7 Mistakes To Avoid When Developing Flutter Apps

Created and developed by Google, Flutter is an open-source software development environment and kit that is utilized while designing the user interfaces (UI) for various mobile applications. Its functionality extends to all the popular Operating Systems out there including Android, Linux, iOS, Windows, Mac, as well as Google Fuchsia. 

Launched and unveiled in the year 2015 at the Dart developer summit, the very first version of this development kit went by the codename of “Sky” and ran exclusively on Android. At the time of its unveiling, Flutter packed the potential of consistently delivering a rendering speed of around 120 frames per second.

Over time, this cross-platform development kit has become a raging success among the developer’s community. It has been subsequently made use of to develop a horde of highly potent and innovative apps that have found widespread application in our day to day lives. Although the whole process of developing an application using Flutter is highly rewarding and rather exciting, it comes with its fair share of challenges as well. 

As a beginner, if one does not steer clear of these obvious roadblocks, then they risk not only the integrity of the application they’re building but also the learning curve that they are supposed to imbibe in the process. Listed below, thus, are a few hurdles that app developers should be on the lookout for and try to avoid while using Flutter to develop their apps. 

1. Keeping the cost of build() in check:

One of the foremost mistakes that flutter developers can avoid during the course of making their app is to make sure to not include costly and repetitive work in their build() methods. The reason behind doing so is because build() can be frequently invoked during the rebuilding of ancestry Widgets. Additionally, developers should also try and avoid the usage of single Widgets that are excessively large whenever they are invoking a large build() function into place. Instead, what they can do is split these inordinate widgets into different modular ones. 

This splitting mostly occurs on the basis of encapsulation but is not limited to it. Sometimes the splitting also takes place depending on how these widgets change. For example, when one calls setState() on a State the rebuilding of every descendant widget takes place. Hence, in this situation, developers are advised to localize and narrow down the setState() call to only that portion of the subtree whose User Interface (UI) is in dire need of a change. 

2. Using effects only when necessary:

At the outset, all flutter developers are advised to be extremely judicious in their usage of effects for they can end up taking a heavy toll on their projects. This is primarily because some of these effects call the saveLayer() method in the background which in turn can prove to be a rather expensive operation owing to the fact that whenever a saveLayer() method is invoked it inevitably allots an offscreen buffer. 

Consequently, whenever one makes an attempt to draw any kind of content into this offscreen buffer, the render target switches, which are distinctly slow in former GPUS, end up getting triggered. Hence, there are some general rules that a developer must abide by while developing their app on flutter. They are as listed below:

• Make use of the Opacity widget only when it is absolutely necessary to do so. In other cases, applying opacity straight to an image is considered to be a much faster alternative than employing the Opacity widget.

• Use the clipping function with caution. Unless explicitly requested alongside Clip.antiAliasWithSaveLayer, the clipping function usually does not invoke the saveLayer() method. By default, this function stands disabled at all times and should be enabled explicitly whenever the user has a need for it.

3. Avoiding Syntactic errors:

Sometimes the design falters on account of not abiding by the environment’s inherent syntax. For example, in Flutter, the dart language that is used is case-sensitive in nature. Additionally, one is also required to be very careful while defining parentheses in Flutter while declaring methods. Improper usage might lead to unresolvable syntactic errors. 

Further, In the case of Flutter, an unfamiliarity with its developmental environment causes creators to produce applications that offer a dismal user experience. Learning to avoid declaring top-level variables to limit access to Dart variables only, adding imports whenever they’re necessary, and declaring assets and dependencies under pubspec.yaml are some tips that the developers can keep handy in order to make the most out of Flutter. 

4. Maintaining the code properly:

Often, despite having top-notch engineers, resources, and budgets at their disposal, apps fail to succeed in the market owing to the dismal user-experience that they eventually deliver. This is because, more often than not, not enough time is devoted to sealing their optimization. In Flutter, optimization can be easily achieved by making sure that your code is strictly intended as per the Dart Language guidelines. 

This is done to eliminate the inconvenience and the unreadability that poorly maintained code brings with itself. Additionally, by carrying out certain adjustments for those indices that start with zero, an extra degree of optimization is achieved. Moreover, measures such as employing parentheses only when they’re essential to the framework goes a long way towards enhancing the eventual functionality. Consequently, these factors work collectively towards decreasing the loading time for your Flutter app.

5. Using lazy methods to render lists and grids:

Often while building large lists and grids, developers are increasingly encouraged to combine lazy methods along with callbacks to accomplish their objectives. This way, one can ensure that only the visible segment of the screen develops at the time of startup.

 Additional good practices include giving rise to a ListView that loads only a single page at a time and making use of the Listview.builder API as well. Further, always make sure to add the itemCount parameter to your Listview.builder for in its absence the list of items will tend to be never-ending. 

6. Displaying and building frames in 16ms:

The flutter development environment allows for two separate threads, one each for rendering and building. Should latency happen to be a concern within your framework, then you are advised to render and display the frame in either 16ms or less. 

Additionally, employing 16ms for every individual constituent stage in the build and render pipeline helps the developer to resolve concerns of jankyness as well. Although reducing the render time of the frame below 16ms might not seem to affect a visual difference, it contributes significantly towards enhancing battery life and resolving thermal issues.

7. Taking performance considerations into account:

Certain measures such as avoiding the usage of the Opacity widget in animation, and implementing a subtree in the builder function that is responsible for building widgets that do not concern themselves with animation, while using an AnimatedBuilder, go a long way towards not only avoiding certain pitfalls but also improving the overall performance of your Flutter application.

Designing an application is as exhausting a process as it is rewarding. While the correct application holds power to change and transform our daily lives truly, an ill-executed app ends up being a drain on your time and resources, besides incurring the apparent financial losses. It is crucial, therefore, to be well aware of all the possible challenges that arise during this process so that you can effectively dodge them during the eventual course of developing the application.