mazzouzi

override fun onCleared() {
  repository = null
  super.onCleared()
}

mazzouzi

fun main() {
  val actor = Actor("Will", "Smith", 53) // (1)
  val forName = actor.forName // (2)
  val funFact = actor.getFunFact(forName) // (3)
  println(funFact)
}
 
class Actor(val forName: String, val name: String, val age: Int) {
  
  fun getFunFact(key: String?): String? = funFacts[key] // (3')

mazzouzi

dependencies {
    // debugImplementation because LeakCanary should only run in debug builds.
    debugImplementation 'com.squareup.leakcanary:leakcanary-android:2.9.1'
}

mazzouzi

class DialogUtilLeak private constructor(private val context: Context?) {

    fun showError(title: String?, message: String?) {
        if (context == null || (context as Activity).isFinishing) {
            return
        }

        MaterialAlertDialogBuilder(context)
            .setCancelable(true)
            .setTitle(title)

mazzouzi

class BackgroundSolutionPresenter(val view: BackgroundLeakInterface) {

    private val exceptionHandler = CoroutineExceptionHandler { _, exception ->
        // Log exception error to server
    }
    private val coroutineScope = CoroutineScope(Job() + exceptionHandler)

    fun doSomeIntensiveWork() {
        coroutineScope.launch {
            delay(120000) // simulate intensive work

mazzouzi

class BackgroundLeakPresenter(val view: BackgroundLeakInterface) {

    private val exceptionHandler = CoroutineExceptionHandler { _, exception ->
        // Log exception error to server
    }
    private val coroutineScope = CoroutineScope(Job() + exceptionHandler)
    
    fun doSomeIntensiveWork() {
        coroutineScope.launch {
            delay(120000) // simulate intensive work

mazzouzi

object DialogUtilSolution {

    fun showError(context: Context?, title: String?, message: String?) {
        if (context == null || (context as? Activity?)?.isFinishing == true) {
            return
        }

        MaterialAlertDialogBuilder(context)
            .setCancelable(true)
            .setTitle(title)

mazzouzi

private fun onError(errorMessage: String) {
        /**
         * Here we pass a copy of the context as a parameter to every functions
         * of DialogUtilSolution singleton.
         * Once the function returns, the copy is popped off the stack 
         * -> no memory leak ✅
         
         * Be careful, this code will still leak if the user changes configuration while
         * the dialog is displayed because the dialog is not tied to the Activity's lifecycle upon
         * recreation. Please check "solutionfinal" package for complete solution.

mazzouzi

override fun onStop() {
        super.onStop()
        /**
         * Always unregister to the Android API before the view gets destroyed
         * -> no memory leak ✅
         */
        activity?.unregisterReceiver(localBroadcastReceiver)
}

mazzouzi

abstract class BaseTwoPanelsLeakFragment(
    private val side: Fragment,
    private val main: Fragment
) : Fragment() {

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        childFragmentManager.beginTransaction().apply {
            replace(R.id.side_container, side)
            replace(R.id.main_container, main)