I followed rule of 3.

depconstraints/build.gradle.kts

@@ -55,7 +55,7 @@ val hamcrest = "1.3"
 val hilt = Versions.HILT_AGP
 val junit = "4.13"
 val junitExt = "1.1.1"
-val lifecycle = "2.4.0-alpha01"
+val lifecycle = "2.4.1"
 val lottie = "3.0.0"
 val material = "1.4.0-beta01"
 val mockito = "3.3.1"

mobile/src/main/java/com/google/samples/apps/iosched/ui/LauncherActivity.kt

@@ -26,8 +26,8 @@ import androidx.lifecycle.repeatOnLifecycle
 import com.google.samples.apps.iosched.ui.LaunchNavigatonAction.NavigateToMainActivityAction
 import com.google.samples.apps.iosched.ui.LaunchNavigatonAction.NavigateToOnboardingAction
 import com.google.samples.apps.iosched.ui.onboarding.OnboardingActivity
+import com.google.samples.apps.iosched.util.collectLifecycleFlow
 import dagger.hilt.android.AndroidEntryPoint
-import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.launch
 
 /**
@@ -41,20 +41,16 @@ class LauncherActivity : AppCompatActivity() {
 
         val viewModel: LaunchViewModel by viewModels()
 
-        lifecycleScope.launch {
-            lifecycle.repeatOnLifecycle(Lifecycle.State.STARTED) {
-                viewModel.launchDestination.collect { action ->
-                    when (action) {
-                        is NavigateToMainActivityAction -> startActivity(
-                            Intent(this@LauncherActivity, MainActivity::class.java)
-                        )
-                        is NavigateToOnboardingAction -> startActivity(
-                            Intent(this@LauncherActivity, OnboardingActivity::class.java)
-                        )
-                    }
-                    finish()
-                }
+        collectLifecycleFlow(viewModel.launchDestination) { action ->
+            when (action) {
+                is NavigateToMainActivityAction -> startActivity(
+                    Intent(this@LauncherActivity, MainActivity::class.java)
+                )
+                is NavigateToOnboardingAction -> startActivity(
+                    Intent(this@LauncherActivity, OnboardingActivity::class.java)
+                )
             }
+            finish()
         }
     }
 }

mobile/src/main/java/com/google/samples/apps/iosched/ui/MainActivity.kt

@@ -30,9 +30,6 @@ import androidx.core.view.WindowCompat
 import androidx.core.view.WindowInsetsCompat
 import androidx.core.view.isVisible
 import androidx.core.view.updatePadding
-import androidx.lifecycle.Lifecycle
-import androidx.lifecycle.lifecycleScope
-import androidx.lifecycle.repeatOnLifecycle
 import androidx.navigation.NavController
 import androidx.navigation.fragment.NavHostFragment
 import androidx.navigation.ui.AppBarConfiguration
@@ -52,11 +49,10 @@ import com.google.samples.apps.iosched.ui.messages.SnackbarMessageManager
 import com.google.samples.apps.iosched.ui.signin.SignInDialogFragment
 import com.google.samples.apps.iosched.ui.signin.SignOutDialogFragment
 import com.google.samples.apps.iosched.util.HeightTopWindowInsetsListener
+import com.google.samples.apps.iosched.util.collectLifecycleFlow
 import com.google.samples.apps.iosched.util.signin.FirebaseAuthErrorCodeConverter
 import com.google.samples.apps.iosched.util.updateForTheme
 import dagger.hilt.android.AndroidEntryPoint
-import kotlinx.coroutines.flow.collect
-import kotlinx.coroutines.launch
 import timber.log.Timber
 import java.util.UUID
 import javax.inject.Inject
@@ -155,36 +151,20 @@ class MainActivity : AppCompatActivity(), NavigationHost {
             navigateTo(requestedNavId)
         }
 
