Flutter - Keyed Collection in Widgets

These are replacements to BottomNavigationBar, IndexedStack, and TabController that use item keys instead if numeric indexes.

Problem

With traditional widgets, you write something like

const tabFavorites = 0;
const tabSearch = 1;
// ...
if (tabIndex == tabFavorites) {
  // ...
}

If items in your bar can change, you get an error-prone conversion from indexes to meanings. Also with a mature architecture you tend to use enum for your tabs, and even with constant bar items you must write code to convert between enum and int.

Solution

This package provides widgets to be used with any type instead of int. In most cases you will use enum.

Some advantages of enum over indexes:

• No way for the value to fall out of range.
• Easier debugging with IDE tools.
• You will never use magic numbers for indexes.
• No need to synchronize the order of children between different widgets.

String is also a good type to use with these widgets if you have dynamic or potentially unlimited tabs (like in a browser or a document editor) but still want meaningful keys instead of indexes.

KeyedBottomNavigationBar and KeyedStack

This example uses an enum for selectable navigation items:

This example is runnable. Download the repository and open the example project. Then run nav_stack.dart

enum TabEnum { favorites, search }

class _MyScreenState extends State<MyScreen> {
  TabEnum _tab = TabEnum.favorites;

  @override
  Widget build(BuildContext context) {
    // This is a simplified example: IndexedStack and KeyedStack are only
    // meaningful if they contain stateful widgets to preserve state
    // between switches.
    return Scaffold(
      body: KeyedStack<TabEnum>(
        itemKey: _tab,
        children: const {
          TabEnum.favorites: Center(
            key: ValueKey('favorites_pane'),
            child: Text('Favorites'),
          ),
          TabEnum.search: Center(
            key: ValueKey('search_pane'),
            child: Text('Search'),
          ),
        },
      ),
      bottomNavigationBar: KeyedBottomNavigationBar<TabEnum>(
        currentItemKey: _tab,
        items: const {
          TabEnum.favorites: BottomNavigationBarItem(
            icon: Icon(Icons.star),
            label: 'Favorites',
          ),
          TabEnum.search: BottomNavigationBarItem(
            icon: Icon(Icons.search),
            label: 'Search',
          ),
        },
        onTap: (tab) => setState(() {
          _tab = tab;
        }),
      ),
    );
  }
}

KeyedBottomNavigationBar and KeyedStack support all the arguments of their traditional counterparts. The only difference is that current keys are required and do not default to first element.

KeyedTabController, KeyedTabBar, KeyedTabBarView

Minimal Example

This example uses enum for tabs:

This example is runnable. Download the repository and open the example project. Then run tabs.dart

enum MyTab { one, two, three }

class _MyScreenState extends State<MyScreen> with TickerProviderStateMixin {
  late final _tabController = KeyedTabController<TabEnum>(
    initialKey: TabEnum.three,
    keys: [TabEnum.one, TabEnum.two, TabEnum.three],
    vsync: this,
  );

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('${_tabController.currentKey}'),
        bottom: KeyedTabBar(
          tabs: {
            for (final key in _tabController.keys) key: Tab(text: '$key'),
          },
          controller: _tabController,
        ),
      ),
      body: KeyedTabBarView(
        children: {
          for (final key in _tabController.keys)
            key: Center(child: Text('$key content')),
        },
        controller: _tabController,
      ),
    );
  }
}

Redundant Children

The ordinary TabBar and TabBarView must have exactly as many children as their controller is set to. This means that if you need to hide some tabs, there must be three locations in your code to know that:

1. The code that updates the controller.
2. The code that creates TabBar widget with tab headers.
3. The code that creates TabBarView widget with tab contents.

This is extremely error-prone.

With this package, KeyedTabBar and KeyedTabBarView have maps of children, so they can contain more widgets than the controller wants to show.

This means that you can unconditionally pass all children for all possible tabs to them, and the only location in your code that needs to know what tabs to show is the code that updates the controller.

Using KeyedTabController as TabController

KeyedTabController implements TabController and is immediately usable as one. If you ever need to get the tab index or select a tab by index, do it as you normally would.

UnanimatedKeyedTabController

With ordinary TabController, you need TickerProvider to create it. And this limits the usage. You must create TabController in a widget. If you want your BLoC or other business logic code to be aware of tabs or control them, it may be tricky to pass the controller there.

