Flutter 图像未从Flatter应用程序中的firestore加载
我对弗利特和Firestore很陌生。所以我在Firebase存储上上传了一些照片。 然后我将他们的下载URL粘贴到firestore数据库中。 但每次我尝试在我的应用程序中获取它们时，我都会遇到以下错误 ════════ widgets库捕获到异常═══════════════════════════════════ 'package:flatter/src/painting/_network\u image\u io.dart'：失败的断言：第26行位置14:'url！=null”：不正确。 导致错误的相关小部件已被删除 未来建设者 但其他数据正在读取并显示在小部件中。 这是我的密码：Flutter 图像未从Flatter应用程序中的firestore加载,flutter,flutter-futurebuilder,Flutter,Flutter Futurebuilder,我对弗利特和Firestore很陌生。所以我在Firebase存储上上传了一些照片。 然后我将他们的下载URL粘贴到firestore数据库中。 但每次我尝试在我的应用程序中获取它们时，我都会遇到以下错误 ════════ widgets库捕获到异常═══════════════════════════════════ 'package:flatter/src/painting/_network\u image\u io.dart'：失败的断言：第26行位置14:'url！=null”：不正
import 'package:flutter/material.dart';
import 'package:hexcolor/hexcolor.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:dotted_line/dotted_line.dart';
class CourseList extends StatefulWidget {
@override
_CourseListState createState() => _CourseListState();
}
class _CourseListState extends State<CourseList> {
@override
Widget build(BuildContext context) {
return FutureBuilder(
future: FirebaseFirestore.instance
.collection('students')
.doc(FirebaseAuth.instance.currentUser.uid)
.get(),
builder: (BuildContext context, snapshot) {
if (snapshot.hasData) {
Map<String, dynamic> documentFields = snapshot.data.data();
return ListView(
shrinkWrap: true,
children: [
Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Stack(
overflow: Overflow.visible,
children: [
Positioned(
// top: 0,
child: Padding(
padding: const EdgeInsets.fromLTRB(0, 10, 0, 0),
child: Container(
width: 430,
height: 230,
decoration: BoxDecoration(
image: DecorationImage(
image: AssetImage("assets/hero.png"),
fit: BoxFit.cover,
),
),
),
),
),
Positioned(
top: 200,
left: 20,
right: 20,
child: Card(
color: Hexcolor('#3B3E43'),
elevation: 10,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(10.0),
),
child: Padding(
padding: const EdgeInsets.all(15),
child: Column(
children: [
Text(
'Welcome to Class Information System',
textAlign: TextAlign.center,
style: TextStyle(
color: Colors.white,
fontFamily: 'ProductSans',
fontSize: 16,
fontWeight: FontWeight.bold,
),
),
SizedBox(
height: 10,
),
Text(
'UTM Class Management system offers UTM students a varity of features such as, managing and making real time class schedule, finding class venue with dynamic maps and finding all the lecturers office, phone and email all at one place!',
textAlign: TextAlign.center,
style: TextStyle(
color: Colors.grey[300],
fontFamily: 'ProductSans',
fontSize: 11,
),
),
SizedBox(
height: 15,
),
Column(
children: [
Row(
mainAxisAlignment:
MainAxisAlignment.spaceEvenly,
children: [
Image.asset(
'assets/001-school.png',
scale: 8,
),
SizedBox(
width: 0,
),
Image.asset(
'assets/002-teacher.png',
scale: 8,
),
SizedBox(
width: 0,
),
Image.asset(
'assets/003-calendar.png',
scale: 8,
),
],
),
SizedBox(
height: 10,
),
Row(
mainAxisAlignment:
MainAxisAlignment.spaceEvenly,
children: [
Text(
'Finding class\nvenue with\ndynamic maps',
textAlign: TextAlign.center,
style: TextStyle(
color: Colors.grey[300],
fontFamily: 'ProductSans',
fontSize: 10,
),
),
Text(
'Finding all the\nlecturers informations\nat one place!',
textAlign: TextAlign.center,
style: TextStyle(
color: Colors.grey[300],
fontFamily: 'ProductSans',
fontSize: 10,
),
),
Text(
'Make & Edit\nreal time\nclass schedule',
textAlign: TextAlign.center,
style: TextStyle(
color: Colors.grey[300],
fontFamily: 'ProductSans',
fontSize: 10,
),
),
],
),
],
)
],
),
),
),
),
],
),
SizedBox(
height: 220,
),
Padding(
padding: const EdgeInsets.fromLTRB(25, 10, 0, 0),
child: Text(
'Courses Taken',
textAlign: TextAlign.left,
style: TextStyle(
color: Hexcolor('#E69405'),
fontFamily: 'ProductSans',
fontSize: 18,
),
),
),
Padding(
padding: const EdgeInsets.fromLTRB(25, 10, 25, 5),
child: DottedLine(
direction: Axis.horizontal,
lineLength: double.infinity,
lineThickness: 1.0,
dashLength: 4.0,
dashColor: Hexcolor('#707070'),
dashRadius: 0.0,
dashGapLength: 6.0,
dashGapColor: Colors.transparent,
dashGapRadius: 0.0,
),
),
SizedBox(
height: 15,
