Fix #5451 : java.lang.IllegalStateException - Media player has not been previously initialized

domain/src/main/java/org/oppia/android/domain/audio/AudioPlayerController.kt

@@ -251,13 +251,15 @@ class AudioPlayerController @Inject constructor(
    */
   fun releaseMediaPlayer() {
     audioLock.withLock {
-      check(mediaPlayerActive) { "Media player has not been previously initialized" }
-      mediaPlayerActive = false
-      isReleased = true
-      prepared = false
-      mediaPlayer.release()
-      stopUpdatingSeekBar()
-      playProgress = null
+      if (!isReleased) {
+        check(mediaPlayerActive) { "Media player has not been previously initialized" }
+        mediaPlayerActive = false
+        isReleased = true
+        prepared = false
+        mediaPlayer.release()
+        stopUpdatingSeekBar()
+        playProgress = null
+      }
     }
   }
 

domain/src/test/java/org/oppia/android/domain/audio/AudioPlayerControllerTest.kt

@@ -11,6 +11,7 @@ import dagger.BindsInstance
 import dagger.Component
 import dagger.Module
 import dagger.Provides
+import org.junit.Assert.fail
 import org.junit.Rule
 import org.junit.Test
 import org.junit.runner.RunWith
@@ -443,6 +444,17 @@ class AudioPlayerControllerTest {
       .contains("Media player has not been previously initialized")
   }
 
+  @Test
+  fun testController_releasePlayerMultipleTimes_doesNoThrowException() {
+    setUpMediaReadyApplication()
+    audioPlayerController.initializeMediaPlayer()
+
+    assertNoExceptionIsThrown {
+      audioPlayerController.releaseMediaPlayer()
+      audioPlayerController.releaseMediaPlayer()
+    }
+  }
+
   @Test
   fun testError_notPrepared_invokePlay_fails() {
     setUpMediaReadyApplication()
@@ -872,6 +884,14 @@ class AudioPlayerControllerTest {
     ApplicationProvider.getApplicationContext<TestApplication>().inject(this)
   }
 
+  private fun assertNoExceptionIsThrown(block: () -> Unit) {
+    try {
+      block()
+    } catch (e: Exception) {
+      fail("Expected no exception, but got: $e")
+    }
+  }
+
   // TODO(#89): Move this to a common test application component.
   @Module
   class TestModule {