Kotlin was launched to advance Android development by making the creation process easier and faster. Once it became an official language for Android, it has taken over Java’s position as the first choice for many Android developers.
Taking into account their resemblance, the adaptations to Kotlin must have been easy for Java developers. Nevertheless, one should also take notice of the differences or rather conversational components of Kotlin at the same time. Certain adjustments are necessary to be able to write code as same as Java.
Popular Apps started to apply Kotlin for its new Android projects late in 2016, that is, when Kotlin 1.0.4 was first released. Originally, Kotlin was tried out on smaller scale projects and successfully seen to simplify the use of databases and showed the potential to break the components from business logic with the help of various extensions. Since, as a results, great amount of time taken for development was saved, the developers made the decision to make Kotlin the language of choice moving forward. And following this, the language also was used to develop multiple Android apps, forming a number of internal Kotlin libraries.
In order to establish your first encounter with Kotlin, we have gathered the most useful and important tips. Before we start going through these tips, you should know that these points specifically consider utilizing Kotlin within the context of Android development. Having some experience with the Android SDK and being familiar with the concept of Kotlin plugin would also help. Using Kotlin with Android Studio is provided by Jet Brains, the company-creator of Kotlin.
Basic Kotlin Tips for Android
There are certain advantages that come along with delayed or lazy loading. Lazy loading normally results in accelerated start-up time. Since loading is delayed when the variable is called, this is particularly helpful in using Kotlin for an Android app. For Android apps, the developers prefer taking the edge off the app start-up time with the intent that the user sees the app content faster, rather than staring at start loading screen.
Delayed loading is also known to be more memory structured, as the developers direct the resources into memory only if it is addressed. Thus, memory usage is a very scheduled and timely on mobile platforms such as Android as the phones have limited, distributed resources.
Kotlin’s custom getters and setters are used to regulate the structure of a model. At the same time, you are expected to state the custom behavior to get and set the domain. Let’s say, you are applying custom models for particular frameworks, just like the Parse SDK. In doing so, you are introducing values that would not be local variables in the class. Yet, they are located and retrieved from in a custom way, typically from JSON.
USE OF LAMBDAS
Lambdas are used to shrink the lines of code located in a source file. It also great to convey the purpose of functional programming. While lambdas are at present available in Android, Kotlin also makes sure that you don’t have to operate with Retro lambda or optimize the pattern in which your build is established.
The Android SDK consists of a great variety of cases where you are optimizing a listener or running a single method. And Lambdas work error-free in those cases.
Simple classes or Data classes separate the classes, adding equals(), hashCode(), copy(), and toString() formula automatically. They also add specific clarification in the purpose of the model and what should go in it by dividing clear data from business logic.
If you are using data classes with something like Gson or another JSON parsing library, you can go with the default constructor by applying only the default values.
Collections are regulated multiple times when working with an API. To put it simply, it is advised to to filter or bring modification to the contents of a particular collection. Thus, by activating Kotlin’s collection filtering, you will be able to add some clarity and make your code more to the point. It would also be easier to see what your resulting list should consist of using the collection filtering option.
Modifying a collection with this built-in Kotlin method is very correspondent to other functional programming languages, such as Java 8 streams or Swift collection types. Going through the collections in a unified patter helps to organize team-work and discuss what operations need to be made to get a list down to the right features to present.
Object expressions enables strict singleton definition so there is no misreading it for a class that can be consolidated. They also make sure that you do not have to additionally collect and place those singletons somewhere similar to the Application class or as a static class variable.
ADVANTAGE OF COMPANION OBJECT
At first glance, Kotlin seems to be lacking static variables and methods. In a way, it does not have these concepts, but holds on to the intention of companion objects. These companion objects act like singleton objects inside a class, meaning that they comprise of the methods and variables you might have to access in a static manner. A companion object allows to define constants and methods, similar to static in Java. With it, you can enable the newInstance technique of pairing.
ACCESING GLOBAL CONSTANTS
Kotlin lets you define constants that spread over an entire app in one place. Typically, constants should have their extent cut down as much as possible. Nevertheless, if scope needs to be global this would be the optimal way to do so without having to undertake a constants class.
Alternative or optional parameters make technique calls more flexible without having to pass null or a default value. This is particularly important when setting up animations.
For example, if you need to have a method defined for limiting the views all around your app. Yet, only in these special cases do you need to indicate the duration.
Progressive Kotlin Tips for Android
USE OF EXTENSIONS
Extensions are of great use as they let you add to the components of a class without having to adopt from it. By employing extensions, you can easily omit the need to have utility classes or methods. It can also significantly improve the readability of your code.
A main characteristics of Kotlin is its commitment to null safety. Lateinit property has a simple method that ensures both null safety and division of a variable the way Android requests you to. This is a convenient language feature. Yet it would probably take some time getting used to it after completing extensive Java development.
These features of the language can be heavy when managing Android layouts. This is mainly because we know that the views are going to exist within the Activity or Fragment, but we cannot declare them straight away since it has to be done in onCreate/onCreateView once the layout is distended. It is also possible to handle this by controling checks in each place you access the view throughout the Activity. However, this would be challenging to handle and should be avoided from a null check point of view. Instead, you can use the lateinit editor.
Some Android conventions require a safe typecasting activated due to its default typecasting that would cause an exception. For example, a standard method of building a Fragment in an Activity is to first scan and see if it subsists already, with the help of the FragmentManager.
LEVERAGING KOTLIN FEATURES
Leveraging let enables you to implement a block if the value of the object is not null. This further helps you to stay away from null checks and makes code more comprehensible.
ISNULLOREMPTY | ISNULLORBLANK
Potentially, you would be required to certify several times in the overall development of an Android app. In case you have managed to do it without making the use of Kotlin, you may have addressed the TextUtils class in Android.
The Latest Kotlin Tips for Android
OVERRIDING SINGLE ABSTRACT METHODS
Avoiding single abstract methods enables you to apply lambdas, which results in cleaner, more readable code. For example, when operating in Java, it is normal to add a simple listener class. One of the great characteristics of Kotlin is that it completes SAM (Single Abstract Method) conversions for Java classes.
OPTING FOR COROUTINES INSTEAD OF ASYNCTASK
It is recommended to go with Couroutines instead of Asynctask mainly because the latter is heavy and may lead to leaks. The developers prefer coroutines as they offer better readability and don’t burden the memory. Its crucial to notice that since coroutines are experimental in Kotlin 1.1, the developers still opt for RxJava for most async operations.
We have collected these tips from what is considered to be the most coherent techniques which one should known before getting started with Kotlin. These notes will for sure help you get used to its main features and provide you with a solid start in applying Kotlin for your future Android projects.
- 16 Kotlin Tips for Android Development – SAVVY
- Kotlin: Tips and Tricks Part -1– Medium
- 7 Quick Kotlin Tips for Android Developers – Medium