-        lifecycleScope.launch {
-            lifecycle.repeatOnLifecycle(Lifecycle.State.STARTED) {
-                launch {
-                    viewModel.navigationActions.collect { action ->
-                        when (action) {
-                            MainNavigationAction.OpenSignIn -> openSignInDialog()
-                            MainNavigationAction.OpenSignOut -> openSignOutDialog()
-                        }
-                    }
-                }
-                launch {
-                    viewModel.theme.collect { theme ->
-                        updateForTheme(theme)
-                    }
-                }
-                // AR-related Flows
-                launch {
-                    viewModel.arCoreAvailability.collect { result ->
-                        // Do nothing - activate flow
-                        Timber.d("ArCoreAvailability = $result")
-                    }
-                }
-                launch {
-                    viewModel.pinnedSessionsJson.collect { /* Do nothing - activate flow */ }
-                }
-                launch {
-                    viewModel.canSignedInUserDemoAr.collect { /* Do nothing - activate flow  */ }
-                }
+        collectLifecycleFlow(viewModel.navigationActions) { action ->
+            when (action) {
+                MainNavigationAction.OpenSignIn -> openSignInDialog()
+                MainNavigationAction.OpenSignOut -> openSignOutDialog()
             }
         }
+        collectLifecycleFlow(viewModel.navigationActions) { /* Do nothing - activate flow */}
+        collectLifecycleFlow(viewModel.theme) { /* Do nothing - activate flow */ }
+        collectLifecycleFlow(viewModel.arCoreAvailability) { result ->
+            // Do nothing - activate flow
+            Timber.d("ArCoreAvailability = $result")
+        }
+        collectLifecycleFlow(viewModel.pinnedSessionsJson) { /* Do nothing - activate flow */ }
+        collectLifecycleFlow(viewModel.canSignedInUserDemoAr) { /* Do nothing - activate flow */ }
 
         binding.navigationRail?.let {
             ViewCompat.setOnApplyWindowInsetsListener(it) { view, insets ->

mobile/src/main/java/com/google/samples/apps/iosched/ui/map/MapVariantSelectionDialogFragment.kt

@@ -32,6 +32,7 @@ import androidx.lifecycle.lifecycleScope
 import androidx.lifecycle.repeatOnLifecycle
 import androidx.recyclerview.widget.RecyclerView
 import com.google.samples.apps.iosched.R
+import com.google.samples.apps.iosched.util.collectLifecycleFlow
 import dagger.hilt.android.AndroidEntryPoint
 import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.launch
@@ -61,12 +62,8 @@ class MapVariantSelectionDialogFragment : AppCompatDialogFragment() {
         adapter = MapVariantAdapter(::selectMapVariant)
         view.findViewById<RecyclerView>(R.id.map_variant_list).adapter = adapter
 
-        lifecycleScope.launch {
-            lifecycle.repeatOnLifecycle(Lifecycle.State.STARTED) {
-                mapViewModel.mapVariant.collect {
-                    adapter.currentSelection = it
-                }
-            }
+        collectLifecycleFlow(mapViewModel.mapVariant) {
+            adapter.currentSelection = it
         }
     }
 

mobile/src/main/java/com/google/samples/apps/iosched/ui/onboarding/OnboardingActivity.kt

@@ -23,16 +23,12 @@ import androidx.appcompat.app.AppCompatActivity
 import androidx.core.view.WindowCompat
 import androidx.core.view.WindowInsetsCompat
 import androidx.core.view.updatePadding
-import androidx.lifecycle.Lifecycle
-import androidx.lifecycle.lifecycleScope
-import androidx.lifecycle.repeatOnLifecycle
 import com.google.samples.apps.iosched.R
 import com.google.samples.apps.iosched.shared.util.inTransaction
 import com.google.samples.apps.iosched.ui.signin.SignInDialogFragment
+import com.google.samples.apps.iosched.util.collectLifecycleFlow
 import com.google.samples.apps.iosched.util.doOnApplyWindowInsets
 import dagger.hilt.android.AndroidEntryPoint
-import kotlinx.coroutines.flow.collect
-import kotlinx.coroutines.launch
 
 @AndroidEntryPoint
 class OnboardingActivity : AppCompatActivity() {
@@ -57,13 +53,9 @@ class OnboardingActivity : AppCompatActivity() {
             }
         }
 
-        lifecycleScope.launch {
-            lifecycle.repeatOnLifecycle(Lifecycle.State.STARTED) {
-                viewModel.navigationActions.collect { action ->
-                    if (action == OnboardingNavigationAction.NavigateToSignInDialog) {
-                        openSignInDialog()
-                    }
-                }
+        collectLifecycleFlow(viewModel.navigationActions) { action ->
+            if (action == OnboardingNavigationAction.NavigateToSignInDialog) {
+                openSignInDialog()
             }
         }
     }

mobile/src/main/java/com/google/samples/apps/iosched/ui/reservation/RemoveReservationDialogFragment.kt

@@ -31,6 +31,7 @@ import androidx.lifecycle.repeatOnLifecycle
 import com.google.android.material.dialog.MaterialAlertDialogBuilder
 import com.google.samples.apps.iosched.R
 import com.google.samples.apps.iosched.model.SessionId
+import com.google.samples.apps.iosched.util.collectLifecycleFlow
 import com.google.samples.apps.iosched.util.makeBold
 import dagger.hilt.android.AndroidEntryPoint
 import kotlinx.coroutines.flow.collect
@@ -92,17 +93,13 @@ class RemoveReservationDialogFragment : AppCompatDialogFragment() {
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
 
