我有一個 Future 函式可以從 Firebase 獲取資料，這不是正確的空查詢：
Future getProducts(vendorId) async {
await vendorsInfoColl.doc(vendorId)
.collection("products")
.get()
.then((QuerySnapshot querySnapShot) async {
if (querySnapShot.docs.isNotEmpty){
print('not empty');
print(querySnapShot.docs);
return querySnapShot.docs;
} else {
print('snapshot empty');
return null;
}
});
}
我只是很難讓 FutureBuilder 看到它。一直說有空資料。
Widget build(BuildContext context) {
return AlertDialog(
// pull title from db
// title: Future Text(vendorTitle.toString()),
title: Text(vendorTitle.toString()),
content: FutureBuilder(
future: VendorDatabase().getProducts(widget.vendorId),
builder: (BuildContext context, AsyncSnapshot snapshot) {
print(snapshot.connectionState);
if (snapshot.connectionState == ConnectionState.waiting) {
return CircularProgressIndicator();
} else if (snapshot.connectionState == ConnectionState.done) {
if (snapshot.hasError) {
return const Text('Error');
} else if (snapshot.hasData) {
var blabla = snapshot.data;
print('there is snapshot data: $blabla');
return ListView.builder(
itemCount: 3,
itemBuilder: (context, index) {
return ListTile(
title: Text(blabla['products']) //<-- i know this is wrong but can't fixt it till future builder actually sees some data.
);
}
);
} else {
return const Text('Empty data');
}
} else {
return Text('State: ${snapshot.connectionState}');
}
}
)
);
}
如果還能得到一些關于如何將其放入串列的提示，那就太好了:)
uj5u.com熱心網友回復：
你沒有在里面回傳任何東西getProducts：
Future getProducts(vendorId) async {
return await vendorsInfoColl.doc(vendorId)
.collection("products")
.get()
.then((QuerySnapshot querySnapShot) async {
if (querySnapShot.docs.isNotEmpty){
return querySnapShot.docs;
} else {
return null;
}
});
}
為了避免將來發生這種情況，請在您的 Future 中宣告一個型別：
// vvvvvvvvvvvvvvvv
Future<List<Document>> getProducts(vendorId) async {
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標籤：火力基地 扑 谷歌云firestore