Flutter/Dart: 无法在屏幕上刷新RefreshIndicator数据

huangapple
go评论133阅读模式
英文:

Flutter/Dart: Not able to refresh RefreshIndicator data on screen

问题

我尝试使用RefreshIndicator从数据库中重新加载数据。在超出滚动时，可以从数据库中读取数据，但不知何故无法刷新屏幕上的数据。我是否遗漏或弄错了什么？

  1.    Future<void> getMTMavailableamount1() async {
  2.         final temp = ModelsPositions().getMasterPositions();
  3.         setState() {
  4.           _futureList = temp;
  5.         }
  6.     }
  8.     @override
  9.     Widget build(BuildContext context) {
  10.         return Scaffold(
  11.             appBar: AppBar(
  12.               title: const Text('Master Control'),
  13.               centerTitle: true,
  14.             ),
  15.             body: RefreshIndicator(
  16.               onRefresh: getMTMavailableamount1,
  17.               child: FutureBuilder<List<dynamic>>(
  18.                 future: _futureList,
  19.                 builder: (context, snapshot) {
  20.                   if (snapshot.hasData) {
  21.                     List<dynamic> positions = snapshot.data ?? [];
  22.                     return ListView.builder(
  23.                       itemCount: positions.length,
  24.                       itemBuilder: (context, index) {
  25.                         String custID = positions[index][0];
  26.                         String custName = positions[index][1];
  27.                         double m2m = double.parse(positions[index][2]);
  28.                         double available = double.parse(positions[index][3]);
英文:

I'm trying to reload data from DB with RefreshIndicator. Upon over-scroll, Able to read data from DB but somehow not able to refresh the data on the screen. Did i miss/mess up anything?

  1.  Future&lt;void&gt; getMTMavailableamount1() async {
  2.     final temp = ModelsPositions().getMasterPositions();
  3.     setState() {
  4.       _futureList = temp;
  5.     }
  6.   }
  8. @override
  9.   Widget build(BuildContext context) {
  10.     return Scaffold(
  11.         appBar: AppBar(
  12.           title: const Text(&#39;Master Control&#39;),
  13.           centerTitle: true,
  14.         ),
  15.         body: RefreshIndicator(
  16.           onRefresh: getMTMavailableamount1,
  17.           child: FutureBuilder&lt;List&lt;dynamic&gt;&gt;(
  18.             future: _futureList,
  19.             builder: (context, snapshot) {
  20.               if (snapshot.hasData) {
  21.                 List&lt;dynamic&gt; positions = snapshot.data ?? [];
  22.                 return ListView.builder(
  23.                   itemCount: positions.length,
  24.                   itemBuilder: (context, index) {
  25.                     String custID = positions[index][0];
  26.                     String custName = positions[index][1];
  27.                     double m2m = double.parse(positions[index][2]);
  28.                     double available = double.parse(positions[index][3]);

答案1

得分: 1

Introduce new variable called uniqueKey and that should be ValueKey with the value of future.

  1. late ValueKey<Future> uniqueKey;
  2. Future<void> getMTMavailableamount1() async {
  3.     final temp = ModelsPositions().getMasterPositions();
  4.     setState(() {
  5.       _futureList = temp;
  6.       uniqueKey = ValueKey(_futureList);
  7.     });
  8.   }
  10. @override
  11.   Widget build(BuildContext context) {
  12.     return Scaffold(
  13.         appBar: AppBar(
  14.           title: const Text('Master Control'),
  15.           centerTitle: true,
  16.         ),
  17.         body: RefreshIndicator(
  18.           onRefresh: getMTMavailableamount1,
  19.           child: FutureBuilder<List<dynamic>>(
  20.             future: _futureList,
  21.             key: uniqueKey,
  22.             builder: (context, snapshot) {
  23.               if (snapshot.hasData) {
  24.                 List<dynamic> positions = snapshot.data ?? [];
  25.                 return ListView.builder(
  26.                   itemCount: positions.length,
  27.                   itemBuilder: (context, index) {
  28.                     String custID = positions[index][0];
  29.                     String custName = positions[index][1];
  30.                     double m2m = double.parse(positions[index][2]);
  31.                     double available = double.parse(positions[index][3]);

Make sure you initiated uniqueKey at initState().

  2.   @override
  3.   void initState() {
  4.     super.initState();
  5.     _futureList = ModelsPositions().getMasterPositions();
  6.      uniqueKey = ValueKey<Future>(_futureList);
  7.   }

Edited

You misused setState. your code creates a new inline function instead of calling setState of State. setState looks like as following.

