Flutter 颤振-合并仅显示一组值的两条流
我有两条流,我将它们合并如下:Flutter 颤振-合并仅显示一组值的两条流,flutter,dart,Flutter,Dart,我有两条流,我将它们合并如下: Stream<List<QuerySnapshot>> getData() { Stream stream1 = Firestore.instance.collection('datestoremember').document('default').collection('Dates_to_Remember').snapshots(); Stream stream2 = Firestore.instance.collection
Stream<List<QuerySnapshot>> getData() {
Stream stream1 = Firestore.instance.collection('datestoremember').document('default').collection('Dates_to_Remember').snapshots();
Stream stream2 = Firestore.instance.collection('datestoremember').document('Ngrx54m84JbsL0tGvrBeKCBlEnm2').collection('Dates_to_Remember').snapshots();
return StreamZip([stream1, stream2]);
}
Stream getData(){
stream1=Firestore.instance.collection('datestoremember')。document('default')。collection('Dates_to_Memory')。snapshots();
stream2=Firestore.instance.collection('datestoremember')。document('Ngrx54m84JbsL0tGvrBeKCBlEnm2')。collection('Dates_to_memory')。snapshots();
返回StreamZip([stream1,stream2]);
}
然后,我尝试在流生成器中组合这两个流,但结果只有一组值。如果我将流1的名称更改为流2,反之亦然,则会显示另一组值,这表明我在此处合并两个流时存在问题:
child: StreamBuilder(
stream: getData(),
builder: (BuildContext context, AsyncSnapshot<List<QuerySnapshot>> snapshot1) {
List<QuerySnapshot> querySnapshotData = snapshot1.data.toList();
querySnapshotData[0].documents.addAll(querySnapshotData[1].documents);
child:StreamBuilder(
流:getData(),
生成器:(构建上下文上下文,异步快照快照1){
List querySnapshotData=snapshot1.data.toList();
querySnapshotData[0]。documents.addAll(querySnapshotData[1]。documents);
然后我继续使用以下querySnapshotData:
if (querySnapshotData[0].documents.isEmpty)
return Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Center(
child: CircularProgressIndicator(),
)
],
);
if (querySnapshotData[0].documents.length == 0)
return const Center(
child: Text(
"Not Available",
style: TextStyle(fontSize: 30.0, color: Colors.grey),
),
);
return new PageView.builder(
itemCount: querySnapshotData[0].documents.length,
controller: PageController(viewportFraction: 0.5),
onPageChanged: (int index) => setState(() => _index = index),
itemBuilder: (_, i) {
return Transform.scale(
scale: i == _index ? 1 : 0.5,
child: Card(
elevation: 6,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(10)),
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Text(querySnapshotData[0].documents[i]['Date'].toDate().day.toString()),
Text(DateFormat.MMMM()
.format(
formatter.parse(querySnapshotData[0].documents[i]['Date'].toDate().toString()))
.toString()),
Padding(
padding: const EdgeInsets.only(
left: 8.0, right: 8.0),
child: FittedBox(
fit: BoxFit.contain,
child: Text(
querySnapshotData[0].documents[i]['Title'],
overflow: TextOverflow.ellipsis,
),
),
)
],
),
),
);
},
);},
if(querySnapshotData[0].documents.isEmpty)
返回列(
mainAxisAlignment:mainAxisAlignment.center,
儿童:[
居中(
子对象:CircularProgressIndicator(),
)
],
);
if(querySnapshotData[0].documents.length==0)
返回常数中心(
子:文本(
“不可用”,
样式:TextStyle(字体大小:30.0,颜色:Colors.grey),
),
);
返回新的PageView.builder(
itemCount:querySnapshotData[0]。documents.length,
控制器:页面控制器(视口分数:0.5),
onPageChanged:(int index)=>setState(()=>_index=index),
itemBuilder:(u,i){
返回变换比例(
标度:i==\u指数?1:0.5,
孩子:卡片(
标高:6,
形状:圆形矩形边框(
边界半径:边界半径。圆形(10)),
子:列(
mainAxisAlignment:mainAxisAlignment.center,
儿童:[
文本(querySnapshotData[0]。文档[i]['Date'].toDate().day.toString()),
文本(DateFormat.MMMM()
.格式(
parse(querySnapshotData[0]。文档[i]['Date'].toDate().toString())
.toString()),
填充物(
填充:仅限常量边设置(
左:8.0,右:8.0),
孩子:FittedBox(
适合:BoxFit.contain,
子:文本(
querySnapshotData[0]。文档[i]['Title'],
溢出:TextOverflow.省略号,
),
),
)
],
),
),
);
},
);},
首先创建一个var stream1=await Firestore.instance.collection。我已经添加了await并将getData转换为Future,但是现在我在stream:getData()中遇到一个错误,说参数类型“Future”不能分配给参数类型“stream”。