This package provides UnanimatedKeyedTabController which has the logic core for KeyedTabController, but not its animation. You can create this controller anywhere and then add the animation in your widget.

Create it like this:

final unanimatedController = UnanimatedKeyedTabController<TabEnum>(
  keys: [TabEnum.one, TabEnum.two, TabEnum.three],
  initialKey: TabEnum.three,
);

Then create KeyedTabController in your widget:

class _MyScreenState extends State<MyScreen> with TickerProviderStateMixin {
  late final _tabController = KeyedTabController<TabEnum>.fromUnanimated(
    controller: unanimatedController,
    vsync: this,
  );
  // ...

This binds the two controllers. If you change the tab via UnanimatedKeyedTabController, then KeyedTabController gets updated, and the tab change is animated in the UI.

And if the user changes the tab by interacting with it, both controllers get updated.

Mutable Tabs and Animation Duration

Ordinary TabController has a fixed length and animationDuration. If you need to change them, you must create a new controller and replace it everywhere.

KeyedTabController has these mutable.

You can change the tabs at any time by setting KeyedTabController.keys property. If the currently selected tab also exists in the new set, its selection is preserved, otherwise the first new tab gets selected.

This is possible because KeyedTabController does not extend but contains TabController and so it can re-create its internal TabController with different parameters without disturbing its own listeners.

TickerProviderStateMixin vs SingleTickerProviderStateMixin

In Flutter's tab examples, you often see the widget's State created with SingleTickerProviderStateMixin. This only allows one TabController to be created in it. However, KeyedTabController re-creates its TabController if you change keys or animationDuration, so it will break if created with SingleTickerProviderStateMixin.

You should use TickerProviderStateMixin for your widgets instead. It allows many TabController objects to be created with it.

DefaultKeyedTabController

Flutter provides DefaultTabController widget which accepts the number of tabs, creates a TabController and provides it to all tab-related widgets under it.

It has the following advantages:

1. It is declarative. You don't have to manage your TabController and dispose it.
2. It allows to change the number of tabs. You just change the length passed to this widget, and it re-creates the TabController, and all widgets under it are updated for the new number of tabs.

This is matched by DefaultKeyedTabController. Although tabs get mutable with this package, the advantage #1 still stands.

This widget comes in two forms:

fromKeys

DefaultKeyedTabController.fromKeys(
  keys: [TabEnum.one, TabEnum.two],
  child: ...
),

Use this when you know the keys to show in your widget.

fromUnanimated

DefaultKeyedTabController.fromUnanimated(
  controller: unanimatedController,
  child: ...
),

Use this if you use UnanimatedKeyedTabController.

Creating Widgets for DefaultKeyedTabController

In Flutter, both TabBar and TabBarView widgets can be created without the controller argument. In this case, they rely on DefaultTabController widget present in the tree above them and break if it is missing.

This is error-prone because the controller argument may simply be forgotten, and this cannot be detected at compile time.

In this package, the controller argument to KeyedTabBar and KeyedTabBarView is required. To rely on the DefaultKeyedTabController, use .withDefaultController static methods of those widgets instead of their default constructors.

There is still no check at compile time that the default controller is present in the tree, but at least you must explicitly declare that you want it and not just have forgotten to pass the controller.

When to use DefaultKeyedTabController

All things equal, prefer DefaultKeyedTabController over manual KeyedTabController creation. This is because that widget will dispose the controller for you when it is not needed anymore.

Advanced Example

This example shows:

• Changing the set of tabs without re-creating a controller.
• Programmatically activating a tab by its key.
• Programmatically activating a tab by its index.
• Changing the animation duration without re-creating a controller.
• DefaultKeyedTabController widgets.
• UnanimatedKeyedTabController.
• Replacing the UnanimatedKeyedTabController that a KeyedTabController is linked to.

This example is runnable. Download the repository and open the example project. Then run nav_stack_tabs.dart

enum_map

Although enum enhances type safety for tabs, it is still not absolute. In widgets, you may still forget to use all keys in children map and only know that at runtime.