-        lifecycleScope.launch {
-            lifecycle.repeatOnLifecycle(Lifecycle.State.STARTED) {
-                viewModel.snackbarMessages.collect {
-                    // Using Toast instead of Snackbar as it's easier for DialogFragment
-                    Toast.makeText(
-                        requireContext(),
-                        it.messageId,
-                        if (it.longDuration) Toast.LENGTH_LONG else Toast.LENGTH_SHORT
-                    ).show()
-                }
-            }
+        collectLifecycleFlow(viewModel.snackbarMessages) {
+            // Using Toast instead of Snackbar as it's easier for DialogFragment
+            Toast.makeText(
+                requireContext(),
+                it.messageId,
+                if (it.longDuration) Toast.LENGTH_LONG else Toast.LENGTH_SHORT
+            ).show()
         }
     }
 

mobile/src/main/java/com/google/samples/apps/iosched/ui/settings/ThemeSettingDialogFragment.kt

@@ -22,15 +22,11 @@ import android.widget.ArrayAdapter
 import androidx.appcompat.app.AlertDialog
 import androidx.appcompat.app.AppCompatDialogFragment
 import androidx.fragment.app.viewModels
-import androidx.lifecycle.Lifecycle
-import androidx.lifecycle.lifecycleScope
-import androidx.lifecycle.repeatOnLifecycle
 import com.google.android.material.dialog.MaterialAlertDialogBuilder
 import com.google.samples.apps.iosched.R
 import com.google.samples.apps.iosched.model.Theme
+import com.google.samples.apps.iosched.util.collectLifecycleFlow
 import dagger.hilt.android.AndroidEntryPoint
-import kotlinx.coroutines.flow.collect
-import kotlinx.coroutines.launch
 
 @AndroidEntryPoint
 class ThemeSettingDialogFragment : AppCompatDialogFragment() {
@@ -61,26 +57,17 @@ class ThemeSettingDialogFragment : AppCompatDialogFragment() {
         super.onCreate(savedInstanceState)
 
         // Note you don't need to use viewLifecycleOwner in DialogFragment.
-        lifecycleScope.launch {
-            lifecycle.repeatOnLifecycle(Lifecycle.State.STARTED) {
-                viewModel.availableThemes.collect { themes ->
-                    listAdapter.clear()
-                    listAdapter.addAll(
-                        themes.map { theme ->
-                            ThemeHolder(theme, getTitleForTheme(theme))
-                        }
-                    )
-
-                    updateSelectedItem(viewModel.theme.value)
+        collectLifecycleFlow(viewModel.availableThemes) { themes ->
+            listAdapter.clear()
+            listAdapter.addAll(
+                themes.map { theme ->
+                    ThemeHolder(theme, getTitleForTheme(theme))
                 }
-            }
+            )
+            updateSelectedItem(viewModel.theme.value)
         }
 
-        lifecycleScope.launch {
-            lifecycle.repeatOnLifecycle(Lifecycle.State.STARTED) {
-                viewModel.theme.collect { updateSelectedItem(it) }
-            }
-        }
+        collectLifecycleFlow(viewModel.theme) { updateSelectedItem(it) }
     }
 
     private fun updateSelectedItem(selected: Theme?) {

mobile/src/main/java/com/google/samples/apps/iosched/ui/signin/SignInDialogFragment.kt

@@ -30,6 +30,7 @@ import androidx.lifecycle.repeatOnLifecycle
 import com.google.android.material.dialog.MaterialAlertDialogBuilder
 import com.google.samples.apps.iosched.databinding.DialogSignInBinding
 import com.google.samples.apps.iosched.ui.signin.SignInNavigationAction.RequestSignIn
+import com.google.samples.apps.iosched.util.collectLifecycleFlow
 import com.google.samples.apps.iosched.util.executeAfter
 import com.google.samples.apps.iosched.util.signin.SignInHandler
 import dagger.hilt.android.AndroidEntryPoint
@@ -69,17 +70,14 @@ class SignInDialogFragment : AppCompatDialogFragment() {
     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
         super.onViewCreated(view, savedInstanceState)
 
