Android Studio 4.0 – the Most Exciting Updates Explained

In the midst of a global pandemic, Google released the stable version of Android Studio 4.0 on May 28, 2020. This major update to the official IDE for Android app development introduces a wealth of exciting new features and enhancements that make it easier than ever for developers to build high-quality apps.

As an Android developer myself, I‘ve been eagerly exploring Android Studio 4.0 since its release. In this article, I‘ll walk through some of the most significant updates and how they can boost your productivity and app performance. Whether you‘re a seasoned Android dev or just getting started, there‘s a lot to get excited about in Android Studio 4.0!

Motion Editor

One of the standout additions in Android Studio 4.0 is the new Motion Editor. This powerful tool provides an intuitive interface for creating, editing, and previewing complex animations in your app using the MotionLayout API.

With the Motion Editor, you no longer have to hand-write elaborate XML files to define MotionLayout animations. Instead, you can visually choreograph intricate motion and widget animations with a few clicks. The editor also provides a real-time preview of your animations, making it a snap to perfect your app‘s motion design.

Here‘s a simple example of how to define a MotionLayout animation in the Motion Editor:

<?xml version="1.0" encoding="utf-8"?>
<MotionScene 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:motion="http://schemas.android.com/apk/res-auto">

    <Transition
        motion:constraintSetEnd="@+id/end"
        motion:constraintSetStart="@id/start"
        motion:duration="1000">
       <KeyFrameSet>
       </KeyFrameSet>
    </Transition>

    <ConstraintSet android:id="@+id/start">
    </ConstraintSet>

    <ConstraintSet android:id="@+id/end">
    </ConstraintSet>
</MotionScene>

In this XML, we define the start and end constraint sets for our animation, as well as the transition between them. The Motion Editor takes care of generating all of this for us based on the animations we choreograph in the visual designer. It‘s a huge timesaver and makes complex animations much more approachable.

Live Layout Inspector

Debugging and perfecting your app‘s UI can be a tedious process, especially when dealing with complex view hierarchies and varying device configurations. Android Studio 4.0 introduces the Live Layout Inspector to help streamline your UI workflow.

With the Live Layout Inspector, you get a real-time 3D representation of your app‘s view hierarchy. This makes it easy to visualize how your layout is structured and identify potential issues like overlapping views or improper alignments.

The inspector also provides detailed information about each view‘s properties and resources, so you can quickly pinpoint the source of any layout problems. And with support for inspecting apps running on devices with API level 29 and higher, the Live Layout Inspector is a versatile tool for perfecting your UI on a range of devices.

Layout Validation

Designing an app layout that looks great across a variety of screen sizes and configurations is an ongoing challenge for Android developers. To help simplify this process, Android Studio 4.0 introduces the Layout Validation tool.

With Layout Validation, you can preview your app‘s layout on multiple screen sizes and device configurations simultaneously, right within the Layout Editor. This makes it easy to catch layout issues early in the design process and ensure your UI looks pixel-perfect on any device.

To use Layout Validation, simply open your layout in the design editor and click the validation button in the toolbar. You can then configure the devices and orientations you want to preview and see your layout rendered across all of them in real-time as you make changes. It‘s a huge productivity booster for perfecting your app‘s responsive UI.

Build Analyzer

Build times are a frequent pain point in Android development, especially as apps grow in size and complexity. Android Studio 4.0 aims to help with the new Build Analyzer tool.

The Build Analyzer provides a detailed breakdown of your app‘s build process, highlighting the plugins and tasks that have the biggest impact on overall build time. It also offers actionable suggestions for optimizing your build configuration to speed things up.

For example, the analyzer might suggest bumping up the heap size for the Gradle daemon, or point out a particular task that‘s taking much longer than expected to complete. Armed with these insights, you can methodically optimize your build process and get back to coding faster.

Here‘s an example of how to enable the Build Analyzer in your app‘s build.gradle file:

android {
    ...
    buildFeatures {
        buildConfig = false
    }
}

With the buildConfig feature disabled, the BuildConfig class won‘t be generated, shaving a bit of time off the overall build process. The Build Analyzer will suggest optimizations like this to help keep your build lean and fast.

Java 8 Language APIs and Desugaring

Java 8 language features can help make your code more expressive and concise, but historically it‘s been challenging to use them when targeting older Android versions. Android Studio 4.0 addresses this with support for Java 8 language APIs and library desugaring across all API levels.

With the help of desugaring, you can now use Java 8 features like lambda expressions, method references, and the Stream API even if your app‘s minimum SDK version doesn‘t support them natively. The desugaring process converts Java 8 bytecode into equivalent code that can run on older Android versions, so you get the benefits of a modern language without sacrificing compatibility.

To enable Java 8 desugaring, simply include the following in your app‘s build.gradle file:

android {
    ...
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
        coreLibraryDesugaringEnabled true
    }
}

dependencies {
    coreLibraryDesugaring ‘com.android.tools:desugar_jdk_libs:1.0.9‘
}

With these options configured, you‘re good to go with Java 8 features from API level 14 and up. The desugaring process happens transparently at compile time, so there‘s no extra overhead or compatibility concerns to worry about.

Enable/Disable Build Features

The Android Gradle plugin includes a number of optional build features that can be enabled or disabled on a per-module basis. Android Studio 4.0 makes it easy to configure these feature flags in your build.gradle file.

android {
    ...
    buildFeatures {
        dataBinding = true
        viewBinding = true
    }
}

In this example, we‘re enabling both data binding and view binding for the module. If your module doesn‘t use a particular feature, disabling it can speed up your build times and reduce the method count of your app.

