释放PagerAdapter中的资源

Question

我有一个PagerAdapter，并在instantiateItem中初始化了一个ExoPlayer。

我的问题是，如何释放播放器？

[我认为，某种程度上应该包含函数destroyItem，但是destroyItem仅将视图作为对象。如何释放PagerAdapter这一项目的专用资源？

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override fun instantiateItem(container: ViewGroup, position: Int): Any {
    [...]
        url.contains(mContext.getString(R.string.video_file_indicator)) -> {

            val exoPlayer = ExoPlayerFactory.newSimpleInstance(mContext)
            videoView.player = exoPlayer

            val dataSourceFactory : DataSource.Factory = DefaultDataSourceFactory(mContext, Util.getUserAgent(mContext, mContext.getString(R.string.app_name)))
            var videoSource : MediaSource = ProgressiveMediaSource.Factory(dataSourceFactory).createMediaSource(Uri.parse(url))
            if (url == Helper.getUserProfile().profileVideoUrl) {
                val localFile = File(mContext.getExternalFilesDir(null), Helper.profilePicVideoName)
                videoSource = ProgressiveMediaSource.Factory(dataSourceFactory).createMediaSource(localFile.toUri())                   
            }
            exoPlayer.prepare(videoSource)
            exoPlayer.playWhenReady = true
            exoPlayer.repeatMode = Player.REPEAT_MODE_ONE 
            videoView.resizeMode = AspectRatioFrameLayout.RESIZE_MODE_ZOOM
        }          
    }
    container.addView(layout)
    return layout
}

override fun destroyItem(container: ViewGroup, position: Int, `object`: Any) {
    container.removeView(`object` as View)
}

Answer 1

您不需要从方法View返回instantiateItem()，也可以返回包含ExoPlayer和View的包装器。

例如

data class Wrapper(val view: View, val player: ExoPlayer)

以及您的PagerAdapter：

override fun instantiateItem(container: ViewGroup, position: Int): Any {
    [...]
    return Wrapper(layout, exoPlayer)
}

override fun destroyItem(container: ViewGroup, position: Int, `object`: Any) {
    val wrapper = `object` as Wrapper
    container.removeView(wrapper.view)
    // Release the player here.
    wrapper.player.doSomething()
}

如果要改为从instantiateItem()返回视图，则可以将ExoPlayer分配为视图的标签，以便以后检索。

例如

override fun instantiateItem(container: ViewGroup, position: Int): Any {
    [...]
    return layout.apply {
        setTag(exoPlayer)
    }
}

override fun destroyItem(container: ViewGroup, position: Int, `object`: Any) {
    val view = `object` as View
    container.removeView(view)
    // Release the player here.
    val exoPlayer = view.getTag() as ExoPlayer
    exoPlayer.doSomething()
}