dart

Flutter之路由管理(页面跳转)

由 放肆的年华 提交于 2020-12-14 13:27:37
路由:核心是 路由映射表 . 如：名字 detail 映射到 DetailPage 页面等 在Flutter中，路由管理主要有两个类：Route和Navigator. Route 一个页面要想被路由统一管理，必须包装为一个Route Navigator 管理所有的Route的Widget，通过一个Stack来进行管理. MaterialApp、CupertinoApp、WidgetsApp它们默认是有插入Navigator的,在需要的时候，只需要直接使用即可. Navigator.of(context) Navigator常用方法: // 路由跳转：传入一个路由对象 Future<T> push<T extendsObject>(Route<T> route) // 路由跳转：传入一个名称（命名路由） Future<T> pushNamed<T extendsObject>( String routeName, { Object arguments, }) // 路由返回：可以传入一个参数 bool pop<T extendsObject>([ T result ]) 命名路由 命名路由是将名字和路由的映射关系，在一个地方进行统一的管理 有了命名路由，就可以通过 Navigator.pushNamed() 方法来跳转到新的页面 命名路由的位置 放在MaterialApp的

Unhandled Exception: MissingPluginException(No implementation found for method check on channel plugins.flutter.io/connectivity)

由 守給你的承諾、 提交于 2020-12-13 17:55:00
问题 I already added connectivity plugin on my pubspec.yaml . connectivity: ^0.4.6 But still getting this error: E/flutter ( 4789): [ERROR:flutter/lib/ui/ui_dart_state.cc(148)] Unhandled Exception: MissingPluginException(No implementation found for method check on channel plugins.flutter.io/connectivity) E/flutter ( 4789): #0 MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:314:7) E/flutter ( 4789): E/flutter ( 4789): #1 Connectivity.checkConnectivity (package

Unhandled Exception: MissingPluginException(No implementation found for method check on channel plugins.flutter.io/connectivity)

由 北慕城南 提交于 2020-12-13 17:53:44
问题 I already added connectivity plugin on my pubspec.yaml . connectivity: ^0.4.6 But still getting this error: E/flutter ( 4789): [ERROR:flutter/lib/ui/ui_dart_state.cc(148)] Unhandled Exception: MissingPluginException(No implementation found for method check on channel plugins.flutter.io/connectivity) E/flutter ( 4789): #0 MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:314:7) E/flutter ( 4789): E/flutter ( 4789): #1 Connectivity.checkConnectivity (package

How to pass access token value in flutter

由 安稳与你 提交于 2020-12-13 07:34:18
问题 I have this codes to get access token which should pass from signin screen -> navscreen -> homescreen-> griddashboard->forms ->add new post and send the post request to server with the token Here is how I get the token Future<dynamic> handleGetTokenSilently() async { String authority = "https://login.microsoftonline.com/$TENANT_ID"; final result = await msal.acquireTokenSilent([SCOPE], authority); if(result !=null){ print('access token (truncated): ${result.accessToken}'); return result; /

How to pass access token value in flutter

由 邮差的信 提交于 2020-12-13 07:33:29
问题 I have this codes to get access token which should pass from signin screen -> navscreen -> homescreen-> griddashboard->forms ->add new post and send the post request to server with the token Here is how I get the token Future<dynamic> handleGetTokenSilently() async { String authority = "https://login.microsoftonline.com/$TENANT_ID"; final result = await msal.acquireTokenSilent([SCOPE], authority); if(result !=null){ print('access token (truncated): ${result.accessToken}'); return result; /

Dart PetitParser to get at AST datastructure created with ExpressionBuilder

由 孤街浪徒 提交于 2020-12-13 04:52:28
问题 I'm new to petitparser, but it looks like it's the sonic screwdriver of parsers. For my first project, I'm building code to parse a simple expression that builds an AST tree of my Node objects, then walks that tree with a few rules to minimize the unneeded parens. I don't know what to pass to the output of .parse() (seems to be a Result) to get access to the tree I defined, so I can call .visit() on the top of the AST. Any ideas? class RIPParser { Parser _make_parser() { final builder =

Dart PetitParser to get at AST datastructure created with ExpressionBuilder

由 我的梦境 提交于 2020-12-13 04:51:28
问题 I'm new to petitparser, but it looks like it's the sonic screwdriver of parsers. For my first project, I'm building code to parse a simple expression that builds an AST tree of my Node objects, then walks that tree with a few rules to minimize the unneeded parens. I don't know what to pass to the output of .parse() (seems to be a Result) to get access to the tree I defined, so I can call .visit() on the top of the AST. Any ideas? class RIPParser { Parser _make_parser() { final builder =

Error “The method [] was called on null” in Flutter while parsing Json

由 ↘锁芯ラ 提交于 2020-12-13 04:50:32
问题 I was creating a Flutter application which parses a simple JSON, and it works well but gives an error in Debug Console in VS Code, My simple JSON file: With Lightest Code snippet : import 'package:flutter/material.dart'; import 'dart:convert'; void main() => runApp(new MyApp()); class MyApp extends StatelessWidget { @override Widget build(BuildContext context) { return new MaterialApp(title: "J2", home: new Homepage()); } } class Homepage extends StatefulWidget { @override State createState()

Error “The method [] was called on null” in Flutter while parsing Json

由 社会主义新天地 提交于 2020-12-13 04:50:08
问题 I was creating a Flutter application which parses a simple JSON, and it works well but gives an error in Debug Console in VS Code, My simple JSON file: With Lightest Code snippet : import 'package:flutter/material.dart'; import 'dart:convert'; void main() => runApp(new MyApp()); class MyApp extends StatelessWidget { @override Widget build(BuildContext context) { return new MaterialApp(title: "J2", home: new Homepage()); } } class Homepage extends StatefulWidget { @override State createState()

How to set, get and update data to the cloud firestore in flutter?

由 徘徊边缘 提交于 2020-12-13 03:46:45
问题 I tried some code but getting an exception. The Exception that I'm getting: java.lang.IllegalArgumentException: Invalid document reference. Document references must have an even number of segments, but Users has 1 I searched for it, according to this, Document references must have an even number of segments like: Collection - document - Collection - document - Collection - document Query for getting data from firestore: String getIsNewUSer; Firestore.instance.collection('Users').document(uid)
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