How To Add Null Safety In Flutter

How do you turn on null safety in flutter?

– Click on ” main.dart ” at top of IDE, and click on ” Edit Configuration “. Note: You need to add Flutter and Dart plugin on android studio, otherwise this menu is not available. Copy: -no-sound-null-safety and add into ” additional run args “. Run your app with ” Run/Play ” Button or from ” Run ” Menu. In this way, you can solve ” Error: Cannot run with sound null safety, because the following dependencies don’t support null safety” error on Flutter project. : Cannot run with sound null safety Error in Flutter

What is null safety in flutter?

Sound null safety Contents

  • The Dart language enforces sound null safety.
  • Null safety prevents errors that result from unintentional access of variables set to null,

For example, if a method expects an integer but receives null, your app causes a runtime error. This type of error, a null dereference error, can be difficult to debug. With sound null safety, all variables require a value. This means Dart considers all variables non-nullable,

You can assign values of the declared type only, like int i=42, You can never assign a value of null to default variable types. To specify that a variable type can have a null value, add a ? after the type annotation: int? i, These specific types can contain either a null or a value of the defined type.

Sound null safety changes potential runtime errors into edit-time analysis errors. With null safety, the Dart analyzer and compilers flag if a non-nullable variable has either:

  • Not been initialized with a non-null value
  • Been assigned a null value. These checks allows you to fix these errors before deploying your app.

What version of Flutter SDK for null safety?

Check whether your project uses null safety – In order to know if your project is using null safety or not, go to your pubspec.yaml file and check under the environment section for the Dart SDK version currently in use by your project: environment: sdk: “>=2.10.0 If your SDK version on the left is equal to or less than 2.10.0, then you currently do not have null safety enabled in your project. On the other hand, if your version number is 2.12.0 or higher, then you have null safety enabled in your project.

What is null safe check?

NullPointerExceptions (often shortened as “NPE”) are a nightmare for every Java programmer. We can find plenty of articles on the internet explaining how to write null-safe code. Null-safety ensures that we have added proper checks in the code to guarantee the object reference cannot be null or possible safety measures are taken when an object is null, after all,

How do I enable null safety in Dartpad?

You can enable or disable Null Safety in dartpad by setting the query parameter in the URL null_safety to false. To disable null safety in dartpad, go to

What is null check in Dart?

Improve Article Save Article Like Article Improve Article Save Article Like Article Null-aware operators in dart allow you to make computations based on whether or not a value is null. It’s shorthand for longer expressions. A null-aware operator is a nice tool for making nullable types usable in Dart instead of throwing an error.

  1. These operators are used in fullback in combination that you will get value at the end but not null.
  2. Null-aware operators are used in almost every programming language to check whether the given variable value is Null.
  3. The keyword for Null in the programming language Dart is null.
  4. Null means a variable which has no values assign ever and the variable is initialized with nothing like.

The most common use of the Null aware operator is when a developer wants to parse JSON data from the server and after parsing JSON, the user can check whether the JSON is empty or not using the IF-Else condition. Here are few Null-aware operators that are explained.

How do I run Flutter Vscode without debugging?

Click Run > Start Without Debugging in the main IDE window, or press Ctrl + F5.

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How do I secure my API key in Flutter?

What about Obfuscation? – So far, we’ve managed to generate a tmdbApiKey constant from our,env file. But this is still stored in plaintext, and if an attacker tries to reverse engineer our app, they may be able to extract the key. To make our API key more secure, we can use obfuscation,

  1. This is done by adding the obfuscate: true flag in the @EnviedField annotation: import ‘package:envied/envied.dart’ ; part ‘env.g.dart’ ; @Envied ( path: ‘.env’ ) abstract class Env Any variables annotated with the obfuscate flag should be declared as final (not const ).
  2. Then, we can re-run the code generation step: flutter pub run build_runner build – delete – conflicting – outputs And if we inspect the generated env.g.dart file, we’ll see that the API key has been obfuscated: // GENERATED CODE – DO NOT MODIFY BY HAND part of ‘env.dart’ ; // ************************************************************************** // EnviedGenerator // ************************************************************************** class _Env Excellent! The API key is no longer hardcoded, making it much harder to extract if an attacker decompiles our app.

🚀 See the Usage section of the ENVied package to learn how to use it with multiple environments/flavors.

Is Flutter a no code tool?

Which is the best Flutter no code app builder in 2023? As mobile app development continues to rise in demand, the tools and technologies used for app development continue to advance at a rapid pace. Among these, no-code app builders have gained increasing popularity as they enable developers and businesses to create mobile apps quickly and easily without requiring extensive programming knowledge.

