如何在VideoView中修复黑屏

我将Firebase存储作为临时文件下载到设备中后想从Firebase存储中播放视频，但是我听到的声音不是视频，请帮忙（对不起我的英语）

这是我的xml

RelativeLayout
    android:id="@+id/videoContainer"
    android:layout_width="match_parent"
    android:layout_height="200dp"
    android:background="#000"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent" >
    <VideoView
        android:layout_width="match_parent"
        android:background="#000"
        android:id="@+id/player_view"
        android:layout_gravity="center"
        android:layout_height="250dp"/>
</RelativeLayout>

这是我的actvity.java

FirebaseStorage storage = FirebaseStorage.getInstance();

    StorageReference storageRef = storage.getReference("Movies/trailer/tt.mp4");
    try {
        final File localFileSave = File.createTempFile("Movies", "mp4");

        storageRef.getFile(localFileSave).addOnCompleteListener(new OnCompleteListener<FileDownloadTask.TaskSnapshot>() {
            @Override
            public void onComplete(@NonNull Task<FileDownloadTask.TaskSnapshot> task) {
                Toast.makeText(MovieDetails.this, "DownloadComplete", Toast.LENGTH_LONG);

                moviePlayer = findViewById(R.id.player_view);
                moviePlayer.setVideoURI(Uri.fromFile(localFileSave));
                ProgressBar progressBar = new ProgressBar(MovieDetails.this);
                MediaController mediaController = new MediaController(MovieDetails.this);
                mediaController.setAnchorView(moviePlayer);
                moviePlayer.setMediaController(mediaController);
                moviePlayer.requestFocus();
                moviePlayer.start();

            }
        });


    } catch (IOException e) {
        e.printStackTrace();
    }

我只听到声音，我都想要！我在哪里做错了？