这篇文章记录一下如何通过LoadControl来控制exoplayer2默认的预加载机制
可以通过CacheDataSourceFactory来实现本地缓存的功能. 凡是下载的数据会在设定的缓存目录中保存下来, 如下是一个示例:
DefaultDataSourceFactory dataSourceFactory = new DefaultDataSourceFactory(VUtil.getApplication(),
Util.getUserAgent(VUtil.getApplication(), VUtil.getApplication().getString(R.string.app_name)));
File cacheFile = new File(VUtil.getApplication().getExternalCacheDir().getAbsolutePath(), "video");
VLog.d(TAG, "PlayerWrapper() cache file:" + cacheFile.getAbsolutePath());
SimpleCache simpleCache = new SimpleCache(cacheFile, new LeastRecentlyUsedCacheEvictor(512 * 1024 * 1024)); // 本地最多保存512M, 按照LRU原则删除老数据
CacheDataSourceFactory cachedDataSourceFactory = new CacheDataSourceFactory(simpleCache, dataSourceFactory);
手机数据业务下的预加载控制
自定义一个LoadControl对象 , LdDefaultLoadControl
具体实现可以参考Exoplayer2中附带的实现om.google.android.exoplayer2.DefaultLoadControl
唯一要修改的地方是:
public boolean shouldContinueLoading(long bufferedDurationUs)
自定义的具体实现:
@Override
public boolean shouldContinueLoading(long bufferedDurationUs) {
if (!VUtil.isWifiConnected(VUtil.getApplication())) {//如果没有wifi连接则判断是否是用户主动播放
if(!userAction){
return false; // 如果不是用户主动点击播放, 那就是预加载了, 那么返回, 不再预加载
}
}
int bufferTimeState = getBufferTimeState(bufferedDurationUs);
boolean targetBufferSizeReached = allocator.getTotalBytesAllocated() >= targetBufferSize;
boolean wasBuffering = isBuffering;
isBuffering = bufferTimeState == BELOW_LOW_WATERMARK
|| (bufferTimeState == BETWEEN_WATERMARKS && isBuffering && !targetBufferSizeReached);
if (priorityTaskManager != null && isBuffering != wasBuffering) {
if (isBuffering) {
priorityTaskManager.add(C.PRIORITY_PLAYBACK);
} else {
priorityTaskManager.remove(C.PRIORITY_PLAYBACK);
}
}
return isBuffering;
}
另外对于参数userAction的定义:
// 用来记录当前的播放动作是否是用户主动事件, 因为在数据业务模式下需要用户同意才能播放视频
// 这个值在外围生成LdDefaultLoadControl对象时作为参数传进来
private boolean userAction;
/**
* Constructs a new instance, using the {@code DEFAULT_*} constants defined in this class.
*/
public LdDefaultLoadControl(boolean userAction) {
this(new DefaultAllocator(true, C.DEFAULT_BUFFER_SEGMENT_SIZE));
this.userAction = userAction;
}