There are many app builders that use different frameworks for app development like Flutter, Kotlin, React Native, etc. Now, which one is better among them, or whatever, that is a different topic altogether. We will focus on Flutter-based app builder today. One such no-code app builder is Flutter, which has become increasingly popular among app developers for its simplicity and ease of use.

In this blog post, we’ll explore the concept of building no-code Flutter apps and how they can benefit developers and businesses alike. is a top-tier Flutter app Builder that stands out in the current market. It can create awesome Flutter apps with minimal use of code, custom app Logics, and comprehensive Backend support.

  1. Look no where else than one and only Blup.
  2. With BlupDesigner, Revolutionize the way you develop mobile apps with Blup’s Drag and Drop builder! This dynamic tool empowers you to effortlessly craft striking, high-functioning app pages in record time.
  3. Bid farewell to dreary coding and design work, and say hello to fluid, eye-catching results that will captivate your users.

Brace yourself to work up to 10x more efficiently and elevate your mobile app to new heights! With Blup Logic, Transform your app development process with our innovative visual logic creator. Say goodbye to the frustration of coding and hello to effortless logic creation that powers your app’s widgets. Our game-changing tool helps you create dynamic logic in a snap, resulting in lightning-fast performance that will delight your users.

Discover how our cutting-edge visual logic creator can take your app to the next level. Enter the next era of data management with Blup Backend – an advanced GUI-based database built to perfectly complement Blup. Our easy-to-use tool lets you quickly load and save data, ensuring that your data is always secure and accessible.

Say goodbye to complicated data management and hello to Blup Backend. Blup makes app publishing easy – with just a few clicks, you can publish your app to both the Apple Store and Play Store, reaching millions of potential users worldwide. With Blup, the possibilities are endless.

Whether you’re a seasoned developer or just starting out, Blup’s intuitive interface and powerful features will help you take your app to the next level. Don’t wait – and start your journey towards app success! Also, Blup can be used as an ideal Coming on the second position, has a no-code UI builder that is designed to cater to both beginner and experienced developers alike.

With its intuitive drag-and-drop interface, users can effortlessly create the on-page features of various mobile application screens. In addition to its user-friendly interface, also boasts a day and night mode, making it an ideal tool for developers who work round the clock to ensure timely launches of mobile applications for their clients. One of the most appealing aspects of is its flexibility. Whether you have a wealth of coding experience or none at all, the platform allows for customizations that can be easily made to suit your needs. Furthermore, supports multiple languages, giving users the freedom to create and design mobile applications in a variety of languages.

With API integration also on offer, the possibilities are endless. Explore the extensive features of and decide whether it is the perfect UI builder for your next project. Based on the free plans and features, FlutterViz offers a decent Drag and Drop UI Builder, It is useful for those who are starting out in the app development business.

With its easy-to-use interface, even individuals with zero coding experience can create professional and practical user interfaces for mobile applications. Using Flutter UI Builder Drag and Drop frees up developers’ time that would otherwise be spent developing repetitive features multiple times to meet clients’ demands. FlutterViz also offers preset and starter screens to provide developers with a solid starting point for creating a user interface for a new mobile application. Additionally, there are multiple ways to add images to create a mobile user interface that aligns with your clients’ brand Flutter UI Builder Online is a useful tool for anyone who can use a computer, regardless of their preferred language for working.

FlutterViz even has day and night modes to facilitate longer working hours for developers working during different time durations. Even without any prior coding experience, you can create an impressive and effective user interface for your mobile applications using Flutter UI Builder FlutterViz. With tutorials to guide you at each step, the process is streamlined and easy to follow.

Explore the various features of FlutterViz and see how this powerful tool can give your development a much-needed boost. If you are looking for other options, Adalo is helps developers to build mobile and web applications with ease. With its intuitive drag and drop components, creating advanced and user-friendly interfaces for different screens required for mobile or web applications is a breeze.

While most of Adalo’s features are focused on the frontend part of an application, on-page logic can trigger backend events when required. This makes it a great choice for developers who want to create beautiful and functional user interfaces without worrying about complex coding. Moreover, Adalo can be integrated with other tools and APIs to develop both front-end and back-end features of mobile and web applications.