  1. setState(() {
  2.       _futureList = temp;
  3.       uniqueKey = ValueKey(_futureList);
  4.     });
英文:

Introduce new variable called uniqueKey and that should be ValueKey with the value of future.

  1. late ValueKey&lt;Future&gt; uniqueKey;
  2. Future&lt;void&gt; getMTMavailableamount1() async {
  3.     final temp = ModelsPositions().getMasterPositions();
  4.     setState(() {
  5.       _futureList = temp;
  6.       uniqueKey = ValueKey(_futureList);
  7.     });
  8.   }
  10. @override
  11.   Widget build(BuildContext context) {
  12.     return Scaffold(
  13.         appBar: AppBar(
  14.           title: const Text(&#39;Master Control&#39;),
  15.           centerTitle: true,
  16.         ),
  17.         body: RefreshIndicator(
  18.           onRefresh: getMTMavailableamount1,
  19.           child: FutureBuilder&lt;List&lt;dynamic&gt;&gt;(
  20.             future: _futureList,
  21.             key: uniqueKey,
  22.             builder: (context, snapshot) {
  23.               if (snapshot.hasData) {
  24.                 List&lt;dynamic&gt; positions = snapshot.data ?? [];
  25.                 return ListView.builder(
  26.                   itemCount: positions.length,
  27.                   itemBuilder: (context, index) {
  28.                     String custID = positions[index][0];
  29.                     String custName = positions[index][1];
  30.                     double m2m = double.parse(positions[index][2]);
  31.                     double available = double.parse(positions[index][3]);

Make sure you initiated uniqueKey at initState().

  2.   @override
  3.   void initState() {
  4.     super.initState();
  5.     _futureList = ModelsPositions().getMasterPositions();
  6.      uniqueKey = ValueKey&lt;Future&gt;(_futureList);
  7.   }

Edited

You misused setState. your code creates a new inline function instead of calling setState of State. setState looks like as following.

  1. setState(() {
  2.       _futureList = temp;
  3.       uniqueKey = ValueKey(_futureList);
  4.     });

