on Android TrackPlayer.move(from, to) was wrong

[andy380743909]

Describe the Bug
I have a queue with ABCDE five songs.
after TrackPlayer.move(4, 1) on Android
from = 4
to = 1

I got a new queue:

0 E <- the E was inserted at 0
1 A
2 B
3 C
4 D

I compared the source code of iOS and Android:

/////// iOS

/**
     Move an item in the queue.

     - parameter fromIndex: The index of the item to be moved.
     - parameter toIndex: The index to move the item to. If the index is larger than the size of the queue, the item is moved to the end of the queue instead.
     - throws: AudioPlayerError.QueueError
     */
    public func moveItem(fromIndex: Int, toIndex: Int) throws {
        try synchronizeThrows {
            try throwIfQueueEmpty();
            try throwIfIndexInvalid(index: fromIndex, name: "fromIndex")
            try throwIfIndexInvalid(index: toIndex, name: "toIndex", max: Int.max)
            
            let item = items.remove(at: fromIndex)
            self.items.insert(item, at: min(items.count, toIndex));
            if (fromIndex == currentIndex) {
                currentIndex = toIndex;
            }
        }
    }

////// Android

/**
     * Move an item in the queue from one position to another.
     * @param fromIndex The index of the item ot move.
     * @param toIndex The index to move the item to. If the index is larger than the size of the queue, the item is moved to the end of the queue instead.
     */
    fun move(fromIndex: Int, toIndex: Int) {
        exoPlayer.moveMediaItem(fromIndex, toIndex)
        val item = queue[fromIndex]
        queue.removeAt(fromIndex)
        queue.add(max(0, min(items.size, if (toIndex > fromIndex) toIndex else toIndex - 1)), item)
    }

And Android have one more issue, after move, if I skip to next , the player played the song which was at the index before move

[lovegaoshi]

androids exoolayer has a built in queue wheras ios elected avplayer not avqueueplayer, so for Android there are 2 queues - one in exoolayer and another in the native layer. it could be a queue out of sync or not behaving as expected. id recommend logging both queues after calling move as a starter. hard to judge what happened only looking at the code

[andy380743909]

d1418db1059a46e13a7a4e4b2bebd9bd.mp4

After I drag to sort the songs, I use the move API to change the queue of TrackPlayer. The move implementation of Android has error.

react-native-track-player/android/src/main/java/com/doublesymmetry/kotlinaudio/players/QueuedAudioPlayer.kt

Line 201 in 359af5a

fun move(fromIndex: Int, toIndex: Int) {

fun move(fromIndex: Int, toIndex: Int) {
        exoPlayer.moveMediaItem(fromIndex, toIndex)
        val item = queue[fromIndex]
        queue.removeAt(fromIndex)
        queue.add(max(0, min(items.size, if (toIndex > fromIndex) toIndex else toIndex - 1)), item) // WHY toIndex - 1 when (toIndex < from Index) ???
    }

// WHY toIndex - 1 when (toIndex < from Index) ???

The iOS version is correct.

Currently I did a fix at the JS level by this:

const logQueue = (label: string, queue: Track[]) => {
        console.log(label);
        queue.forEach((t, index) => {
            console.log(`${index}: ${t.title} (${t.id})`);
        });
    };

    const handleDragEnd = async ({ data, from, to }: { data: Track[]; from: number; to: number }) => {
        if (from === to) return;

        console.log('Drag end:', { from, to });

        // 打印拖拽前队列（data 是更新后的队列，先打印 setQueue 前的旧队列）
        logQueue('Queue before move:', queue);

        const playerQueue = await TrackPlayer.getQueue();
        logQueue('TrackPlayer Queue before move:', playerQueue);


        try {
            // 移动队列
            // Android 平台特殊处理
            let moveToIndex = to;
            if (Platform.OS === 'android' && from > to) {
                moveToIndex = to + 1;
            }

            await TrackPlayer.move(from, moveToIndex);

            // 打印拖拽后队列
            const newQueue = await TrackPlayer.getQueue();
            logQueue('Queue after move:', newQueue);

            // 更新 UI 队列
            setQueue(newQueue);

        } catch (err) {
            console.error('Error moving track:', err);
        }
    };

So the UI can show the right result after dragging, or it shows the wrong order.

But this only fix the UI bug. If I play prev or next song, it play the wrong song.

[andy380743909]

https://github.com/doublesymmetry/SwiftAudioEx/blob/42767039eb8e2a3caef81e39d4c66de26d6b9944/Sources/SwiftAudioEx/QueueManager.swift#L248

iOS version is OK