fix undead MainActivity appearing after browser login and back press (#5056)

To reproduce, login an additional account via Browser login and then
press back. You will find yourself in a broken interface where the
displayed posts don't match the logged-in account. This does not happen
with Tusky login.
Seems like `finishAffinity()` does not work as expected when there is an
Activity of another app (the browser) on the stack.
Fix with the nuclear option (starting a new task). Also remove the
explode animation, as this was broken before (finish needs to be called
after startActivity for the animation to appear) and animations between
tasks don't work in newer Android versions anyway.

app/src/main/java/com/keylesspalace/tusky/MainActivity.kt

@@ -95,11 +95,9 @@ import com.keylesspalace.tusky.pager.MainPagerAdapter
 import com.keylesspalace.tusky.settings.PrefKeys
 import com.keylesspalace.tusky.usecase.DeveloperToolsUseCase
 import com.keylesspalace.tusky.usecase.LogoutUsecase
-import com.keylesspalace.tusky.util.ActivityConstants
 import com.keylesspalace.tusky.util.emojify
 import com.keylesspalace.tusky.util.getParcelableExtraCompat
 import com.keylesspalace.tusky.util.hide
-import com.keylesspalace.tusky.util.overrideActivityTransitionCompat
 import com.keylesspalace.tusky.util.reduceSwipeSensitivity
 import com.keylesspalace.tusky.util.show
 import com.keylesspalace.tusky.util.startActivityWithSlideInAnimation
@@ -217,14 +215,6 @@ class MainActivity : BottomSheetActivity(), ActionButtonActivity, MenuProvider {
             viewModel.setupNotifications(this)
         }
 
-        if (explodeAnimationWasRequested()) {
-            overrideActivityTransitionCompat(
-                ActivityConstants.OVERRIDE_TRANSITION_OPEN,
-                R.anim.explode,
-                R.anim.activity_open_exit
-            )
-        }
-
         selectedEmojiPack = preferences.getString(EMOJI_PREFERENCE, "")
 
         var showNotificationTab = false
@@ -1118,15 +1108,9 @@ class MainActivity : BottomSheetActivity(), ActionButtonActivity, MenuProvider {
         }
     }
 
-    private fun explodeAnimationWasRequested(): Boolean {
-        return intent.getBooleanExtra(OPEN_WITH_EXPLODE_ANIMATION, false)
-    }
-
     override fun getActionButton() = binding.composeButton
 
     companion object {
-        const val OPEN_WITH_EXPLODE_ANIMATION = "explode"
-
         private const val TAG = "MainActivity" // logging tag
         private const val DRAWER_ITEM_ADD_ACCOUNT: Long = -13
         private const val DRAWER_ITEM_ANNOUNCEMENTS: Long = 14

app/src/main/java/com/keylesspalace/tusky/components/login/LoginActivity.kt

@@ -291,9 +291,8 @@ class LoginActivity : BaseActivity() {
                 oauthScopes = OAUTH_SCOPES,
                 newAccount = newAccount
             )
-            finishAffinity()
             val intent = Intent(this, MainActivity::class.java)
-            intent.putExtra(MainActivity.OPEN_WITH_EXPLODE_ANIMATION, true)
+            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK)
             startActivity(intent)
         }, { e ->
             setLoading(false)

app/src/main/res/anim/explode.xml

@@ -1,12 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<set xmlns:android="http://schemas.android.com/apk/res/android"  >
-    <scale
-        android:duration="300"
-        android:fromXScale="0"
-        android:fromYScale="0"
-        android:pivotX="50%"
-        android:pivotY="50%"
-        android:toXScale="1"
-        android:toYScale="1" >
-    </scale>
-</set>