高橋  陽子

高橋 陽子

1660555695

如何在 Flutter 中輕鬆創建有狀態的 Widget

在本教程中,我們將創建一個按鈕小部件,當按下按鈕時,它將向列表添加一個項目並在移動屏幕上顯示該列表。因此,當按下按鈕時,小部件的狀態將發生變化,UI 將重新渲染,我們將在手機屏幕中看到產品列表。

如果你不知道如何在 mac 上安裝 Flutter,可以查看這篇文章。它將引導您安裝 Flutter 應用程序並在 Android 和 iOS 模擬器上打開應用程序。

如何在 Flutter 中創建有狀態的 Widget

要在顫振中創建有狀態的小部件,請使用 createState() 方法。有狀態小部件是通過構建更具體地表示用戶界面的其他小部件的星座來描述用戶界面的一部分的小部件。

有狀態的小部件是指具有可變狀態的小部件。狀態是可以在構建小部件時同步讀取的信息,並且可能在小部件的生命週期內發生變化。小部件實現者有責任使用State.setState 方法確保在此類狀態 更改時及時通知狀態 。

構建過程遞歸地繼續,直到用戶界面描述足夠具體。

創建新項目後,您的項目結構如下所示。請記住,我使用的是 Flutter 1.0 版。因此,如果您有不同的結構,請檢查您的項目的版本。

如何在 Flutter 中創建有狀態的 Widget

對於這個例子,我們將只更改一個文件,lib >> main.dart 文件。

有狀態小部件的骨架

以下是任何 Stateful Widget 類的基本語法。

class MyApp extends StatefulWidget {
  @override
  State<StatefulWidget> createState() {
    return _MyAppState();
  }
}

class _MyAppState extends State<MyApp> {
  @override
  Widget build(BuildContext context) {
    return Container(color: const Color(0xFFFFE306));
  }
}

因此,首先,我們聲明了名為 MyApp 的主類,它擴展了 StatefulWidget 類。這意味著我們必須在該類中定義名為createState() 的通用方法。

現在,該方法將返回另一個擴展 State 的類。

在我們的例子中,_MyState 類擴展了 State。所以所有與狀態更新相關的編碼都在這個類中。

創建狀態方法

它在樹中的給定位置為該小部件創建可變狀態。例如,下面的代碼實現了它。

@protected
State createState();

有狀態小部件示例

我們舉一個例子,我們將在其中添加一個按鈕和一張卡片。該卡片由一個名為 Text 的小部件組成。因此,當用戶單擊按鈕時,它將向列表中添加一個新項目。所以列表的狀態發生了變化,flutter 會更新它的 UI,我們會在手機屏幕上看到列表。

現在,將以下代碼替換為lib >> main.dart 文件中的現有代碼。

// main.dart

import 'package:flutter/material.dart';

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

class MyApp extends StatefulWidget {
  @override
  State<StatefulWidget> createState() {
    return _MyAppState();
  }
}

class _MyAppState extends State<MyApp> {
  List<String> _products = ['Laptop'];
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(title: Text('First app')),
        body: Column(children: [
          Container(
              margin: EdgeInsets.all(10.0),
              child: RaisedButton(
                  onPressed: () {
                    setState(() {
                      _products.add('PC');
                    });
                  },
                  child: Text('Hello World'))),
          Column(
              children: _products
                  .map((element) => Card(
                        child: Column(
                          children: <Widget>[
                            Text(element)
                          ],
                        ),
                      ))
                  .toList()),
        ]),
      ),
    );
  }
}

List 數據類型相當於 Javascript 語言的 Array。因此,您可以在列表中添加或刪除元素。

在 _MyApp 類中,我們初始化了一個名為 _products 的列表,其中包含一項名為 Laptop。 這就是我們這個演示的狀態變量。

現在,當用戶點擊一個按鈕時,它會調用 setState() 方法,該方法會將新項目添加到列表中,並且由於狀態的變化,flutter 會更新 UI,我們正在迭代一個基於卡片的小部件並查看屏幕上的文字。

如何在顫振列表示例教程中添加數據

當用戶點擊一個按鈕時,我們會看到 每次都會在列表中添加一個PC 項目,您可以在屏幕上以卡片的形式顯示該項目。

所以,這就是你可以在 Flutter 中使用 StatefulWidget 的方式。

鏈接:https ://appdividend.com/2022/03/12/how-to-create-stateful-widget-in-flutter/

#flutter #dart

What is GEEK

Buddha Community

如何在 Flutter 中輕鬆創建有狀態的 Widget

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 RangeSliderDatePicker 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

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

Dream11

NuBank

NuBank

Reflectly app

Reflectly app

Abbey Road Studios

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

Punith Raaj

1644991598

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

Punith Raaj

1640672627

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.