Flutter Widgets (TabBar & TabBarView) The Whole Picture

Hello readers, a couple of weeks back one of the readers commented on my story asking me to write about TabBar and TabBarView widgets. So here it is, we will be talking about these two widgets and also we will be discussing the DefaultTabBarController and TabController as well.

If you are coming from Android Development you might agree with me on this that creating Tabbed layout in Android is not as easy as it is in Flutter. I am an Android Developer as well, and around 7 months back I started with Flutter development, well I struggled a bit at the start but when you compare it to Android development it is very easy to learn and I was actually zapped by the customizations you can do in Flutter. We will go through it all and a lot more in this story on TabBar and TabBarView.

Look at the image below to get an overview of what TabBar looks like.

Image for post

TabBar Layout Overview

Now let us look at the constructor of TabBar first, which is pretty long, but I will bifurcate it into 3 parts so that it is easier to understand.

TabBar(           
  indicatorColor: Colors.white,
  indicatorWeight: 2.0,
  indicatorPadding: EdgeInsets.zero,
  indicatorSize: TabBarIndicatorSize.label,
  indicator: BoxDecoration(),
  ------------------------------------------------
  labelColor: Colors.white,
  labelStyle: TextStyle(),
  labelPadding: EdgeInsets.only(top: 10.0),
  unselectedLabelColor: Colors.grey,
  unselectedLabelStyle: TextStyle(),
  ------------------------------------------------
  isScrollable: false,
  controller: _tabController,  // only  if DefaultTabContoller is not used.
  dragStartBehavior: DragStartBehavior.start,
  mouseCursor: SystemMouseCursors.noDrop,
  physics: ScrollPhysics(parent: AlwaysScrollableScrollPhysics()),
  onTap: (){},
  tabs: [Tab(),]                 // @required list of Tabs

If you look closely at the constructor above I have grouped it into three parts, there are five properties pertaining to the indicator and another five related to label, and the last 7 properties are applicable to the behaviour of the TabBar.

Step 1:

Now to build the TabBar layout in your application the first thing you will need is the Controller. There are two ways to do it either you can use the DefaultTabController or you can build your own TabController.

tip: if you are using a stateless widget then using the DefaultTabController is the best approach. If you are using a stateful widget then you should be building your own TabController.

The DefaultTabController has 3 parameters and you need to wrap your Scaffold inside the DefaultTabController.

return DefaultTabController(
  initialIndex: 1,     // default is 0
  length: 3,           // Number of Tabs
  child: Scaffold()    // Main Layout
);

Step 2:

The next step is the TabBar itself which I discussed earlier, customize your TabBar the way that best suits you according to the parameters mentioned above in the constructor. In the above TabBar constructor, I have mentioned what value each takes in or what widget needs to be used along with that property. Additionally, the onTap() function can be used if you want to alert users by showing a dialogBox or a snackBar or route to another page.

Step 3:

As a required property of TabBar is a list of Tabs, it basically means how many pages are you create accordingly you need to add the Tabs and customize the Icon and Label of the Tabs with the constructor given below and refer to the image of TabBar layout overview.

Tab(
  text: 'Radio',                  // label of the Tab
  icon: Icon(                     // Icon above the label
    Icons.radio,
    color: Colors.white,
  ),
  iconMargin: EdgeInsets.only(bottom: 10.0),  // default margin
  child:
),

tip: there are three main parameters of the Tab widget, the text, icon and iconMargin. If you would like to further customize your Tab then you can use the child property, for example, add an image instead of text and icon. The child property can only be used if you haven’t mentioned text and icon, otherwise, your app will throw an error.

Image for post

Tab(                
  child: Image.asset('images/android.png'),
),
Tab(
  text: 'Radio',
  icon: Icon(
    Icons.radio,
    color: Colors.white,
  ),
  iconMargin: EdgeInsets.only(bottom: 10.0),
),
Tab(
  text: 'Gift',
  icon: Icon(
    Icons.card_giftcard,
    color: Colors.white,
  ),
  iconMargin: EdgeInsets.only(bottom: 10.0),
),

Step 4:

The next step is the TabBarView, this is where you will be creating the layout for each Tab, this where you will be adding all your other widgets, basically setting up your page that you want to display when each Tab is selected. The important thing to remember here is that you need to be careful about the index. The children in the TabBarView should be added according to the Tabs created. For example, if you look at the image above, the Tab says Radio and it is at index 1, then the child at index 1 inside the TabBarView should be about Radio as well, otherwise, your Tab will be mention something and the page that is being displayed will be different. Let me explain with some code…

--------------------------- Constructor ------------------------
TabBarView({
  children: [],
  controller: _tabController,  // only if DefaultTabController is not used
  physics: ScrollPhysics(parent: AlwaysScrollableScrollPhysics()),
  dragStartBehavior: DragStartBehavior.start,    // default
})-------------------- Related to above Tab Code ------------------
 TabBarView(
  children: [
    Center(
        child: Text(
      'This is Android Image Tab',              /// Index:0
      style: TextStyle(fontSize: 32),
    )),
    Center(
        child: Text(
      'This is Radio Tab',                     /// Index:1
      style: TextStyle(fontSize: 32),
    )),
    Center(
        child: Text(
      'This is Gift Tab',                      /// Index:2
      style: TextStyle(fontSize: 32),
    )),
  ],
),

Compare closely the code between the Tab and children of TabBarView, index of every child widget in TabBarView is in accordance with the index of the Tab.

Until now all the above code was written using the DefaultTabController. Now if you want to create your own Controller then, first you need is a stateful widget and TabController object which will be then initialized inside the controller property of TabBar and TabBarView.

#flutter #mobile-apps #web-development #programming #developer

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Buddha Community

Flutter Widgets (TabBar & TabBarView) The Whole Picture

Destiny Volkman

1597014000

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.

sksl_warm-up

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.

flutter_autofill

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.

flutter_DatePicker

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:

#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

Terry Tremblay

1598396940

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-mobile-desktop-web-embedded_min

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.

humming_bird_dart_flutter

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.

Flutter as a service

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

Aliyah Satterfield

1591643580

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.

Elliott Owen

1626913620

Exploring Flutter Widgets || Flutter Scaffold Widget & Its Properties #16

In this video I have discussed about Scaffold widget and its different properties.

It is a widget which implements the basic material design structure for the flutter app.

#flutter #exploring flutter widgets #flutter scaffold widget #its properties