SaveInstance on screen rotation

app/src/main/java/chat/rocket/android/app/DateTimeHelper.kt

@@ -17,8 +17,8 @@ object DateTimeHelper {
      * @param long The [Long]
      * @return The [LocalDateTime] from a [Long].
      */
-    fun getLocalDateTime(long: Long): LocalDateTime {
-        return LocalDateTime.ofInstant(Instant.ofEpochMilli(long), ZoneId.systemDefault())
+    fun getLocalDateTime(long: Long?): LocalDateTime {
+        return LocalDateTime.ofInstant(long?.let { Instant.ofEpochMilli(it) }, ZoneId.systemDefault())
     }
 
     /**

app/src/main/java/chat/rocket/android/main/ui/MainActivity.kt

@@ -52,6 +52,7 @@ class MainActivity : AppCompatActivity(), MainView, HasActivityInjector, HasSupp
     private var expanded = false
     private lateinit var googleApiClient: GoogleApiClient
     private val headerLayout by lazy { view_navigation.getHeaderView(0) }
+    private val CURRENT_STATE = "current_state"
 
     override fun onCreate(savedInstanceState: Bundle?) {
         AndroidInjection.inject(this)
@@ -268,4 +269,14 @@ class MainActivity : AppCompatActivity(), MainView, HasActivityInjector, HasSupp
             }
         }
     }
+
+    override fun onSaveInstanceState(outState: Bundle?) {
+        super.onSaveInstanceState(outState)
+        outState?.putBoolean(CURRENT_STATE,isFragmentAdded)
+    }
+
+    override fun onRestoreInstanceState(savedInstanceState: Bundle?) {
+        super.onRestoreInstanceState(savedInstanceState)
+        isFragmentAdded = savedInstanceState?.getBoolean(CURRENT_STATE) ?: false
+    }
 }
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