小编Jak*_*ake的帖子

我正在尝试创建一个系统，我可以在其中验证字符串以检查它是否是 url。( https://www.google.com/ )

我找到了 flutter 包验证器，但这与 dart 2 不兼容，因此与我的代码不兼容。

同样命名，我也找到了验证器包，但我似乎无法让它与我的代码一起正常工作，因为它会引发以下错误；（希望你喜欢我的项目名称；）

Because every version of flutter_test from sdk depends on test 1.3.0 
and every version of validators depends on test ^1.3.3, flutter_test from sdk is incompatible with validators.
So, because gucci depends on both validators ^1.0.0+1 and flutter_test any from sdk, version solving failed.
Unable to reload your application because "flutter packages get" failed to update package dependencies.
Exception: pub get failed (1)

如果您可以找到一个修复程序，validators以便它不会抛出此错误并因此与我的代码一起正常工作，或者建议另一种验证字符串是否符合 …

我正在尝试listView.builder在另一个垂直顶部添加一个水平线listView.builder.两者都listViews应该text在两者之上.

这是我到目前为止所做的,只 listView.builder 绘制了顶部水平,当我尝试单击应该绘制底部垂直的listView.builder位置时,应用程序在调试中崩溃并且我得到错误:NoSuchMethodError: The getter 'visible' was called on null.

另外,我不知道如何添加这两个text字段,所以我把它们遗漏了.

我有很多代码,如果您需要查看更多代码,请在此处执行此操作

Widget _cryptoWidget() {
return new Container(
    child: new Column(
      children: <Widget>[
        new Flexible(
          child: new ListView.builder(
              scrollDirection: Axis.horizontal,
              itemBuilder: (BuildContext context, int index) {
              return _listViewFiller();
            }
          ),
        ),
        new Flexible(
          child: new RefreshIndicator(
          key: refreshKey,
          child: new ListView.builder(
            scrollDirection: Axis.horizontal,
            itemCount: _currencies.length,
            itemBuilder: (BuildContext context, …

我正在编写一个应用程序，该应用程序通过一个水平方向listView和一个垂直方向在同一视图中显示两个媒体流listView。我目前正在listView使用一些漂亮的样板实现信息的底层，可以在这里找到。

我是新手，相信我的代码有些混乱，总之，我收到了错误；

flutter: The following NoSuchMethodError was thrown building Builder:
flutter: The method 'loadCurrencies' was called on null.
flutter: Receiver: null
flutter: Tried calling: loadCurrencies()

试图执行代码时，发现这里在home_page_view.dart到上述样板。

这是我用来激发错误的代码；

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:to_be_deleted/data/crypto_data.dart';
import 'package:to_be_deleted/modules/crypto_presenter.dart';
import 'dart:async';
import 'dart:io';
import 'background.dart';

void main() => runApp(new MyApp());

class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return new MaterialApp(
  title: 'Flutter Demo',
  theme: new ThemeData(
    primarySwatch: Colors.blue,
  ), …

我已经在我创建的应用程序中实现了一种获取用户经纬度坐标的可靠方法，但似乎无法将这些坐标转换为地标。

我还想弄清楚我需要用什么来打印这些数据。

这就是我试图获取这些数据的原因：

List<Placemark> place = [];

void _getPlace() async {
  List<Placemark> newPlace = await _geolocator.placemarkFromCoordinates(_position.latitude, _position.longitude);
  print(newPlace);
  setState(() {
    place = newPlace;
  });
}

谢谢

编辑：

在 CopsOnRoad 的回应之后，我收到此错误：

[VERBOSE-2:ui_dart_state.cc(148)] Unhandled Exception: 

NoSuchMethodError: The method 'placemarkFromCoordinates' was called on null.
Receiver: null
Tried calling: placemarkFromCoordinates(51.4998, -0.129)
#0      Object.noSuchMethod  (dart:core-patch/object_patch.dart:50:5)
#1      _NearbyPageState._getPlace 
package:tr/pages/nearby.dart:128
<asynchronous suspension>
#2      _NearbyPageState._controlCard.<anonymous closure> 
package:tr/pages/nearby.dart:629
#3      GestureRecognizer.invokeCallback 
package:flutter/…/gestures/recognizer.dart:182
#4      TapGestureRecognizer._checkUp 
package:flutter/…/gestures/tap.dart:365
#5      TapGestureRecognizer.acceptGesture 
package:flutter/…/gestures/tap.dart:312
#6      GestureArenaManager.sweep 
package:flutter/…/gestures/arena.dart:156
#7      _WidgetsFlutterBinding&BindingBase&GestureBinding.handleEvent 
package:flutter/…/gestures/binding.dart:222
#8      _WidgetsFlutterBinding&BindingBase&GestureBinding.dispatchEvent (p<…>

Flutter初学者在这里；我收到此错误：type 'Future<dynamic>' is not a subtype of type 'String'

从 Firebase 存储中获取下载 url 的函数

_getImageUrl(var fileName) async {
  print(fileName);
  final StorageReference ref = FirebaseStorage.instance.ref().child('categories/' + fileName);
  Uri downloadUrl = await ref.getDownloadURL();
  var url = downloadUrl.toString();
  return url;
}

