Reattach player to ads loader on resume

When pausing and resuming a playback using an AdsLoader
it is necessary to call setPlayer again. This fixes an
issue where playback was stuck in the buffering state
when pausing and resuming an ad playback in the demo app.

PiperOrigin-RevId: 308582143

demos/main/src/main/java/com/google/android/exoplayer2/demo/PlayerActivity.java

@@ -448,7 +448,7 @@ public class PlayerActivity extends AppCompatActivity
    * otherwise.
    */
   @Nullable
-  private AdsLoader createAdsLoader(Uri adTagUri) {
+  private AdsLoader maybeCreateAdsLoader(Uri adTagUri) {
     // Load the extension source using reflection so the demo app doesn't have to depend on it.
     try {
       Class<?> loaderClass = Class.forName("com.google.android.exoplayer2.ext.ima.ImaAdsLoader");
@@ -593,14 +593,14 @@ public class PlayerActivity extends AppCompatActivity
         releaseAdsLoader();
         loadedAdTagUri = adTagUri;
       }
+      // The ads loader is reused for multiple playbacks, so that ad playback can resume.
       if (adsLoader == null) {
-        // The ads loader is reused for multiple playbacks, so that ad playback can resume.
-        adsLoader = createAdsLoader(adTagUri);
-        if (adsLoader != null) {
-          adsLoader.setPlayer(player);
-        } else {
-          showToast(R.string.ima_not_loaded);
-        }
+        adsLoader = maybeCreateAdsLoader(adTagUri);
+      }
+      if (adsLoader != null) {
+        adsLoader.setPlayer(player);
+      } else {
+        showToast(R.string.ima_not_loaded);
       }
       return adsLoader;
     }