You can make this compile-time safe by using enum_map package that generates maps that are guaranteed to have all keys at compile time (see that package's README for more info):

@unmodifiableEnumMap                                    // CHANGED
enum TabEnum { one, two, three }

class _MyScreenState extends State<MyScreen> with TickerProviderStateMixin {
  late final _tabController = KeyedTabController<TabEnum>(
    initialKey: TabEnum.three,
    keys: [TabEnum.one, TabEnum.two, TabEnum.three],
    vsync: this,
  );

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('${_tabController.currentKey}'),
        bottom: KeyedTabBar(
          controller: _tabController,
          tabs: const UnmodifiableTabEnumMap(           // CHANGED
            one: Tab(text: 'One'),                      // CHANGED
            two: Tab(text: 'Two'),                      // CHANGED
            three: Tab(text: 'Three'),                  // CHANGED
          ),                                            // CHANGED
        ),
      ),
      body: KeyedTabBarView(
        controller: _tabController,
        children: const UnmodifiableTabEnumMap(         // CHANGED
          one: Center(child: Text('One content')),      // CHANGED
          two: Center(child: Text('Two content')),      // CHANGED
          three: Center(child: Text('Three content')),  // CHANGED
        ),                                              // CHANGED
      ),
    );
  }
}

Support Chat

Do you have any questions? Feel free to ask in the Telegram Support Chat.

Or even just join to say 'Hi!'. I like to hear from the users.

Use this package as a library

Depend on it

Run this command:

With Flutter:

 $ flutter pub add keyed_collection_widgets

This will add a line like this to your package's pubspec.yaml (and run an implicit flutter pub get):

dependencies:
  keyed_collection_widgets: ^0.4.1

Alternatively, your editor might support flutter pub get. Check the docs for your editor to learn more.

Import it

Now in your Dart code, you can use:

import 'package:keyed_collection_widgets/keyed_collection_widgets.dart'; 

example/README.md

example

All examples here are runnable. Download this repository to your computer and open it in your editor. In Android Studio, you can run examples like this:

1. nav_stack.dart

This example shows KeyedBottomNavigationBar and KeyedStack widgets:

2. tabs.dart

This example shows KeyedTabController and widgets KeyedTabBar and KeyedTabBarView:

3. tabs_enum_map.dart

This is a variation of tabs.dart that uses enum_map for compile-time type safety with tabs.

4. unanimated_keyed_tab_controller.dart

This is a variation of tabs.dart that uses `UnanimatedKeyedTabController.

5. nav_stack_tabs.dart

This is the ultimate advanced example that shows:

• Changing the set of tabs without re-creating a controller.
• Programmatically activating a tab by its key.
• Programmatically activating a tab by its index.
• Changing the animation duration without re-creating a controller.
• DefaultKeyedTabController widgets.
• UnanimatedKeyedTabController.
• Replacing UnanimatedKeyedTabController that KeyedTabController is linked to.

Download Details:

Author: alexeyinkin

Source Code: https://github.com/alexeyinkin/flutter-keyed-collection-widgets

#widget #key 

What is GEEK

Buddha Community

Google's Flutter 1.20 stable announced with new features - Navoki

Flutter Google cross-platform UI framework has released a new version 1.20 stable.

Flutter is Google’s UI framework to make apps for Android, iOS, Web, Windows, Mac, Linux, and Fuchsia OS. Since the last 2 years, the flutter Framework has already achieved popularity among mobile developers to develop Android and iOS apps. In the last few releases, Flutter also added the support of making web applications and desktop applications.

Last month they introduced the support of the Linux desktop app that can be distributed through Canonical Snap Store(Snapcraft), this enables the developers to publish there Linux desktop app for their users and publish on Snap Store.  If you want to learn how to Publish Flutter Desktop app in Snap Store that here is the tutorial.

Flutter 1.20 Framework is built on Google’s made Dart programming language that is a cross-platform language providing native performance, new UI widgets, and other more features for the developer usage.

Here are the few key points of this release:

Performance improvements for Flutter and Dart

In this release, they have got multiple performance improvements in the Dart language itself. A new improvement is to reduce the app size in the release versions of the app. Another performance improvement is to reduce junk in the display of app animation by using the warm-up phase.

If your app is junk information during the first run then the Skia Shading Language shader provides for pre-compilation as part of your app’s build. This can speed it up by more than 2x.

Added a better support of mouse cursors for web and desktop flutter app,. Now many widgets will show cursor on top of them or you can specify the type of supported cursor you want.

Autofill for mobile text fields

Autofill was already supported in native applications now its been added to the Flutter SDK. Now prefilled information stored by your OS can be used for autofill in the application. This feature will be available soon on the flutter web.