答案2

得分: 0

  1. import 'dart:async';
  2. import 'package:e2/pages/authorize.dart';
  3. import 'package:flutter/material.dart';
  4. import 'package:fluttertoast/fluttertoast.dart';
  5. import 'package:e2/Models/model_positions.dart';
  6. import 'package:http/http.dart' as http;
  7. import 'dart:convert';
  9. class MasterControl extends StatefulWidget {
  10.   const MasterControl({super.key});
  12.   @override
  13.   State<MasterControl> createState() => _MasterControlState();
  14. }
  16. class _MasterControlState extends State<MasterControl> {
  17.   List<dynamic> _selectedItems = [];
  18.   // List<MasterPositions> positions = [];
  19.   late Future<List<dynamic>> _futureList;
  21.   @override
  22.   void initState() {
  23.     super.initState();
  24.     _futureList = ModelsPositions().getMasterPositions();
  25.     uniqueKey = ValueKey<Future>(_futureList);
  26.   }
  28.   late ValueKey<Future> uniqueKey;
  29.   Future<void> getMTMavailableamount1() async {
  30.     final response = await http.post(
  31.       Uri.parse('https://jhkmmy7zhx2dj2yag74j7p5k2e0fyqnj.lambda-url.ap-south-1.on.aws/'),
  32.       headers: <String, String>{
  33.         'Content-Type': 'application/json; charset=UTF-8',
  34.       },
  35.     );
  36.     final temp = ModelsPositions().getMasterPositions();
  37.     setState() {
  38.       _futureList = temp;
  39.       uniqueKey = ValueKey(_futureList);
  40.     }
  41.   }
  43.   @override
  44.   Widget build(BuildContext context) {
  45.     return Scaffold(
  46.       appBar: AppBar(
  47.         title: const Text('Master Control'),
  48.         centerTitle: true,
  49.       ),
  50.       body: RefreshIndicator(
  51.         onRefresh: getMTMavailableamount1,
  52.         child: FutureBuilder<List<dynamic>>(
  53.           future: _futureList,
  54.           key: uniqueKey,
  55.           builder: (context, snapshot) {
  56.             if (snapshot.hasData) {
  57.               List<dynamic> positions = snapshot.data ?? [];
  58.               return ListView.builder(
  59.                 itemCount: positions.length,
  60.                 itemBuilder: (context, index) {
  61.                   String custID = positions[index][0];
  62.                   String custName = positions[index][1];
  63.                   double m2m = double.parse(positions[index][2]);
  64.                   double available = double.parse(positions[index][3]);
  65.                   // String symbol = positions[index][4];
  67.                   return Card(
  68.                     child: Row(children: [
  69.                       Checkbox(
  70.                         value: _selectedItems.contains(positions[index]),
  71.                         onChanged: (value) {
  72.                           setState(() {
  73.                             if (value == null) {
  74.                               return;
  75.                             }
  76.                             if (value) {
  77.                               _selectedItems.add(positions[index]);
  78.                             } else {
  79.                               _selectedItems.removeWhere((item) => item == positions[index]);
  80.                             }
  81.                           });
  82.                         },
  83.                       ),
  84.                       Flexible(
  85.                         child: Column(
  86.                           crossAxisAlignment: CrossAxisAlignment.stretch,
  87.                           children: [
  88.                             const SizedBox(height: 2),
  89.                             Text(custID),
  90.                             const SizedBox(height: 2),
  91.                             Text(custName),
  92.                             const SizedBox(height: 2),
  93.                           ],
  94.                         ),
  95.                       ),
  96.                       Flexible(
  97.                         // fit: FlexFit.tight,
  98.                         child: Column(
  99.                           mainAxisAlignment: MainAxisAlignment.center,
  100.                           crossAxisAlignment: CrossAxisAlignment.stretch,
  101.                           children: [
  102.                             const SizedBox(height: 3),
  103.                             Text(
  104.                               'MTM       : $m2m',
  105.                               softWrap: false,
  106.                               style: TextStyle(
  107.                                 fontFamily: 'Roboto',
  108.                                 color: m2m > 0.0
  109.                                     ? const Color.fromARGB(255, 11, 180, 16)
  110.                                     : Colors.red[600],
  111.                               ),
  112.                             ),
  113.                             const SizedBox(height: 5),
  114.                             Text(
  115.                               'Available : $available',
  116.                               softWrap: false,
  117.                               style: TextStyle(
  118.                                 fontFamily: 'Roboto',
  119.                                 color: available > 0.0
  120.                                     ? const Color.fromARGB(255, 11, 180, 16)
  121.                                     : Colors.red[600],
  122.                               ),
  123.                             ),
  124.                             const SizedBox(height: 5),
  125.                           ],
  126.                         ),
  127.                       ),
  128.                     ]),
  129.                   );
  130.                 },
  131.               );
  132.             } else if (snapshot.hasError) {
  133.               return const Center(child: Text('Failed to fetch Positions Summary'));
  134.             }
  135.             return const Center(child: CircularProgressIndicator());
  136.           },
  137.         ),
  138.       ),
  139.     );
  140.   }
  141. }
  143. class LambdaResponse {
  144.   late int statusCode;
  145.   late String msg;
  147.   LambdaResponse({required this.statusCode, required this.msg});
  149.   factory LambdaResponse.fromJson(String response) {
  150.     print('here1');
  151.     print(response);
  152.     return LambdaResponse(
  153.       statusCode: 1,
  154.       msg: response,
  155.     );
  156.   }
  157. }

