November 22, 2017 3198

Google’s all-new programming language ‘Kotlin’ is an open source and statically-typed, running on the Java Virtual Machine. It combines object-oriented and functional programming features for the JVM and Android development. Moreover, it mainly focused on interoperability, security, and tooling support.

With the Kotlin Android development, it becomes easily possible for developers to separate functionality and business logic using extensions. Now, they can save hours of development time using Kotlin.

Across the world, a lot of developers found this language extremely helpful because of these benefits, and therefore, they have employed Kotlin as their first programming language for android application development. According to Google, over 50% professional Android app developers use Kotlin to develop their Android mobile apps.

While discussing Kotlin, one of our experienced android developers shared some of the top and advanced Kotlin tips. So, if you are planning to create an android app using Kotlin or do you want to know more about this programming language, check out the below-given tips that are helpful to anyone, who uses Kotlin.

Tips for Developing Android Apps Using Kotlin

1. Using Lambdas

When it comes to talking about Lambdas, they are one of the most powerful tools in Kotlin for Android, and in any other modern language, since it enables modelling functions in a much simpler way.

Lambdas, and mainly the way they are defined in Kotlin, open-up an infinite world of possibilities. It is a way of representing a function and here is one example of using Lambdas:

Remove boilerplate codes -> for example button.setOnClickListener(new View.OnClickListener() { // JAVA CODE @Override public void onClick(View view) { //Your Operation. } }); button.setOnClickListener { // KOTLIN CODE //Your Operation. }

2. Say Goodbye to findViewByld

You might get bored of using findViewByld on daily basis to recover Android views. And, you have already started using Butterknife library or any other option. Then, you will love Kotlin Android Extensions.

Kotlin Android Extensions are another Kotlin plugin, included in the regular one. The plugin will enable you to recover views from Activities, Fragments and Views in an amazing seamless way.

The plugin will generate some extra code that will allow you to access views in the layout XML, just as if they were properties with the name of the id you used in the layout definition.

Integration Steps: Put this lines at the top of Application Gradle file and Build the Project

apply plugin: 'com.android.application' apply plugin: 'kotlin-android' apply plugin: 'kotlin-android-extensions'

Get complete example here.

3. Null Safety

Kotlin has two different types of references that are interpreted by the compile to deliver the programmer information about the correctness of a program at compile time – those, which are nullable and those, which are not.

Elvis Operator !! Operator var a: String = "abc" a = null // compilation error

To allow nulls, we can declare a variable as the nullable string, written String?:

var b: String? = "abc" b = null // ok

However, the other option is for NPE-lovers. We can write b!!, and this will return a non-null value of b (e.g., a String in our example) or throw an NPE if b is null. Get the detailed example here.

4. Safe Type Casting

Many a time in Android mobile app development, normal typecasting causes an exception. Hence, safe typecasting is surely required and mainly for creating a Fragment in an Activity.

For example:

var typeFragment: TypeFragment? = supportFragmentManager .findFragmentByTag(TAG_FEED_FRAGMENT) as TypeFragment

Here, we are casting TypeFragment without checking that whether it is actually a TypeFragment or not. In case, if it is not, it will cause a problem. However, there is no need to bother as Kotlin has introduced safe typecasting.

Instead of using as we need to use as? It will safely cast fragment and won’t throw an exception.

var typeFragment: TypeFragment? = supportFragmentManager .findFragmentByTag(TAG_FEED_FRAGMENT) as? TypeFragment

It will check if your fragment is not typeFragment, then it will return null -> so it won’t directly throw an exception.

5. Leveraging let

Leveraging let permits you to execute a block if the value of the object is not null. This allows you to avoid null checks and makes the code more readable. In Java it looks like this:

if (object != null) { // JAVA CODE //Your operation }

But in Kotlin, it looks like this:

object?.let { // KOTLIN CODE //Your operation }

6. Converting Java Code to Kotlin

Now, you can easily convert your whole Java class into Kotlin and Piece of code. To convert Piece of code, you just need to Copy the code from Java class and paste it into Kotlin file it will ask you to convert it to Kotlin Code -> Press Yes.

Also Read: Kotlin vs Java – Which is better for Android app development?

It is highly helpful for kotlin Android developers as it becomes handy if they are new to Kotlin and don’t know the exact syntax for Kotlin.

7. Coroutines Instead of AsyncTask

As you know that AsyncTask causes Memory leaks many a time and it is quite difficult to handle in Java. Bit in Kotlin, Coroutines is a perfect alternative that is lightweight that can be used without worrying about Memory leaks.

fun bindUser() = launch(UI) { // Some long running operations like -> Network requests val details = MyApi.getMasterdata().execute() // Access UI at the same time. Text.visible = false }

Talking about the performance and lightweight of Coroutines, one study says that 1000 coroutines are equal to 1 thread of Java. Running multiple coroutines parallelly is easily possible without any performance issue.

8. Parcelize

It allows you to reduce the boilerplate code. The feature of percelize library helps to get rid off terrible performance. From now on, there is no need to make use of libraries like EventBus or Otto, although they are easy-to-use & have amazing performance, however, they cause too much complexity in the code.

It is a great interface for better Android performance. The programming language – Kotlin added Parcelize in the version 1.1.4 or newer. This android extension consists of an automatic Parcelable implementation generator.

In addition, this feature lets you declare the serialized properties in a primary constructor & include a @Parcelize annotation and methods such as writeToParcel()/ createFromParcel() as they will be created automatically.

Now, look at the code, which is generated in JAVA –

public class User implements Parcelable{ private String name; private String gender; private String address; // Constructor public User(String name, String gender, String address){ this.name = name; this.gender = gender; this.address = address; } // Getter and setter methods ......... ......... // Parcelling part public User(Parcel in){ String[] data = new String[3]; in.readStringArray(data); // the order needs to be the same as in writeToParcel() method this.name = data[0]; this.gender = data[1]; this.address = data[2]; } @Оverride public int describeContents(){ return 0; } @Override public void writeToParcel(Parcel dest, int flags) { dest.writeStringArray(new String[] {this.name, this.gender, this.address}); } public static final Parcelable.Creator CREATOR = new Parcelable.Creator() { public User createFromParcel(Parcel in) { return new User(in); } public user[] newArray(int size) { return new User[size]; } }; }

Isn’t it a long & unended one?

And now, have a look at this code, which is curated with the help of Parcelize –

@Parcelize data class User(val name: String, val gender: String, val address: String) : Parcelable @Parcelize data class User(val name: String, val gender: String, val address: String) : Parcelable

The Above one is precise & can save a lot of time of yours along with the better performance.

In a nutshell, it’s time to apply Parcelize if you are looking for something that could save a huge time with enhanced & better performance.

Conclusion

In short, Kotlin for Android development is a completely idolized programming language that is known for its simplicity and a cleaner working platform. And these are the top 8 Kotlin tips for Android app development that are shared by one of our Android app developers, who have already researched and started working on Kotlin.

Still, if you have any confusion related to Kotlin and managing your Android project, you can get in touch with us as we are a leading Android app development agency based in India, and specialized in developing android apps.

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This page was last edited on April 29th, 2020, at 9:31.