Fix multi Activity wen opening app from notification.

app/src/main/AndroidManifest.xml

@@ -1,5 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
-<!--
+<?xml version="1.0" encoding="utf-8"?><!--
   ~ Copyright (c) 2022 New Vector Ltd
   ~
   ~ Licensed under the Apache License, Version 2.0 (the "License");
@@ -31,9 +30,10 @@
         tools:targetApi="33">
         <activity
             android:name=".MainActivity"
-            android:theme="@style/Theme.ElementX.Splash"
             android:configChanges="orientation|screenSize|screenLayout|keyboardHidden|uiMode"
             android:exported="true"
+            android:launchMode="singleInstance"
+            android:theme="@style/Theme.ElementX.Splash"
             android:windowSoftInputMode="adjustResize">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />

app/src/main/kotlin/io/element/android/x/MainActivity.kt

@@ -16,6 +16,7 @@
 
 package io.element.android.x
 
+import android.content.Intent
 import android.os.Bundle
 import androidx.activity.compose.setContent
 import androidx.compose.foundation.background
@@ -30,6 +31,7 @@ import com.bumble.appyx.core.integrationpoint.NodeComponentActivity
 import io.element.android.libraries.architecture.bindings
 import io.element.android.libraries.designsystem.theme.ElementTheme
 import io.element.android.x.di.AppBindings
+import timber.log.Timber
 
 class MainActivity : NodeComponentActivity() {
 
@@ -52,6 +54,17 @@ class MainActivity : NodeComponentActivity() {
         }
     }
 
+    /**
+     * Called when:
+     * - the launcher icon is clicked (if the app is already running);
+     * - a notification is clicked.
+     * - the app is going to background (<- this is strange)
+     */
+    override fun onNewIntent(intent: Intent?) {
+        super.onNewIntent(intent)
+        Timber.w("onNewIntent")
+    }
+
     override fun onSaveInstanceState(outState: Bundle) {
         super.onSaveInstanceState(outState)
         bindings<AppBindings>().matrixClientsHolder().onSaveInstanceState(outState)