Duration(milliseconds: 700),
             child: snapshot.hasData?Text('Error: ${snapshot.error}')):Container();
        switch (snapshot.connectionState) {
          case ConnectionState.waiting: return new Text('Loading...');
          default:
            return new ListView(
              children: snapshot.data.documents.map((DocumentSnapshot document) {
                return new ListTile(
                  title: new Text(document['title']),
                  subtitle: new Text(document['author']),
                );
              }).toList(),
            );
        }
      },
    );
  }
}

Flutter StreamBuilder（Firebase）淡入

1 个答案: