退出后 Android onCreate 被调用两次

Question

I have a simple MainActivity and if the app is completely killed it looks like onCreate() is called once. If however I back out of the app so it still appears in the background, when I re-open it I get every log message twice. The weirdest part is if I generate a random number it is always the same in the 2 log messages.

I've tried adding android:LaunchMode="singleTop" (also singleInstance singleTask) in the activity and application tags of the Manifest.

class MainActivity : AppCompatActivity() {

private val binding: ActivityMainBinding by lazy {
    ActivityMainBinding.inflate(layoutInflater)
}

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    val view = binding.root
    setContentView(view)
    setupViews()
    val data: Uri? = intent?.data
    DataHolder.getInstance().setItem(data)
    Timber.plant(Timber.DebugTree())
    setupInjection()
    Timber.d("review nanoTime = ${System.nanoTime()}")
    Timber.d("review savedInstance = $savedInstanceState")
    Timber.d("review random = ${Random.nextInt()}")
}

override fun onPause() {
    Timber.d("review onPause()")
    super.onPause()
}

override fun onStop() {
    Timber.d("review onStop()")
    super.onStop()
}

override fun onDestroy() {
    Timber.d("review onDestroy()")
    super.onDestroy()
    finish()
}

override fun onStart() {
    Timber.d("review onStart()")
    super.onStart()
}

override fun onRestart() {
    Timber.d("review onRestart()")
    super.onRestart()
}

override fun onResume() {
    Timber.d("review onResume()")
    super.onResume()
}
private fun setupInjection() {
    val appInjector = InjectorImpl(
        firebaseAuth = FirebaseAuth.getInstance()
    )
    Injector.initialize(appInjector)
}

private fun setupViews() = binding.apply {
    val navController = findNavController(R.id.nav_host_fragment)

    navView.setupWithNavController(navController)
    navView.setOnItemSelectedListener { item ->
        when (item.itemId){
            R.id.navigation_item_calculator -> {
                navController.navigate(BuilderFragmentDirections.actionBuilderToCalculator())
            }
            R.id.navigation_item_builder -> {
                navController.navigate(CalculatorFragmentDirections.actionCalculatorToBuilder())
            }
        }
        true
    }
    navView.setOnItemReselectedListener {  }
}
}

Here is a table of the log trace I get when I run the app on my phone from Android studio. Since the random numbers are the same I feel like this is actually a Logging bug in Android studio and the app isn't actually opened twice.

Answer 1

Realized my problem was with my logging library I used.

Timber was planting a new tree but wasn't uprooting old ones from being backed out so there were 2 instances of them. I fixed by putting a Timber.uprootAll() just before Timber.plant(Timber.DebugTree())