【发布时间】：2021-02-03 14:44:17
【问题描述】：
在我的代码中，我有一个 listview 小部件，我使用 firebase 从 firestore 向它提供数据，并尝试在屏幕上将数据显示为文本。但是什么也没发生，我没有收到任何错误或其他东西。我的页面仍然是空白的。所以谁能告诉我firebase部分或listview之一有错误。这将非常有帮助。
这是我的代码 -
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter/material.dart';
import 'package:social_app/widgets/header.dart';
import 'package:social_app/widgets/progress.dart';
final userRef = FirebaseFirestore.instance.collection("users");
class Timeline extends StatefulWidget {
@override
_TimelineState createState() => _TimelineState();
}
class _TimelineState extends State<Timeline> {
List<dynamic> users = [];
@override
void initState() {
// TODO: implement initState
super.initState();
getUserById();
getUsers();
}
getUserById() {
}
getUsers() async {
final QuerySnapshot snapshot = await userRef.get();
setState(() {
users = snapshot.docs;
});
// snapshot.docs.forEach((DocumentSnapshot doc) {
// print(doc.data());
// print(doc.id);
// print(doc.exists);
// });
}
@override
Widget build(context) {
return SafeArea(
child: Scaffold(
backgroundColor: Colors.black,
appBar: header(context, isAppTitle: true),
body: Container(
child: ListView(
children: users.map((user) => Text(user['username'], style: TextStyle(color: Colors.white),)).toList()
),
),
),
);
}
}
这是我的运行输出 -
Performing hot reload...
Syncing files to device sdk gphone x86...
Reloaded 3 of 800 libraries in 817ms.
W/Firestore( 3283): (21.7.1) [Firestore]: Listen for Query(target=Query(users order by __name__);limitType=LIMIT_TO_FIRST) failed: Status{code=PERMISSION_DENIED, description=Missing or insufficient permissions., cause=null}
E/flutter ( 3283): [ERROR:flutter/lib/ui/ui_dart_state.cc(177)] Unhandled Exception: [cloud_firestore/permission-denied] The caller does not have permission to execute the specified operation.
E/flutter ( 3283): #0 MethodChannelQuery.get (package:cloud_firestore_platform_interface/src/method_channel/method_channel_query.dart:105:7)
E/flutter ( 3283): <asynchronous suspension>
E/flutter ( 3283): #1 Query.get (package:cloud_firestore/src/query.dart:178:25)
E/flutter ( 3283): #2 _TimelineState.getUsers (package:social_app/pages/timeline.dart:29:50)
E/flutter ( 3283): #3 _TimelineState.initState (package:social_app/pages/timeline.dart:22:5)
E/flutter ( 3283): #4 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4765:58)
E/flutter ( 3283): #5 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4601:5)
E/flutter ( 3283): #6 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3569:14)
E/flutter ( 3283): #7 Element.updateChild (package:flutter/src/widgets/framework.dart:3327:18)
E/flutter ( 3283): #8 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:6118:14)
E/flutter ( 3283): #9 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3569:14)
E/flutter ( 3283): #10 Element.updateChild (package:flutter/src/widgets/framework.dart:3327:18)
E/flutter ( 3283): #11 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:6118:14)
E/flutter ( 3283): #12 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3569:14)
E/flutter ( 3283): #13 Element.updateChild (package:flutter/src/widgets/framework.dart:3327:18)
E/flutter ( 3283): #14 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4652:16)
E/flutter ( 3283): #15 Element.rebuild (package:flutter/src/widgets/framework.dart:4343:5)
E/flutter ( 3283): #16 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4606:5)
E/flutter ( 3283): #17 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4601:5)
E/flutter ( 3283): #18 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3569:14)
E/flutter ( 3283): #19 Element.updateChild (package:flutter/src/widgets/framework.dart:3327:18)
E/flutter ( 3283): #20 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4652:16)
E/flutter ( 3283): #21 Element.rebuild (package:flutter/src/widgets/framework.dart:4343:5)
E/flutter ( 3283): #22 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4606:5)
E/flutter ( 3283): #23 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4601:5)
E/flutter ( 3283): #24 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3569:14)
E/flutter ( 3283): #25 Element.updateChild (package:flutter/src/widgets/framework.dart:3327:18)
E/flutter ( 3283): #26 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4652:16)
E/flutter ( 3283): #27 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4800:11)
E/flutter ( 3283): #28 Element.rebuild (package:flutter/src/widgets/framework.dart:4343:5)
E/flutter ( 3283): #29 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4606:5)