),
Card(
color: Hexcolor('#3B3E43'),
elevation: 10,
margin: EdgeInsets.fromLTRB(25, 0, 25, 20),
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(10.0),
),
child: Padding(
padding: const EdgeInsets.all(15),
child: ListView(
physics: ClampingScrollPhysics(),
shrinkWrap: true,
children: [
Row(
children: [
Expanded(
child: Padding(
padding:
const EdgeInsets.fromLTRB(10, 0, 0, 0),
child: CircleAvatar(
backgroundImage:
NetworkImage(documentFields['img1']),
radius: 28,
),
),
),
Expanded(
flex: 4,
child: Padding(
padding:
const EdgeInsets.fromLTRB(20, 0, 0, 0),
child: RichText(
text: TextSpan(
style: TextStyle(
fontFamily: 'ProductSans',
fontSize: 17,
),
text: documentFields['course1'],
children: <TextSpan>[
TextSpan(
text:
'\nSection: ${documentFields['section1']}',
style: TextStyle(
fontFamily: 'ProductSans',
fontSize: 14,
color: Colors.grey[400],
),
),
],
),
),
),
),
],
),
SizedBox(
height: 15,
),
DottedLine(
direction: Axis.horizontal,
lineLength: double.infinity,
lineThickness: 1.0,
dashLength: 10,
dashColor: Hexcolor('#707070'),
dashRadius: 0.0,
dashGapLength: 0,
dashGapColor: Colors.transparent,
dashGapRadius: 0.0,
),
SizedBox(
height: 15,
),
Row(
children: [
Expanded(
child: Padding(
padding:
const EdgeInsets.fromLTRB(10, 0, 0, 0),
child: CircleAvatar(
child: Image.network(
'${documentFields['img2']}'),
radius: 28,
),
),
),
Expanded(
flex: 4,
child: Padding(
padding:
const EdgeInsets.fromLTRB(20, 0, 0, 0),
child: RichText(
text: TextSpan(
style: TextStyle(
fontFamily: 'ProductSans',
fontSize: 17,
),
text: documentFields['course2'],
children: <TextSpan>[
TextSpan(
text:
'\nSection: ${documentFields['section2']}',
style: TextStyle(
fontFamily: 'ProductSans',
fontSize: 14,
color: Colors.grey[400],
),
),
],
),
),
),
),
],
),
SizedBox(
height: 15,
),
DottedLine(
direction: Axis.horizontal,
lineLength: double.infinity,
lineThickness: 1.0,
dashLength: 10,
dashColor: Hexcolor('#707070'),
dashRadius: 0.0,
dashGapLength: 0,
dashGapColor: Colors.transparent,
dashGapRadius: 0.0,
),
SizedBox(
height: 15,
),
Row(
children: [
Expanded(
child: Padding(
padding:
const EdgeInsets.fromLTRB(10, 0, 0, 0),
child: CircleAvatar(
child: Image.network(
'${documentFields['img3']}'),
radius: 28,
),
),
),
Expanded(
flex: 4,
child: Padding(
padding:
const EdgeInsets.fromLTRB(20, 0, 0, 0),
child: RichText(
text: TextSpan(
style: TextStyle(
fontFamily: 'ProductSans',
fontSize: 17,
),
text: documentFields['course3'],
children: <TextSpan>[
TextSpan(
text:
'\nSection: ${documentFields['section3']}',
style: TextStyle(
fontFamily: 'ProductSans',
fontSize: 14,
color: Colors.grey[400],
),
),
],
),
),
),
),
],
),
SizedBox(
height: 15,
),
DottedLine(
direction: Axis.horizontal,
lineLength: double.infinity,
lineThickness: 1.0,
dashLength: 10,
dashColor: Hexcolor('#707070'),
dashRadius: 0.0,
dashGapLength: 0,
dashGapColor: Colors.transparent,
dashGapRadius: 0.0,
),
SizedBox(
height: 15,
),
Row(
children: [
Expanded(
child: Padding(
padding:
const EdgeInsets.fromLTRB(10, 0, 0, 0),
child: CircleAvatar(
child: Image.network(
'${documentFields['img4']}'),
radius: 28,
),
),
),
Expanded(
flex: 4,
child: Padding(
padding:
const EdgeInsets.fromLTRB(20, 0, 0, 0),
child: RichText(
text: TextSpan(
style: TextStyle(
fontFamily: 'ProductSans',
fontSize: 17,
),
text: documentFields['course4'],
children: <TextSpan>[
TextSpan(
text:
'\nSection: ${documentFields['section4']}',
style: TextStyle(
fontFamily: 'ProductSans',
fontSize: 14,
color: Colors.grey[400],
),
),
],
),
),
),
),
],
),
],
),
),
)
],
),
],
);
}
return Center(child: CircularProgressIndicator());
},
);
}
}
任何帮助都将不胜感激。谢谢 尝试在控制台中打印图像URL以确保其值。
错误是它的值为空，因此您可能没有正确写入图像URL的键映射键。因此，我终于找到了答案。如果有人在寻找答案。您所要做的就是，在firebase存储中存储图像后，您必须复制存储位置而不是下载URL，然后将其放入firestore中。然后使用firebase图像提供程序包在应用程序中调用它
child: ListTile(
leading: CircleAvatar(
radius: 25,
backgroundImage: FirebaseImage(coffee.img),
),
是的，它在控制台中打印空值，如何解决此问题？首先要做的是按照我告诉你的做，在Firestore中检查密钥名称，并在Flatter应用程序的地图中匹配它。仍然是空值。当我从firestore复制url并将其粘贴到网络图像中时，它会显示图像，但在此处返回空值。如果您手动设置url字符串，您的代码是否正常工作？是的，它正常工作。我发现在这方面存在类似的代码问题