With Adalo, developers have a powerful tool at their disposal that can simplify the app development process and help bring their ideas to life. Take a closer look at the various features of Adalo’s no-code UI builder to explore the full potential of this tool for your app development needs. Since is an online builder, you can access it from any device and create visually stunning applications that function flawlessly. It even offers a variety of sign-in options and lets you save your designs for future access. Plus, with its comprehensive database and analytics, you’ll have access to valuable insights that can inform your app updates. is particularly useful for those just starting out in mobile app development or UI design. So, if you’re looking for an online UI builder that can help you create beautiful and functional interfaces for mobile apps, might just be the perfect fit for you. Try and see for yourself! Apart from this, we have written other in-detail articles on Flutter and mobile app development.

You can find them below: We hope you read the ones you like and share them. See you later! : Which is the best Flutter no code app builder in 2023?

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How do I add an SSL certificate to Flutter?

Ensuring Secure Communication in Flutter Applications Using SSL Pinning Techniques – Outline

IntroductionSetting up a Flutter projectImport Certificate from WebsiteAdding SSL Pinning to ProjectTesting SSL Pinning ImplementationSummary

When using HTTPS, the server automatically creates a certificate and sends it to the app. However, the app will accept any certificate it receives, making it vulnerable to a man-in-the-middle attack (MITM) where a hacker intercepts the client-server connection and adds some bad certificates that can lead to data breaching and leakage of private user information. This can be a security concern. SSL Pinning will create trustable SSL certificate connection between the server and the client. This way, an additional validation is in place to check whether the certificate stored in the application is the same as the one used by the server. If the certificate does not match, the application can reject it.

NewsApiService will have property client that will be injected later it will make it easier to change the implementation of our http Client when we want to use client that implement SSL Pinning.FetchArticle method will try to call web service, if status code 200 (success) it will return model that converted from json body, if not it will throw Error

Step 2 Create a Home Page We need to create home page for our flutter application that will consume NewsApiService and showing the article information void main() class MyApp extends StatelessWidget ); // This widget is the root of your application. @override Widget build(BuildContext context), itemCount:, ); } else }, ), ), ); } } Explanation

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In main() we initialize NewsApiService that pass http.Client (we will change this later with Client that impelement SSLPinning )It will get data from NewsApiService via FutureBuilder If data exists it will show ListView with news information otherwise it will show loading indicator

We need to download the SSL certificate used by the server. There are two way to get SLL Certificate used by the server

Command LineExport from Browser

Command Line Open your terminal and type command below openssl s_client -showcerts -connect -servername 2>/dev/null certificate.pem It will get certificate from and save it into your desired directory & file name. For the command above the file will be stored in that directory with the name certificate.pem Export from Browser To download the SSL certificate from Broweser, open the endpoint or base url of the API that we call from the application and then open it in the browser, Click padlock icon -> Connection is Secure -> Certificate is Valid After a new Ceritifc Viewer window appears, we can click details and click export button and save the certificate into our project In this case, we will save our certificate into assets directory, so our project structure will look like below asset – certificate.pem lib test pubspec.yaml We already have certificate.pem the next step is we will use that certificate into our project. Step 2 Create Future to Load Certificate Create a future method that will be used to load certificate.pem from our asset and set the certificate into SecurityContext. By setting SecurityContext with our certificate, SecurityContext will not trust the OS’s certificate, instead if will load our certificate file and trust the our certificate.

Future get globalContext async Create a method that return http.Client in this method we will initialize HttpClient instance that will contain our ceritifcate.pem information Future getSSLPinningClient() async Refactor our main() method that will use getSLLPinningClient instead of http.client Future get globalContext async Future getSSLPinningClient() async void main() async Use Valid Certificate We already implement the SSL Pinning into our project, So, let’s try this out.

When we are hitting newsapi.orgi with the certificate we pinned our application will be able to fetch news data and show it to our home page Use Invalid Certificate If we use invalid certificate or the certificate is expired we will not able to connect into our server, it wil throw the exception like below To fix that issue we need to renew our certificate.pem file and our application will run smoothly. SSL pinning is one of the ways to secure communication between the mobile device and the server. It explains that while HTTPS creates a certificate and sends it to the app, apps can accept any certificate they receive, making them vulnerable to man-in-the-middle attacks.

How do you check if a string is null Flutter?

Check if a String is empty or null in Dart / Flutter In this post, we are going to explain how to check if a String is empty or not. We will also cover if the given value is null, false, or 0. If you are using Dart or Flutter to create your application, you can use the code examples listed here. void checkString(String str) else } void main() Explanation of the above code example

Created a function checkString that takes the string value as a parameter.Inside the checkString() function, we are using String.isEmpty and it will print ” String is empty ” if the string is empty.Testing the above function for two values ” and ‘ hello ‘.

Check if values are null, empty, false using List.contains() function void checkString(value) else } void main() : Check if a String is empty or null in Dart / Flutter