Flutter Return Length of Documents from Firebase
up vote
0
down vote
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Im trying to return the length of a list of documents with this function:
Future totalLikes(postID) async {
var respectsQuery = Firestore.instance
.collection('respects')
.where('postID', isEqualTo: postID);
respectsQuery.getDocuments().then((data) {
var totalEquals = data.documents.length;
return totalEquals;
});
}
I'm initialize this in the void init state (with another function call:
void initState() {
totalLikes(postID).then((result) {
setState(() {
_totalRespects = result;
});
});
}
However, when this runs, it initially returns a null value since it doesn't have time to to fully complete. I have tried to out an "await" before the Firestore call within the Future function but get the compile error of "Await only futures."
Can anyone help me understand how I can wait for this function to fully return a non-null value before setting the state of "_totalRespsects"?
Thanks!
firebase 
flutter google-cloud-firestore edited Nov 12 at 2:53
Frank van Puffelen
224k26364390
asked Nov 12 at 2:37
PJQuakJag
629
add a comment |
up vote
0
down vote
favorite
Im trying to return the length of a list of documents with this function:
Future totalLikes(postID) async {
var respectsQuery = Firestore.instance
.collection('respects')
.where('postID', isEqualTo: postID);
respectsQuery.getDocuments().then((data) {
var totalEquals = data.documents.length;
return totalEquals;
});
}
I'm initialize this in the void init state (with another function call:
void initState() {
totalLikes(postID).then((result) {
setState(() {
_totalRespects = result;
});
});
}
However, when this runs, it initially returns a null value since it doesn't have time to to fully complete. I have tried to out an "await" before the Firestore call within the Future function but get the compile error of "Await only futures."
Can anyone help me understand how I can wait for this function to fully return a non-null value before setting the state of "_totalRespsects"?
Thanks!
firebase flutter google-cloud-firestore edited Nov 12 at 2:53
Frank van Puffelen
224k26364390
asked Nov 12 at 2:37
PJQuakJag
629
add a comment |
up vote
0
down vote
favorite
up vote
0
down vote
favorite
Im trying to return the length of a list of documents with this function:
Future totalLikes(postID) async {
var respectsQuery = Firestore.instance
.collection('respects')
.where('postID', isEqualTo: postID);
respectsQuery.getDocuments().then((data) {
var totalEquals = data.documents.length;
return totalEquals;
});
}
I'm initialize this in the void init state (with another function call:
void initState() {
totalLikes(postID).then((result) {
setState(() {
_totalRespects = result;
});
});
}
However, when this runs, it initially returns a null value since it doesn't have time to to fully complete. I have tried to out an "await" before the Firestore call within the Future function but get the compile error of "Await only futures."
Can anyone help me understand how I can wait for this function to fully return a non-null value before setting the state of "_totalRespsects"?
Thanks!
firebase flutter google-cloud-firestore edited Nov 12 at 2:53
Frank van Puffelen
224k26364390
asked Nov 12 at 2:37
PJQuakJag
629
Im trying to return the length of a list of documents with this function:
Future totalLikes(postID) async {
var respectsQuery = Firestore.instance
.collection('respects')
.where('postID', isEqualTo: postID);
respectsQuery.getDocuments().then((data) {
var totalEquals = data.documents.length;
return totalEquals;
});
}
I'm initialize this in the void init state (with another function call:
void initState() {
totalLikes(postID).then((result) {
setState(() {
_totalRespects = result;
});
});
}
However, when this runs, it initially returns a null value since it doesn't have time to to fully complete. I have tried to out an "await" before the Firestore call within the Future function but get the compile error of "Await only futures."
Can anyone help me understand how I can wait for this function to fully return a non-null value before setting the state of "_totalRespsects"?
Thanks!
firebase flutter google-cloud-firestore firebase flutter google-cloud-firestore edited Nov 12 at 2:53
Frank van Puffelen
224k26364390
asked Nov 12 at 2:37
PJQuakJag
629
edited Nov 12 at 2:53
Frank van Puffelen
224k26364390
asked Nov 12 at 2:37
PJQuakJag
629
edited Nov 12 at 2:53
Frank van Puffelen
224k26364390
edited Nov 12 at 2:53
Frank van Puffelen
224k26364390
edited Nov 12 at 2:53
Frank van Puffelen
224k26364390
224k26364390
asked Nov 12 at 2:37
PJQuakJag
629
asked Nov 12 at 2:37
PJQuakJag
629
asked Nov 12 at 2:37
PJQuakJag
629
629
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
up vote
2
down vote
accepted
I think you're looking for this:
Future totalLikes(postID) async {
var respectsQuery = Firestore.instance
.collection('respects')
.where('postID', isEqualTo: postID);
var querySnapshot = await respectsQuery.getDocuments();
var totalEquals = querySnapshot.documents.length;
return totalEquals;
}
Note that this loads all documents, just to determine the number of documents, which is incredibly wasteful (especially as you get more documents). Consider keeping a document where you maintain the count as a field, so that you only have to read a single document to get the count. See aggregation queries and distributed counters in the Firestore documentation.
answered Nov 12 at 2:57
Frank van Puffelen
224k26364390
Thanks, Frank! And thanks for tip on aggregation queries and distributed counters. This seems like exactly what I need. Any chance you have any good examples of Flutter implementation of these? Appreciate the help.
