LeakCanary

A memory leak detection library for Android and Kotlin.

“A small leak will sink a great ship.” - Benjamin Franklin

Getting started

Add LeakCanary to your build.gradle:

dependencies {
  debugImplementation 'com.squareup.leakcanary:leakcanary-android:2.0-alpha-1'
}

You're good to go! LeakCanary will automatically show a notification when an activity or fragment memory leak is detected in your debug build.

Note: LeakCanary 2 is in alpha. To set up LeakCanary 1.6, go to the 1.6 Readme.

Presentations

• LeakCanary, then what? Nuking Nasty Memory Leaks
• Memory Leak Hunt, a live investigation.

Recipes

Watching custom objects

class MyService : Service {

  // ...

  override fun onDestroy() {
    super.onDestroy()
    LeakSentry.refWatcher.watch(this)
  }

}

Configuring LeakSentry & LeakCanary

LeakSentry is in charge of detecting memory leaks. Its configuration can be updated at any time by replacing LeakSentry.config:

class DebugExampleApplication : ExampleApplication() {

  override fun onCreate() {
    super.onCreate()
    LeakSentry.config = LeakSentry.config.copy(watchFragmentViews = false)
  }
}

LeakCanary is in charge of taking heap dumps and analyzing them. Its configuration can be updated at any time by replacing LeakCanary.config:

disableLeakCanaryButton.setOnClickListener {
  LeakCanary.config = LeakCanary.config.copy(dumpHeap = false)
}

Counting retained instances in production

In your build.gradle:

dependencies {
  implementation 'com.squareup.leakcanary:leakcanary-sentry:2.0-alpha-1'
}

In your leak reporting code:

val retainedInstanceCount = LeakSentry.refWatcher.retainedKeys.size

Alternate setup with the old perflib heap parser

If you want to try LeakCanary 2.0 features with the battle tested perflib heap parser, use a different dependency:

dependencies {
  // debugImplementation 'com.squareup.leakcanary:leakcanary-android:2.0-alpha-1'
  debugImplementation 'com.squareup.leakcanary:leakcanary-android-perflib:2.0-alpha-1'
}

In your debug Application class:

class DebugExampleApplication : ExampleApplication() {

  override fun onCreate() {
    if (LeakCanary.isInAnalyzerProcess(this)) {
      // This process is dedicated to Perflib for heap analysis.
      // You should not init your app in this process.
      return
    }
    super.onCreate()
  }
}

FAQ

Note: the entries in this FAQ have not been updated for LeakCanary 2 yet.

• Why should I use LeakCanary?
• How does it work?
• How do I fix a memory leak?
• How do I customize LeakCanary to my needs?
• Where can I learn more?
• How do I copy the leak trace?
• Can a leak be caused by the Android SDK?
• How can I dig beyond the leak trace?
• How do disable I LeakCanary in tests?
• How do I fix build errors?
• How many methods does LeakCanary add?
• How do I use the SNAPSHOT version?
• How can I be notified of new releases?
• Who's behind LeakCanary?
• Why is it called LeakCanary?
• Who made the logo?
• Instant Run can trigger invalid leaks
• I know I have a leak. Why doesn't the notification show?

License

Copyright 2015 Square, Inc.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.