snapshot.data.docs.length 不适用于 flutter
[英]snapshot.data.docs.length not working on flutter
问题描述
I make some listview and it have likes and comments section.
我做了一些列表视图，它有喜欢和评论部分。 I want to show how many likes and comments that post had.我想显示该帖子有多少喜欢和评论。 The like section works by displaying the number of users who like it, i try to show it with snapshot.data.docs.length.toString() from firestore but when i try to show how many comments with same code as like section it not working and only get 0.类似部分通过显示喜欢它的用户数量来工作，我尝试使用 firestore 中的snapshot.data.docs.length.toString()来显示它，但是当我尝试显示与类似部分具有相同代码的评论数量时，它不会工作，只得到 0。
this is inside comments field这是评论区里面
Padding(
padding: const EdgeInsets.only(top: 8),
child: Padding(
padding: const EdgeInsets.only(left: 15),
child: Row(
mainAxisAlignment:
MainAxisAlignment.spaceEvenly,
children: [
Container(
width: 80.0,
child: Row(
mainAxisAlignment:
MainAxisAlignment.start,
children: [
GestureDetector(
onLongPress: () {
Provider.of<PostFunction>(context,
listen: false)
.showLikes(
context,
documentSnapshot
.data()['title']);
},
onTap: () {
print('Adding like...');
Provider.of<PostFunction>(context,
listen: false)
.addLike(
context,
documentSnapshot
.data()['title'],
Provider.of<AuthenticationService>(
context,
listen: false)
.getUserUid);
},
child: Icon(
FontAwesomeIcons.arrowAltCircleUp,
color: kGreyColor,
size: 18.0,
),
),
StreamBuilder<QuerySnapshot>(
stream: FirebaseFirestore.instance
.collection('posts')
.doc(documentSnapshot
.data()['title'])
.collection('likes')
.snapshots(),
builder: (context, snapshot) {
if (snapshot.connectionState ==
ConnectionState.waiting) {
return Center(
child:
CircularProgressIndicator());
} else {
return Padding(
padding:
const EdgeInsets.only(
left: 8.0),
child: RichText(
text: TextSpan(
text: snapshot
.data.docs.length
.toString(),
style: GoogleFonts
.openSans(
color:
kGreyColor,
fontSize: 16.0),
children: <TextSpan>[
TextSpan(
text: ' votes',
style: GoogleFonts
.openSans(
color:
kGreyColor,
fontSize: 16.0,
)),
]),
),
);
}
})
],
),
),
SizedBox(width: 20),
Container(
width: 150.0,
child: Row(
mainAxisAlignment:
MainAxisAlignment.start,
children: [
GestureDetector(
onTap: () {
Provider.of<PostFunction>(context,
listen: false)
.showComments(
context,
documentSnapshot,
documentSnapshot
.data()['title']);
},
child: Icon(
FontAwesomeIcons.solidComments,
color: kGreyColor,
size: 16.0,
),
),
StreamBuilder<QuerySnapshot>(
stream: FirebaseFirestore.instance
.collection(' posts')
.doc(documentSnapshot
.data()['title'])
.collection('comments')
.snapshots(),
builder: (context, snapshot) {
if (snapshot.connectionState ==
ConnectionState.waiting) {
return Center(
child:
CircularProgressIndicator());
} else {
return Padding(
padding:
const EdgeInsets.only(
left: 8.0),
child: Text(
snapshot.data.docs.length
.toString(),
style: GoogleFonts.openSans(
color: kGreyColor,
fontSize: 16.0),
),
);
}
}),
],
),
),
Spacer(),
Provider.of<AuthenticationService>(context,
listen: false)
.getUserUid ==
documentSnapshot.data()['useruid']
? IconButton(
icon: Icon(EvaIcons.moreVertical,
color: kGreyColor, size: 16),
onPressed: () {
Provider.of<PostFunction>(context,
listen: false)
.showPostOptions(
context,
documentSnapshot
.data()['title']);
})
: Container(width: 0.0, height: 0.0)
],
),
),
),
3 个解决方案
解决方案1
1 已采纳 2021-06-11 10:45:13
Replace.collection(' posts') Replace.collection('posts')
with.collection('posts') with.collection('posts')
in the “comments” section of the Streambuilder.在 Streambuilder 的“评论”部分。
Your stream data is coming as empty as the database cannot find a collection with name (“ posts”).您的 stream 数据为空，因为数据库找不到具有名称的集合（“帖子”）。 So when you try to show how many comments the post had with the same code as the “likes” section it is not working and only getting 0 each time.因此，当您尝试使用与“喜欢”部分相同的代码显示该帖子有多少评论时，它不起作用，每次只能得到 0。
解决方案2
0 2022-03-09 16:06:44
just declare the dataType of builder's arguments..i mean, builder:(BuildContext context,AsyncSnapshot snapShot).只需声明生成器的数据类型 arguments.. 我的意思是，生成器：（BuildContext 上下文，AsyncSnapshot 快照）。 check the image检查图像
解决方案3
-1 2021-08-11 15:06:37
Could you please try this one?你能试试这个吗？
StreamBuilder(
stream: firestoreDB,
builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot) {
if (!snapshot.hasData) {
return Center(child: CircularProgressIndicator());
}
return ListView.builder(
itemCount: snapshot.data!.size,
itemBuilder: (context, index) {
return Card(
child: ListTile(
title: Text(snapshot.data!.docs[index]['name']),
subtitle: Text(snapshot.data!.docs[index]['description']),
),
);
},
);
},
),
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