– PJQuakJag
Nov 12 at 17:07
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
2
down vote
accepted
I think you're looking for this:
Future totalLikes(postID) async {
var respectsQuery = Firestore.instance
.collection('respects')
.where('postID', isEqualTo: postID);
var querySnapshot = await respectsQuery.getDocuments();
var totalEquals = querySnapshot.documents.length;
return totalEquals;
}
Note that this loads all documents, just to determine the number of documents, which is incredibly wasteful (especially as you get more documents). Consider keeping a document where you maintain the count as a field, so that you only have to read a single document to get the count. See aggregation queries and distributed counters in the Firestore documentation.
answered Nov 12 at 2:57
Frank van Puffelen
224k26364390
Thanks, Frank! And thanks for tip on aggregation queries and distributed counters. This seems like exactly what I need. Any chance you have any good examples of Flutter implementation of these? Appreciate the help.
– PJQuakJag
Nov 12 at 17:07
add a comment |
up vote
2
down vote
accepted
I think you're looking for this:
Future totalLikes(postID) async {
var respectsQuery = Firestore.instance
.collection('respects')
.where('postID', isEqualTo: postID);
var querySnapshot = await respectsQuery.getDocuments();
var totalEquals = querySnapshot.documents.length;
return totalEquals;
}
Note that this loads all documents, just to determine the number of documents, which is incredibly wasteful (especially as you get more documents). Consider keeping a document where you maintain the count as a field, so that you only have to read a single document to get the count. See aggregation queries and distributed counters in the Firestore documentation.
answered Nov 12 at 2:57
Frank van Puffelen
224k26364390
Thanks, Frank! And thanks for tip on aggregation queries and distributed counters. This seems like exactly what I need. Any chance you have any good examples of Flutter implementation of these? Appreciate the help.
– PJQuakJag
Nov 12 at 17:07
add a comment |
up vote
2
down vote
accepted
up vote
2
down vote
accepted
I think you're looking for this:
Future totalLikes(postID) async {
var respectsQuery = Firestore.instance
.collection('respects')
.where('postID', isEqualTo: postID);
var querySnapshot = await respectsQuery.getDocuments();
var totalEquals = querySnapshot.documents.length;
return totalEquals;
}
Note that this loads all documents, just to determine the number of documents, which is incredibly wasteful (especially as you get more documents). Consider keeping a document where you maintain the count as a field, so that you only have to read a single document to get the count. See aggregation queries and distributed counters in the Firestore documentation.
answered Nov 12 at 2:57
Frank van Puffelen
224k26364390
I think you're looking for this:
Future totalLikes(postID) async {
var respectsQuery = Firestore.instance
.collection('respects')
.where('postID', isEqualTo: postID);
var querySnapshot = await respectsQuery.getDocuments();
var totalEquals = querySnapshot.documents.length;
return totalEquals;
}
Note that this loads all documents, just to determine the number of documents, which is incredibly wasteful (especially as you get more documents). Consider keeping a document where you maintain the count as a field, so that you only have to read a single document to get the count. See aggregation queries and distributed counters in the Firestore documentation.
answered Nov 12 at 2:57
Frank van Puffelen
224k26364390
answered Nov 12 at 2:57
Frank van Puffelen
224k26364390
answered Nov 12 at 2:57
Frank van Puffelen
224k26364390
answered Nov 12 at 2:57
Frank van Puffelen
224k26364390
224k26364390
Thanks, Frank! And thanks for tip on aggregation queries and distributed counters. This seems like exactly what I need. Any chance you have any good examples of Flutter implementation of these? Appreciate the help.
– PJQuakJag
Nov 12 at 17:07
add a comment |
Thanks, Frank! And thanks for tip on aggregation queries and distributed counters. This seems like exactly what I need. Any chance you have any good examples of Flutter implementation of these? Appreciate the help.
– PJQuakJag
Nov 12 at 17:07
Thanks, Frank! And thanks for tip on aggregation queries and distributed counters. This seems like exactly what I need. Any chance you have any good examples of Flutter implementation of these? Appreciate the help.
– PJQuakJag
Nov 12 at 17:07
Thanks, Frank! And thanks for tip on aggregation queries and distributed counters. This seems like exactly what I need. Any chance you have any good examples of Flutter implementation of these? Appreciate the help.
– PJQuakJag
Nov 12 at 17:07
add a comment |
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