E/flutter ( 3283): #30 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4791:11)
E/flutter ( 3283): #31 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4601:5)
E/flutter ( 3283): #32 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3569:14)
E/flutter ( 3283): #33 Element.updateChild (package:flutter/src/widgets/framework.dart:3327:18)
E/flutter ( 3283): #34 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4652:16)
E/flutter ( 3283): #35 Element.rebuild (package:flutter/src/widgets/framework.dart:4343:5)
E/flutter ( 3283): #36 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4606:5)
E/flutter ( 3283): #37 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4601:5)
E/flutter ( 3283): #38 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3569:14)
E/flutter ( 3283): #39 Element.updateChild (package:flutter/src/widgets/framework.dart:3327:18)
E/flutter ( 3283): #40 SliverMultiBoxAdaptorElement.updateChild (package:flutter/src/widgets/sliver.dart:1158:36)
E/flutter ( 3283): #41 SliverMultiBoxAdaptorElement.createChild.<anonymous closure> (package:flutter/src/widgets/sliver.dart:1143:20)
E/flutter ( 3283): #42 BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2683:19)
E/flutter ( 3283): #43 SliverMultiBoxAdaptorElement.createChild (package:flutter/src/widgets/sliver.dart:1136:11)
E/flutter ( 3283): #44 RenderSliverMultiBoxAdaptor._createOrObtainChild.<anonymous closure> (package:flutter/src/rendering/sliver_multi_box_adaptor.dart:350:23)
E/flutter ( 3283): #45 RenderObject.invokeLayoutCallback.<anonymous closure> (package:flutter/src/rendering/object.dart:1883:59)
E/flutter ( 3283): #46 PipelineOwner._enableMutationsToDirtySubtrees (package:flutter/src/rendering/object.dart:915:15)
E/flutter ( 3283): #47 RenderObject.invokeLayoutCallback (package:flutter/src/rendering/object.dart:1883:14)
E/flutter ( 3283): #48 RenderSliverMultiBoxAdaptor._createOrObtainChild (package:flutter/src/rendering/sliver_multi_box_adaptor.dart:339:5)
E/flutter ( 3283): #49 RenderSliverMultiBoxAdaptor.insertAndLayoutLeadingChild (package:flutter/src/rendering/sliver_multi_box_adaptor.dart:455:5)
E/flutter ( 3283): #50 RenderSliverFixedExtentBoxAdaptor.performLayout (package:flutter/src/rendering/sliver_fixed_extent_list.dart:234:32)
E/flutter ( 3283): #51 RenderObject.layout (package:flutter/src/rendering/object.dart:1777:7)
E/flutter ( 3283): #52 RenderSliverEdgeInsetsPadding.performLayout (package:flutter/src/rendering/sliver_padding.dart:132:12)
E/flutter ( 3283): #53 _RenderSliverFractionalPadding.performLayout (package:flutter/src/widgets/sliver_fill.dart:170:11)
E/flutter ( 3283): #54 RenderObject.layout (package:flutter/src/rendering/object.dart:1777:7)
E/flutter ( 3283): #55 RenderViewportBase.layoutChildSequence (package:flutter/src/rendering/viewport.dart:507:13)
E/flutter ( 3283): #56 RenderViewport._attemptLayout (package:flutter/src/rendering/viewport.dart:1561:12)
E/flutter ( 3283): #57 RenderViewport.performLayout (package:flutter/src/rendering/viewport.dart:1470:20)
E/flutter ( 3283): #58 RenderObject._layoutWithoutResize (package:flutter/src/rendering/object.dart:1634:7)
E/flutter ( 3283): #59 PipelineOwner.flushLayout (package:flutter/src/rendering/object.dart:884:18)
E/flutter ( 3283): #60 RendererBinding.drawFrame (package:flutter/src/rendering/binding.dart:436:19)
E/flutter ( 3283): #61 WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:914:13)
E/flutter ( 3283): #62 RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:302:5)
E/flutter ( 3283): #63 SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1117:15)
E/flutter ( 3283): #64 SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1055:9)
E/flutter ( 3283): #65 SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:971:5)
E/flutter ( 3283): #66 _rootRun (dart:async/zone.dart:1190:13)
E/flutter ( 3283): #67 _CustomZone.run (dart:async/zone.dart:1093:19)
E/flutter ( 3283): #68 _CustomZone.runGuarded (dart:async/zone.dart:997:7)
E/flutter ( 3283): #69 _invoke (dart:ui/hooks.dart:251:10)
E/flutter ( 3283): #70 _drawFrame (dart:ui/hooks.dart:209:3)
E/flutter ( 3283):
W/Firestore( 3283): (21.7.1) [WatchStream]: (a99c49e) Stream closed with status: Status{code=CANCELLED, description=Disconnecting idle stream. Timed out waiting for new targets., cause=null}.
W/ansh.social_ap( 3283): Accessing hidden method Ldalvik/system/CloseGuard;->close()V (greylist,core-platform-api, linking, allowed)
【问题讨论】：