The Build Analyzer will even suggest disabling unused build features as an optimization. It‘s a simple but effective way to keep your build streamlined and performant.

Improved R8 Rules Editing

The R8 code shrinker, which is now enabled by default, helps reduce the size of your app‘s DEX files and improve performance. However, configuring the rules for R8 can sometimes be tricky. Android Studio 4.0 makes it easier with a new, smarter code editor for R8 rules.

The updated editor provides syntax highlighting, auto-completion, and error checking as you type, making it simpler to define the right rules for your app. It also offers full symbol completion for all of your project‘s classes and methods, as well as refactoring and navigation support.

Here‘s an example R8 rule that tells the shrinker to keep a particular class and all of its members:

-keep class com.example.MyClass {
    *;
}

With the improved R8 rules editing experience in Android Studio 4.0, configuring rules like this is quicker and less error-prone. The editor‘s built-in smarts help you get the most out of R8 without the frustration of debugging obscure configuration issues.

Fragment Templates and Wizards

Fragments are a fundamental building block for modular, reusable UI components in Android. Android Studio 4.0 introduces new templates and wizards to simplify the process of creating and integrating fragments into your app.

The New Fragment wizard, accessible from the New menu in the Navigation Editor, guides you through the process of creating a fragment, including options for generating a layout file, factory methods, and interaction listeners. You can also choose to create a fragment that integrates with the Navigation component, making it easy to slot the fragment into your app‘s navigation flow.

In addition to the basic fragment template, Android Studio 4.0 also includes templates for common fragment patterns like lists, masters/detail views, and settings screens. These templates provide a productive starting point for implementing conventional UI components, complete with best practices for architecture and user interaction.

Kotlin Live Templates

For teams working with Kotlin, Android Studio 4.0 brings a new set of live templates tailored specifically for Android development. Live templates are code snippets that you can quickly insert and parametrize using a keyboard shortcut and auto-completion.

For example, typing newInstance and pressing the Tab key will auto-expand into a full factory method for creating a new instance of a fragment with arguments:

companion object {
    fun newInstance(arg1: String, arg2: String): MyFragment =
            MyFragment().apply {
                arguments = Bundle().apply {
                    putString(ARG1, arg1)
                    putString(ARG2, arg2)
                }
            }
}

The Kotlin live templates in Android Studio 4.0 cover a range of common patterns like creating an Intent, checking the SDK version, finding views by ID, and more. They‘re a handy shortcut for quickly stubbing out everyday boilerplate code, letting you focus on the unique parts of your app.

CPU Profiler UI Enhancements

Performance is a critical aspect of delivering a great user experience, and the CPU Profiler is an indispensable tool for tracking down performance bottlenecks. Android Studio 4.0 introduces several UI enhancements that make performance profiling easier and more productive.

The updated trace view now allows you to group and organize method traces by thread, making it simpler to navigate complex call stacks and isolate performance issues. You can also zoom in on specific portions of the trace timeline for more granular analysis.

The thread activity timeline includes a new "Wall clock time" view that shows you the actual elapsed time for each method call, in addition to the CPU time. This can help identify periods where your app‘s threads are blocked or waiting on I/O, which can point to opportunities for optimization.

The improved CPU Profiler UI also introduces more intuitive touch controls for scrolling and zooming, as well as better visual separation between app and system threads. All of these enhancements add up to a more streamlined workflow for diagnosing and fixing performance problems.

Feature-on-Feature Dependencies

Dynamic feature modules are a powerful tool for building modular, on-demand app experiences. However, configuring dependencies between different feature modules has historically been cumbersome. Android Studio 4.0 simplifies this with built-in support for feature-on-feature dependencies.

With this new feature, you can easily specify that one dynamic feature module depends on another, ensuring that the dependent module is automatically included when the parent module is downloaded and installed.

Here‘s an example of how to declare a feature-on-feature dependency in a dynamic feature module‘s build.gradle file:

android {
    ...
    dynamicFeatures = [":parent_dynamic_feature"]
}

By listing the parent dynamic feature in the dynamicFeatures property, we‘re telling the build system that this module depends on :parent_dynamic_feature and should be included whenever the parent is installed on a device.

Feature-on-feature dependencies are a simpler alternative to manually tracking and bundling dependent modules. They help ensure your modular app is always in a consistent state, with all the necessary components available on demand.

Conclusion

Android Studio 4.0 is a massive release, packed with productivity enhancements for every stage of the app development process. From design to debugging, testing to optimization, there‘s something for every Android developer to get excited about.

The new Motion Editor and Layout Inspector provide powerful tools for crafting pixel-perfect UIs with ease. Java 8 language feature support and Kotlin live templates help you write more expressive, maintainable code. And with the Build Analyzer and feature-on-feature dependency support, it‘s never been easier to optimize your app‘s performance and modularity.

While this article covers many of the highlights, there are plenty of additional gems to discover in Android Studio 4.0. Whether you‘re a seasoned pro or just starting out, I highly recommend taking it for a spin and seeing how it can level up your Android development workflow.

The future of Android development is looking brighter than ever, and Android Studio 4.0 is leading the charge. I can‘t wait to see the amazing apps and experiences that developers will create with these new tools and capabilities at their disposal. Happy coding!