-        lifecycleScope.launch {
-            lifecycle.repeatOnLifecycle(Lifecycle.State.STARTED) {
-                signInViewModel.signInNavigationActions.collect { action ->
-                    if (action == RequestSignIn) {
-                        activity?.startActivityForResult(
-                            signInHandler.makeSignInIntent(),
-                            REQUEST_CODE_SIGN_IN
-                        )
-                        dismiss()
-                    }
-                }
+        collectLifecycleFlow(signInViewModel.signInNavigationActions) {
+                action ->
+            if (action == RequestSignIn) {
+                activity?.startActivityForResult(
+                    signInHandler.makeSignInIntent(),
+                    REQUEST_CODE_SIGN_IN
+                )
+                dismiss()
             }
         }
 

mobile/src/main/java/com/google/samples/apps/iosched/ui/signin/SignOutDialogFragment.kt

@@ -34,6 +34,7 @@ import com.google.android.material.dialog.MaterialAlertDialogBuilder
 import com.google.samples.apps.iosched.databinding.DialogSignOutBinding
 import com.google.samples.apps.iosched.shared.data.signin.AuthenticatedUserInfo
 import com.google.samples.apps.iosched.ui.signin.SignInNavigationAction.RequestSignOut
+import com.google.samples.apps.iosched.util.collectLifecycleFlow
 import com.google.samples.apps.iosched.util.executeAfter
 import com.google.samples.apps.iosched.util.signin.SignInHandler
 import dagger.hilt.android.AndroidEntryPoint
@@ -73,14 +74,10 @@ class SignOutDialogFragment : AppCompatDialogFragment() {
     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
         super.onViewCreated(view, savedInstanceState)
 
-        lifecycleScope.launch {
-            lifecycle.repeatOnLifecycle(Lifecycle.State.STARTED) {
-                signInViewModel.signInNavigationActions.collect { action ->
-                    if (action == RequestSignOut) {
-                        signInHandler.signOut(requireContext())
-                        dismiss()
-                    }
-                }
+        collectLifecycleFlow(signInViewModel.signInNavigationActions) { action ->
+            if (action == RequestSignOut) {
+                signInHandler.signOut(requireContext())
+                dismiss()
             }
         }
 

mobile/src/main/java/com/google/samples/apps/iosched/util/Extensions.kt

@@ -23,12 +23,8 @@ import android.content.res.TypedArray
 import android.graphics.Typeface
 import android.net.wifi.WifiConfiguration
 import android.os.Build
+import android.text.*
 import android.text.Layout.Alignment
-import android.text.Spannable
-import android.text.SpannableString
-import android.text.Spanned
-import android.text.StaticLayout
-import android.text.TextPaint
 import android.text.style.StyleSpan
 import android.util.TypedValue
 import android.view.View
@@ -37,16 +33,21 @@ import androidx.annotation.ColorInt
 import androidx.annotation.DimenRes
 import androidx.appcompat.app.AppCompatActivity
 import androidx.appcompat.app.AppCompatDelegate
+import androidx.appcompat.app.AppCompatDialogFragment
 import androidx.core.content.res.ResourcesCompat
 import androidx.core.os.BuildCompat
 import androidx.core.view.ViewCompat
 import androidx.core.view.WindowInsetsCompat
 import androidx.databinding.ObservableBoolean
 import androidx.databinding.ViewDataBinding
 import androidx.drawerlayout.widget.DrawerLayout
-import androidx.lifecycle.LiveData
-import androidx.lifecycle.MediatorLiveData
+import androidx.fragment.app.Fragment
+import androidx.lifecycle.*
 import com.google.samples.apps.iosched.model.Theme
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.FlowCollector
+import kotlinx.coroutines.flow.collectLatest
+import kotlinx.coroutines.launch
 
 fun ObservableBoolean.hasSameValue(other: ObservableBoolean) = get() == other.get()
 
@@ -326,3 +327,19 @@ fun Context.getColorFromTheme(colorAttributeId: Int): Int {
     typedArray.recycle()
     return color
 }
+/** to collect flow in a life cycle scope for [AppCompatActivity] * */
+fun <T> AppCompatActivity.collectLifecycleFlow(flow: Flow<T>, collect: FlowCollector<T>) {
+    lifecycleScope.launch {
+        repeatOnLifecycle(Lifecycle.State.STARTED) {
+            flow.collect(collect)
+        }
+    }
+}
+/** to collect flow in a life cycle scope for [Fragment] * */
+fun <T> Fragment.collectLifecycleFlow(flow: Flow<T>, collect: FlowCollector<T>) {
+    lifecycleScope.launch {
+        lifecycle.repeatOnLifecycle(Lifecycle.State.STARTED) {
+            flow.collect(collect)
+        }
+    }
+}