这是您提供的Dart代码的翻译版本。如您所要求，我已经去掉了代码部分的翻译。如果您有任何其他问题或需要进一步的帮助，请随时告诉我。

英文: 
  1. import &#39;dart:async&#39;;
  2. import &#39;package:e2/pages/authorize.dart&#39;;
  3. import &#39;package:flutter/material.dart&#39;;
  4. import &#39;package:fluttertoast/fluttertoast.dart&#39;;
  5. import &#39;package:e2/Models/model_positions.dart&#39;;
  6. import &#39;package:http/http.dart&#39; as http;
  7. import &#39;dart:convert&#39;;
  8. class MasterControl extends StatefulWidget {
  9. const MasterControl({super.key});
  10. @override
  11. State&lt;MasterControl&gt; createState() =&gt; _MasterControlState();
  12. }
  13. class _MasterControlState extends State&lt;MasterControl&gt; {
  14. List&lt;dynamic&gt; _selectedItems = [];
  15. //List&lt;MasterPositions&gt; positions = [];
  16. late Future&lt;List&lt;dynamic&gt;&gt; _futureList;
  17. @override
  18. void initState() {
  19. super.initState();
  20. _futureList = ModelsPositions().getMasterPositions();
  21. uniqueKey = ValueKey&lt;Future&gt;(_futureList);
  22. }
  23. late ValueKey&lt;Future&gt; uniqueKey;
  24. Future&lt;void&gt; getMTMavailableamount1() async {
  25. final response = await http.post(
  26. Uri.parse(
  27. &#39;https://jhkmmy7zhx2dj2yag74j7p5k2e0fyqnj.lambda-url.ap-south-1.on.aws/&#39;),
  28. headers: &lt;String, String&gt;{
  29. &#39;Content-Type&#39;: &#39;application/json; charset=UTF-8&#39;,
  30. },
  31. );
  32. final temp = ModelsPositions().getMasterPositions();
  33. setState() {
  34. _futureList = temp;
  35. uniqueKey = ValueKey(_futureList);
  36. }
  37. }
  38. @override
  39. Widget build(BuildContext context) {
  40. return Scaffold(
  41. appBar: AppBar(
  42. title: const Text(&#39;Master Control&#39;),
  43. centerTitle: true,
  44. ),
  45. body: RefreshIndicator(
  46. onRefresh: getMTMavailableamount1,
  47. child: FutureBuilder&lt;List&lt;dynamic&gt;&gt;(
  48. future: _futureList,
  49. key: uniqueKey,
  50. builder: (context, snapshot) {
  51. if (snapshot.hasData) {
  52. List&lt;dynamic&gt; positions = snapshot.data ?? [];
  53. return ListView.builder(
  54. itemCount: positions.length,
  55. itemBuilder: (context, index) {
  56. String custID = positions[index][0];
  57. String custName = positions[index][1];
  58. double m2m = double.parse(positions[index][2]);
  59. double available = double.parse(positions[index][3]);
  60. //String symbol = positions[index][4];
  61. return Card(
  62. child: Row(children: [
  63. Checkbox(
  64. value: _selectedItems.contains(positions[index]),
  65. onChanged: (value) {
  66. setState(() {
  67. if (value == null) {
  68. return;
  69. }
  70. if (value) {
  71. _selectedItems.add(positions[index]);
  72. } else {
  73. _selectedItems.removeWhere(
  74. (item) =&gt; item == positions[index]);
  75. }
  76. });
  77. },
  78. ),
  79. Flexible(
  80. child: Column(
  81. crossAxisAlignment: CrossAxisAlignment.stretch,
  82. children: [
  83. const SizedBox(height: 2),
  84. Text(custID),
  85. const SizedBox(height: 2),
  86. Text(custName),
  87. const SizedBox(height: 2),
  88. ],
  89. ),
  90. ),
  91. Flexible(
  92. //fit: FlexFit.tight,
  93. child: Column(
  94. mainAxisAlignment: MainAxisAlignment.center,
  95. crossAxisAlignment: CrossAxisAlignment.stretch,
  96. children: [
  97. const SizedBox(height: 3),
  98. Text(
  99. &#39;MTM       : $m2m&#39;,
  100. softWrap: false,
  101. style: TextStyle(
  102. fontFamily: &#39;Roboto&#39;,
  103. color: m2m &gt; 0.0
  104. ? const Color.fromARGB(255, 11, 180, 16)
  105. : Colors.red[600]),
  106. ),
  107. const SizedBox(height: 5),
  108. Text(
  109. &#39;Available : $available&#39;,
  110. softWrap: false,
  111. style: TextStyle(
  112. fontFamily: &#39;Roboto&#39;,
  113. color: available &gt; 0.0
  114. ? const Color.fromARGB(255, 11, 180, 16)
  115. : Colors.red[600]),
  116. ),
  117. const SizedBox(height: 5),
  118. ],
  119. ),
  120. ),
  121. ]));
  122. },
  123. );
  124. } else if (snapshot.hasError) {
  125. return const Center(
  126. child: Text(&#39;Failed to fetch Positions Summary&#39;));
  127. }
  128. return const Center(child: CircularProgressIndicator());
  129. },
  130. ),
  131. ),);
  132. }
  133. }
  134. class LambdaResponse {
  135. late int statusCode;
  136. late String msg;
  137. LambdaResponse({required this.statusCode, required this.msg});
  138. factory LambdaResponse.fromJson(String response) {
  139. print(&#39;here1&#39;);
  140. print(response);
  141. return LambdaResponse(
  142. statusCode: 1,
  143. msg: response,
  144. );
  145. }
  146. }

huangapple
  • 本文由 发表于 2023年3月9日 18:04:49
  • 转载请务必保留本文链接：https://go.coder-hub.com/75683068.html
  • dart
  • flutter
匿名

发表评论

匿名网友

:?: :razz: :sad: :evil: :!: :smile: :oops: :grin: :eek: :shock: :???: :cool: :lol: :mad: :twisted: :roll: :wink: :idea: :arrow: :neutral: :cry: :mrgreen:

确定