Abstract: Learn how to identify and fix memory leaks in Compose apps using LeakCanary, Snapshot State Observer, and NavBackStackEntry.
2024-04-28 by DevCodeF1 Editors
Identifying Leaks with LeakCanary in a Compose Navigation Component App
LeakCanary is a powerful memory leak detection library for Android that helps developers identify and fix memory leaks in their applications. Memory leaks can be a significant problem in Android development, causing performance issues, increased battery usage, and a poor user experience. In this article, we will explore how to use LeakCanary to identify leaks in a Compose Navigation Component app, specifically when changing the phone's mode between light and dark themes.
What is a Memory Leak?
A memory leak occurs when an application holds a reference to an object that is no longer needed. This prevents the object from being garbage collected, causing it to take up memory unnecessarily. Over time, this can lead to performance issues and a poor user experience. In Android, memory leaks can be particularly problematic due to the limited amount of memory available on mobile devices.
What is LeakCanary?
LeakCanary is an open-source memory leak detection library for Android developed by Square. It helps developers identify memory leaks in their applications by monitoring the heap and reporting any leaks it finds. LeakCanary is easy to use and integrates seamlessly with most Android projects.
Identifying Leaks in a Compose Navigation Component App
To identify leaks in a Compose Navigation Component app, we will use LeakCanary to monitor the heap and report any leaks it finds. In this example, we are interested in identifying leaks that occur when changing the phone's mode between light and dark themes. To do this, we will follow these steps:
- Add LeakCanary to the project
- Configure LeakCanary to monitor the heap
- Reproduce the leak by changing the phone's mode between light and dark themes
- Analyze the leak report generated by LeakCanary
Adding LeakCanary to the Project
To add LeakCanary to the project, we need to add the following dependencies to the app-level build.gradle file:
dependencies {debugImplementation 'com.squareup.leakcanary:leakcanary-android:2.8'releaseImplementation 'com.squareup.leakcanary:leakcanary-android-no-op:2.8'}
These dependencies add LeakCanary to the project and ensure that it is only active in debug builds. This is important to prevent LeakCanary from affecting the performance of the release build.
Configuring LeakCanary to Monitor the Heap
To configure LeakCanary to monitor the heap, we need to create a LeakCanary object and initialize it in the application's onCreate() method. We can do this by adding the following code to the MainApplication.kt file:
import androidx.startup.AppInitializerimport com.squareup.leakcanary.LeakCanaryclass MainApplication : Application() {override fun onCreate() {super.onCreate()if (LeakCanary.isInAnalyzerProcess(this)) {return}LeakCanary.install(this)AppInitializer.getInstance(this).initializeComponent()}
This code creates a LeakCanary object and initializes it in the application's onCreate() method. It also checks if the process is an analyzer process and returns if it is. This is important to prevent LeakCanary from analyzing its own memory usage.
Reproducing the Leak
To reproduce the leak, we need to change the phone's mode between light and dark themes. We can do this by using the Compose Navigation component and navigating between two screens with different themes. To do this, we can add the following code to the Navigation.kt file:
import androidx.compose.foundation.layout.fillMaxSizeimport androidx.compose.material.MaterialThemeimport androidx.compose.material.Surfaceimport androidx.compose.material.darkColorsimport androidx.compose.material.lightColorsimport androidx.compose.runtime.Composableimport androidx.compose.ui.Modifierprivate val DarkColorPalette = darkColors(primary = Color.Black,secondary = Color.Magenta)private val LightColorPalette = lightColors(primary = Color.White,secondary = Color.Yellow)@Composablefun Screen1(navController: NavController) {val colors = DarkColorPaletteSurface(modifier = Modifier.fillMaxSize(),color = MaterialTheme.colors.background) {ScreenContent(navController, colors)}}@Composablefun Screen2(navController: NavController) {val colors = LightColorPaletteSurface(modifier = Modifier.fillMaxSize(),color = MaterialTheme.colors.background) {ScreenContent(navController, colors)}}@Composablefun ScreenContent(navController: NavController, colors: Colors) {// Content for the screen}
This code defines two screens with different themes. The first screen uses a dark theme, and the second screen uses a light theme. We can navigate between these screens using the Navigation component. To reproduce the leak, we need to navigate between these screens multiple times and then use LeakCanary to analyze the heap.
Analyzing the Leak
To analyze the leak, we need to use LeakCanary to generate a heap dump and analyze it. We can do this by triggering a memory leak and then using the LeakCanary UI to analyze the heap. To trigger a memory leak, we can use the following code:
import androidx.appcompat.app.AppCompatActivityimport android.os.Bundleimport com.squareup.leakcanary.LeakCanaryclass MainActivity : AppCompatActivity() {override fun onCreate(savedInstanceState: Bundle?) {super.onCreate(savedInstanceState)setContentView(R.layout.activity\_main)LeakCanary.refWatcher.watch(this)}
This code watches the MainActivity object for leaks. To generate a heap dump, we can use the LeakCanary UI. This will generate a heap dump and analyze it for leaks. If a leak is found, LeakCanary will display a detailed report showing the object that was leaked and the stack trace that caused the leak.
In this article, we have explored how to use LeakCanary to identify memory leaks in a Compose Navigation Component app. We have covered what a memory leak is, what LeakCanary is, and how to add it to a project. We have also explored how to configure LeakCanary to monitor the heap, reproduce a leak, and analyze the leak report. By following these steps, we can identify and fix memory leaks in our Compose Navigation Component apps, ensuring a smooth and performant user experience.