我调用函数的地方

child:  Image(
  image:  AdvancedNetworkImage(
    _getImageUrl(menuItem['image'].toString()),
    timeoutDuration: Duration(minutes: 1),
    useDiskCache: true,
    cacheRule: CacheRule(maxAge: const Duration(days: 7)),
  ),
  height: mediaQuery.size.width * 0.22,
  width: mediaQuery.size.width * 0.22,
),

我正在寻找一种将分钟转换为小时和分钟的方法。我正在使用这个intl包，DateFormat但这需要两者hours，minutes所以它不会。

如果我有100分钟，我希望将其转换为01:40. 谢谢

最近，当我尝试调试时，我的代码意外停止编译。我正在运行 Flutter v0.5.1

我能想到的唯一原因是在我将我的 Flutter SDK 从我的桌面移动到一个单独的文件夹之后发生了这种情况。

这是我收到的错误：

Error reading dependency file C:\Users\Jake\Desktop\Other\Flutter\myproject\build\app\intermediates\flutter\debug\snapshot_blob.bin.d: java.lang.ArrayIndexOutOfBoundsException: 1
Error reading dependency file C:\Users\Jake\Desktop\Other\Flutter\myproject\build\app\intermediates\flutter\debug\snapshot_blob.bin.d: java.lang.ArrayIndexOutOfBoundsException: 1
Error reading dependency file C:\Users\Jake\Desktop\Other\Flutter\myproject\build\app\intermediates\flutter\debug\snapshot_blob.bin.d: java.lang.ArrayIndexOutOfBoundsException: 1
Oops; flutter has exited unexpectedly.
Crash report written to C:\Users\Jake\Desktop\Other\Flutter\myproject\flutter_14.log;
please let us know at https://github.com/flutter/flutter/issues.
FAILURE: Build failed with an exception.
* Where:
Script 'C:\Users\Jake\Desktop\flutter_windows_v0.5.1-beta\flutter\packages\flutter_tools\gradle\flutter.gradle' line: 435
* What went wrong:
Execution failed for task ':app:flutterBuildDebug'.
> Process 'command 'C:\Users\Jake\Desktop\flutter_windows_v0.5.1-beta\flutter\bin\flutter.bat'' finished with non-zero exit value 1
* Try:
Run with …

我最近尝试将代码从main.dart一开始迁移home_page.dart到我的应用程序中。由于这样做，我的应用程序现在无法编译，我怀疑是因为它不知道从哪里启动应用程序。

这是我收到的错误Set the 'program' value in your launch config (eg 'bin/main.dart') then launch again （在 VSCode 中）但由于迁移了我没有的代码main.dart，下面是删除前最后使用的版本，包括当前版本home_page.dart

另外，下面是结果 $ flutter doctor -v

main.dart;

import 'dart:async';
import 'dart:convert';
import 'package:flutter/foundation.dart';
import 'package:cryptick_nice_ui/dependency_injection.dart';
import 'package:http/http.dart' as http;
import 'package:flutter/material.dart';
import 'package:cryptick_nice_ui/home_page.dart';

void main() async {
  Injector.configure(Flavor.PROD);
  runApp(new MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      theme: new ThemeData(
          primarySwatch: Colors.pink,
          primaryColor: defaultTargetPlatform == TargetPlatform.iOS
              ? …

我正在寻找有关我的测试应用程序的帮助,以提供一个新闻源,从网站解析它的数据,即VMoneyNews (我有权使用他们的数据).

我的目标是为这个来解析article title,main article text并article image在每一篇文章的Bitcoin News类别执行到listView,在这种情况下的水平listViewRow.

请不要在每篇文章的顶部以粗体显示标题文本,也不要在类似文章的链接中包含.

有人可以请我提供此代码吗？我假设这将使用HTML依赖,但我不知道从哪里开始实现此功能.

谢谢.

我一直在此地址关注教程，但flutter doctor完成并成功运行后似乎仍然无法运行echo $PATH

我能想到的唯一原因是因为我可能最初需要将目录更改为flutter文件夹，而不是用户文件夹，但我怀疑这是否会带来真正的变化。

我已经联系了本教程的作者，他说另一个用户觉得这很有帮助。

I managed to solve it myself after I began looking into 'fish'. Apparently I had to declare the path in "~/.config/fish/config.fish" rather than "~/.bash_profile" and then of course run "source ~/.config/fish/config.fish" rather than "source ~/.bash_profile"

这是我的终端机的外观；

MacBook-Air:~ jake$ cd /users/jake/
MacBook-Air:jake jake$ touch .bash_profile
MacBook-Air:jake jake$ source $HOME/.bash_profile
MacBook-Air:jake jake$ echo $PATH
/flutter/bin:/flutter/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/Users/jake/.composer/vendor/bin:/Users      /jake/.composer/vendor/bin
MacBook-Air:jake jake$ flutter doctor
-bash: flutter: command not found

我期待这样的事情；

非常感谢，杰克