A new widget for interaction

InteractiveViewer is a new widget design for common interactions in your app like pan, zoom drag and drop for resizing the widget. Informations on this you can check more on this API documentation where you can try this widget on the DartPad. In this release, drag-drop has more features added like you can know precisely where the drop happened and get the position.

Updated Material Slider, RangeSlider, TimePicker, and DatePicker

In this new release, there are many pre-existing widgets that were updated to match the latest material guidelines, these updates include better interaction with Slider and RangeSlider, DatePicker with support for date range and time picker with the new style.

New pubspec.yaml format

Other than these widget updates there is some update within the project also like in pubspec.yaml file format. If you are a flutter plugin publisher then your old pubspec.yaml  is no longer supported to publish a plugin as the older format does not specify for which platform plugin you are making. All existing plugin will continue to work with flutter apps but you should make a plugin update as soon as possible.

Preview of embedded Dart DevTools in Visual Studio Code

Visual Studio code flutter extension got an update in this release. You get a preview of new features where you can analyze that Dev tools in your coding workspace. Enable this feature in your vs code by _dart.previewEmbeddedDevTools_setting. Dart DevTools menu you can choose your favorite page embed on your code workspace.

Network tracking

The updated the Dev tools comes with the network page that enables network profiling. You can track the timings and other information like status and content type of your** network calls** within your app. You can also monitor gRPC traffic.

Generate type-safe platform channels for platform interop

Pigeon is a command-line tool that will generate types of safe platform channels without adding additional dependencies. With this instead of manually matching method strings on platform channel and serializing arguments, you can invoke native class and pass nonprimitive data objects by directly calling the Dartmethod.

There is still a long list of updates in the new version of Flutter 1.2 that we cannot cover in this blog. You can get more details you can visit the official site to know more. Also, you can subscribe to the Navoki newsletter to get updates on these features and upcoming new updates and lessons. In upcoming new versions, we might see more new features and improvements.

You can get more free Flutter tutorials you can follow these courses:

• Setup Flutter Desktop on Windows, Linux, MacOS using VSCode and Build – Flutter Tutorial
• Flutter Desktop Linux app | Build and Publish on Snapcraft Store
• Firebase Local Emulator Suite in Flutter

#dart #developers #flutter #app developed #dart devtools in visual studio code #firebase local emulator suite in flutter #flutter autofill #flutter date picker #flutter desktop linux app build and publish on snapcraft store #flutter pigeon #flutter range slider #flutter slider #flutter time picker #flutter tutorial #flutter widget #google flutter #linux #navoki #pubspec format #setup flutter desktop on windows

What is Flutter and why you should learn it?

Flutter is an open-source UI toolkit for mobile developers, so they can use it to build native-looking** Android and iOS** applications from the same code base for both platforms. Flutter is also working to make Flutter apps for Web, PWA (progressive Web-App) and Desktop platform (Windows,macOS,Linux).

Flutter was officially released in December 2018. Since then, it has gone a much stronger flutter community.

There has been much increase in flutter developers, flutter packages, youtube tutorials, blogs, flutter examples apps, official and private events, and more. Flutter is now on top software repos based and trending on GitHub.

Flutter meaning?

What is Flutter? this question comes to many new developer’s mind.

Flutter means flying wings quickly, and lightly but obviously, this doesn’t apply in our SDK.

So Flutter was one of the companies that were acquired by **Google **for around $40 million. That company was based on providing gesture detection and recognition from a standard webcam. But later when the Flutter was going to release in alpha version for developer it’s name was Sky, but since Google already owned Flutter name, so they rename it to Flutter.

Where Flutter is used?

Flutter is used in many startup companies nowadays, and even some MNCs are also adopting Flutter as a mobile development framework. Many top famous companies are using their apps in Flutter. Some of them here are

Dream11

NuBank

Reflectly app

Abbey Road Studios

and many more other apps. Mobile development companies also adopted Flutter as a service for their clients. Even I was one of them who developed flutter apps as a freelancer and later as an IT company for mobile apps.

#dart #flutter #uncategorized #flutter framework #flutter jobs #flutter language #flutter meaning #flutter meaning in hindi #google flutter #how does flutter work #what is flutter

The Ultimate Guide To Tik Tok Clone App With Firebase - Ep 2

The Ultimate Guide To Tik Tok Clone App With Firebase - Ep 2
In this video, I'm going to show you how to make a Cool Tik Tok App a new Instagram using Flutter,firebase and visual studio code.

