15 frequently asked Flutter interview questions

Posted on: December 31, 2020 by Deven

Most individuals fear job interviews. As a result, adequate preparation before the interview is important. Therefore, in this article, we shall discuss the most asked Flutter Interview questions.

Most importantly, this is to help boost your confidence during the flutter interview.

Most noteworthy, here are some of the 15 frequently asked flutter interview questions:

1. What is Flutter?

Flutter is an open-source Google UI that supports the building of beautiful native applications for desktop, web, and mobile from a single code.

2. Name some of the popular apps that use flutter?

Many organizations across the world are building apps using flutter. This is due to, its ability to build native apps in varied categories. Therefore, the most popular apps built with flutter are;

Firstly, Google Ads for utility bills.
Secondly, Reflectly on lifestyle.
Alibaba for commerce
Birch Finance
Coach Yourself
Tencent
Watermaniac
Cryptograph
SG Bus tracker

flutter interview questions — apps built using flutter

3. How would you advise a novice programmer who wants to start building mobile apps using flutter?

This interview question has two dimensions that can be answered.

One important aspect to remember is that Flutter relies on iOS and Android projects. Therefore, it of great importance, if the novice developer is familiar with the project structure of Android and iOS. Certainly, for one to write any native code using flutter, they must have experience with either or both platforms.
Generally, flutter is easy and nice to code in. For that reason, it has fewer codes as compared with Android iOS for the same pages. Hence, for developing apps it will be easy and there will be no much difficulty.

4. Name the best editors for flutter development?

Flutter IDE and tools make flutter development faster, therefore, boosting the developer’s workflow. Above all, flutter IDE and tools are good for developing mobile apps. As a result, you will need some plugins. Usually, the plugins help with Dart compiling, code analysis, and flutter development.

Therefore, the best editors for flutter development are; Android studio and VS code.

5. What are flutter widgets?

A flutter app is said to be having a tree of widgets. Normally, developers build the entire UI by composing smaller widgets to form complex widgets, pages, and a hierarchy of pages.

This process is known as composition over inheritance principle in object-oriented programming.

There are two types of widgets that can be created in the flutter, firstly;

Stateless widgets

Stateless widgets can only be drawn once. When the widget is loaded, as a result, it cannot be redrawn in case of events or user actions. Despite that, stateless widgets are still important. Furthermore, they help in displaying static content which calls for multiple times reloading within an app.

Stateful widgets

This type of widgets maintains the state that might change during the lifetime of the widget. Above all, setState() should be called to help change the state of a StatefulWidget. As a result, the widget is then withdrawn.

6. Is flutter limited to the mobile world only?

No, flutter is not only for the mobile world. Despite the fact that flutter is not officially supported by Google, developers can create desktop apps using it.

7. What are the advantages of flutter?

There are several benefits associated with using flutter. For that reason, I advise you to use it in your next project and see the advantages.

Particularly, below are some of the benefits of using flutter;

It provides the same UI and business logic in all work platforms. Currently, no application framework that supports the sharing of both UI code and UI itself except Flutter.
Shorter code development time.
It has a flexible and expressive UI.
The capability to customize an animated UI of any complexity.
Additionally, flutter has its own rendering engine.
Furthermore, flutter also supports cross-platform development.
Lastly, its potential ability to go beyond mobile, makes it useful in other capacities.

8. Between flutter and react native which one is better?

This a simple but quite tricky flutter interview question. First of all, Flutter and React Native is used in developing hybrid native apps for iOS and Android from a single codebase.

React Native is older in the market since it was released on March 26, 2015. While flutter was introduced in May 2017.

Consequently, it is difficult to choose the best between the two, because, all of them have great features.

Therefore, the developer has the duty to decide on which one to use while running a project.

9. From a business perspective, would say Flutter is a good solution?

Yes, it is a good solution business-wise. There are several factors that inflict drastic value for a business. For example, performance and stability of a platform, a wide talent pool, and room for further development.

As a result, any problems in the platform related to the above-mentioned aspects ignite the occurrence of risks which in turn results in an indirect or direct financial loss to the company.

It is from this perspective, that flutters come in handy, because of the following reasons;

Ease of finding engineers who can professionally use Flutter.
Because of Fuchsia OS created by Google, product development problems are reduced while using flutter.
Ease of integration since there are several companies using Flutter.

10. Briefly, explain the steps of writing a flutter app?

Creating a flutter app is simple. As a result, the developer must be familiar with basic programming and object-oriented coding.

The following are the steps to follow while writing a flutter app;

Creating the starter flutter app– the developer should create a simple templated flutter app.
Apply an external package– in this category, the developer should start using an open-source package known as english_words. This package has some utility functions and thousands of English words.
Addition of a stateful widget– This step is important, because, it helps in maintaining state that might change during the lifetime of the widget.
Creation of an infinite scrolling ListView– This stage involves the expansion of RandomWordState which helps in generating and displaying a list of word pairings.
Lastly, profile runs– After finishing, it is important to analyze the performance of the created app.

11. Why does the first Flutter app build take so long?

During the first time flutter app development, a device-specific APK or IPA file is created. Consequently, XCode and Gradle are used in building the files, thus, taking time. Thereafter, when the app is restarted, flutter patches the changes on the existing app, resulting in, a super-fast refresh.

12. How do you handle indentation and structure in Flutter code?

First of all, it is important to note that Android Studio has tools that make structuring flutter code simple.

Hence, the two main aspects are;

Alt + Enter/ Command + Enter

This enables developers to wrap, swap, and remove widgets in a complex hierarchy. To find this, direct your cursor to the widget declaration and click on the keys to access more options.

DartFMT

DartFMT is great since it formats your code to ensure a clean identification and hierarchy.

Additionally, it makes your codes easier to work with by just playing with a few brackets.

13. Why are functions passed to widgets?

Normally, functions are passes to the widget if they give the response, “invoke this function when something happens”. In Dart, functions are first-class objects and can be passed to parameters of other functions.

Finally, interfaces that use Callbacks have much boilerplate code for a normal callback.

Java callback

utton.setOnClickListener(new View.OnClickListener() {
    @override
    public void onClick(View view) {
      // Do something here
    }
  }
);

Dart Equivalent

FlatButton(
  onPressed: () {
    // Do something here
  }
)

14. Is drag-and-drop easier than making a layout in code?

This is a challenging flutter interview question. To some extent this is true. Most flutter developers will settle for coding options. Similarly, that does not mean that drag-and-drop is impossible for flutter community to implement.

Above all, if your preference is drag-and-drop, the Flutter Studio is a resourceful tool that will help you generate layouts.

15. Why are there Android and iOS folders in the Flutter project?

Currently, there are three main folders in the Flutter project; android, lib, and ios. The ‘lib’ is important because it takes care of Dart files.

While the Android and iOS folders help in building apps on those respective platforms with the Dart files running on them. Furthermore, they help in adding permissions and platform-specific functionality in the projects.

When running a Flutter project, it builds depending on which emulator or device it is running on, doing a Gradle or XCode build using the folders inside it. As a result, the folders are entire apps that set the stage for the Flutter code to run.

Conclusion

It is my hope that this article has been of great help to your flutter interview preparations. But remember also to check on other basic interview questions. Since the flutter interview will have both technical flutter questions and general interview questions. Feel free to like and drop a comment.