Ensure videos are paused properly in MediaSendActivity.

src/org/thoughtcrime/securesms/mediasend/MediaSendFragment.java

@@ -82,9 +82,17 @@ public class MediaSendFragment extends Fragment {
     super.onHiddenChanged(hidden);
     if (!hidden) {
       viewModel.onImageEditorStarted();
+    } else {
+      fragmentPagerAdapter.notifyHidden();
     }
   }
 
+  @Override
+  public void onPause() {
+    super.onPause();
+    fragmentPagerAdapter.notifyHidden();
+  }
+
   @Override
   public void onStop() {
     super.onStop();
@@ -143,6 +151,7 @@ public class MediaSendFragment extends Fragment {
     @Override
     public void onPageSelected(int position) {
       viewModel.onPageChanged(position);
+      fragmentPagerAdapter.notifyPageChanged(position);
     }
   }
 }

src/org/thoughtcrime/securesms/mediasend/MediaSendFragmentPagerAdapter.java

@@ -9,6 +9,8 @@ import androidx.fragment.app.FragmentStatePagerAdapter;
 import android.view.View;
 import android.view.ViewGroup;
 
+import com.annimon.stream.Stream;
+
 import org.thoughtcrime.securesms.scribbles.ImageEditorFragment;
 import org.thoughtcrime.securesms.util.MediaUtil;
 
@@ -119,4 +121,21 @@ class MediaSendFragmentPagerAdapter extends FragmentStatePagerAdapter {
   @Nullable View getPlaybackControls(int position) {
     return fragments.containsKey(position) ? fragments.get(position).getPlaybackControls() : null;
   }
+
+  void notifyHidden() {
+    Stream.of(fragments.values()).forEach(MediaSendPageFragment::notifyHidden);
+  }
+
+  void notifyPageChanged(int currentPage) {
+    notifyHiddenIfExists(currentPage - 1);
+    notifyHiddenIfExists(currentPage + 1);
+  }
+
+  private void notifyHiddenIfExists(int position) {
+    MediaSendPageFragment fragment = fragments.get(position);
+
+    if (fragment != null) {
+      fragment.notifyHidden();
+    }
+  }
 }

src/org/thoughtcrime/securesms/mediasend/MediaSendGifFragment.java

@@ -65,4 +65,8 @@ public class MediaSendGifFragment extends Fragment implements MediaSendPageFragm
 
   @Override
   public void restoreState(@NonNull Object state) { }
+
+  @Override
+  public void notifyHidden() {
+  }
 }

src/org/thoughtcrime/securesms/mediasend/MediaSendPageFragment.java

@@ -19,4 +19,6 @@ public interface MediaSendPageFragment {
   @Nullable Object saveState();
 
   void restoreState(@NonNull Object state);
+
+  void notifyHidden();
 }

src/org/thoughtcrime/securesms/mediasend/MediaSendVideoFragment.java

@@ -59,6 +59,19 @@ public class MediaSendVideoFragment extends Fragment implements MediaSendPageFra
     }
   }
 
+  @Override
+  public void onPause() {
+    super.onPause();
+    notifyHidden();
+  }
+
+  @Override
+  public void onHiddenChanged(boolean hidden) {
+    if (hidden) {
+      notifyHidden();
+    }
+  }
+
   @Override
   public void setUri(@NonNull Uri uri) {
     this.uri = uri;
@@ -82,4 +95,11 @@ public class MediaSendVideoFragment extends Fragment implements MediaSendPageFra
 
   @Override
   public void restoreState(@NonNull Object state) { }
+
+  @Override
+  public void notifyHidden() {
+    if (getView() != null) {
+      ((VideoPlayer) getView()).pause();
+    }
+  }
 }

src/org/thoughtcrime/securesms/scribbles/ImageEditorFragment.java

@@ -212,6 +212,10 @@ public final class ImageEditorFragment extends Fragment implements ImageEditorHu
     }
   }
 
+  @Override
+  public void notifyHidden() {
+  }
+
   private void changeEntityColor(int selectedColor) {
     if (currentSelection != null) {
       Renderer renderer = currentSelection.getRenderer();