In this tutorial, you will learn how to Upload a Profile Pic to Firestore Data Storage.

🚀 Nice, clean and modern TikTok Clone #App #UI made in #Flutter⚠️

Starter Project : https://github.com/Punithraaj/Flutter_Tik_Tok_Clone_App/tree/Episode1

► Timestamps 
0:00 Intro 0:20 
Upload Profile Screen 
16:35 Image Picker
20:06 Image Cropper 
24:25 Firestore Data Storage Configuration.

⚠️ IMPORTANT: If you want to learn, I strongly advise you to watch the video at a slow speed and try to follow the code and understand what is done, without having to copy the code, and then download it from GitHub.

► Social Media 
GitHub: https://github.com/Punithraaj/Flutter_Tik_Tok_Clone_App.git
LinkedIn: https://www.linkedin.com/in/roaring-r...
Twitter: https://twitter.com/roaringraaj
Facebook: https://www.facebook.com/flutterdartacademy

► Previous Episode : https://youtu.be/QnL3fr-XpC4
► Playlist: https://youtube.com/playlist?list=PL6vcAuTKAaYe_9KQRsxTsFFSx78g1OluK

I hope you liked it, and don't forget to like,comment, subscribe, share this video with your friends, and star the repository on GitHub!
⭐️ Thanks for watching the video and for more updates don't forget to click on the notification. 
⭐️Please comment your suggestion for my improvement. 
⭐️Remember to like, subscribe, share this video, and star the repo on Github :)

Hope you enjoyed this video!
If you loved it, you can Buy me a coffee : https://www.buymeacoffee.com/roaringraaj

LIKE & SHARE & ACTIVATE THE BELL Thanks For Watching :-)
 
https://youtu.be/F_GgZVD4sDk

#flutter tutorial - tiktok clone with firebase #flutter challenge @tiktokclone #fluttertutorial firebase #flutter firebase #flutter pageview #morioh #flutter

Flutter Hotel Booking UI - Book your Stay At A New Hotel With Flutter - Ep1

https://youtu.be/-tHUmjIkGJ4
Flutter Hotel Booking UI - Book your Stay At A New Hotel With Flutter - Ep1
#flutter #fluttertravelapp #hotelbookingui #flutter ui design 

In this video, I'm going to show you how to make a Cool Hotel Booking App using Flutter and visual studio code. 

In this tutorial, you will learn how to create a Splash Screen and Introduction Screen, how to implement a SmoothPageIndicator in Flutter. 

🚀 Nice, clean and modern Hotel Booking #App #UI made in #Flutter 

⚠️ IMPORTANT: If you want to learn, I strongly advise you to watch the video at a slow speed and try to follow the code and understand what is done, without having to copy the code, and then download it from GitHub. 

► Social Media 

    GitHub: https://github.com/Punithraaj 

    LinkedIn: https://www.linkedin.com/in/roaring-r...

    Twitter: https://twitter.com/roaringraaj

    Facebook: https://www.facebook.com/flutterdartacademy

I hope you liked it, and don't forget to like,comment, subscribe, share this video with your friends, and star the repository on GitHub! 

⭐️ Thanks for watching the video and for more updates don't forget to click on the notification.⭐️Please comment your suggestion for my improvement. ⭐️Remember to like, subscribe, share this video, and star the repo on Github :)Hope you enjoyed this video! If you loved it, you can Buy me a coffee : https://www.buymeacoffee.com/roaringraaj

#flutter riverpod #flutter travel app #appointment app flutter #morioh

Adobe XD plugin for Flutter with CodePen Tutorial

Recently Adobe XD releases a new version of the plugin that you can use to export designs directly into flutter widgets or screens. Yes, you read it right, now you can make and export your favorite design in Adobe XD and export all the design in the widget form or as a full-screen design, this can save you a lot of time required in designing.

What we will do?
I will make a simple design of a dialogue box with a card design with text over it as shown below. After you complete this exercise you can experiment with the UI. You can make your own components or import UI kits available with the Adobe XD.

#developers #flutter #adobe xd design export to flutter #adobe xd flutter code #adobe xd flutter code generator - plugin #adobe xd flutter plugin #adobe xd flutter plugin tutorial #adobe xd plugins #adobe xd to flutter #adobe xd tutorial #codepen for flutter.