Google Cast Function

依赖
com.android.support:mediarouter-v7
com.google.android:gms:play-services-cast-framework

Cast 过程
1）framework提供一个CastContext singleton给APP使用
2）MediaRoute 提供设备扫描
3）CastSession (由CastContext.getSessionManager().getCurrentCastSession()提供) 通过用户选取MediaRouter扫描dialog建立device connect
4）RemoteMediaClient ( 由castsession 得到mCastSession.getRemoteMediaClient())控制Receiver device 的音视频play,pause,etc
5）MediaMetadata代表需要cast mediaitem

privateMediaInfo buildMediaInfo() {

MediaMetadata movieMetadata = newMediaMetadata(MediaMetadata.MEDIA_TYPE_MOVIE);

movieMetadata.putString(MediaMetadata.KEY_SUBTITLE,mSelectedMedia.getStudio());

movieMetadata.putString(MediaMetadata.KEY_TITLE, mSelectedMedia.getTitle());

movieMetadata.addImage(new WebImage(Uri.parse(mSelectedMedia.getImage(0))));

movieMetadata.addImage(new WebImage(Uri.parse(mSelectedMedia.getImage(1))));

return new MediaInfo.Builder(mSelectedMedia.getUrl())

.setStreamType(MediaInfo.STREAM_TYPE_BUFFERED)

.setContentType("videos/mp4")

.setMetadata(movieMetadata)

.setStreamDuration(mSelectedMedia.getDuration() * 1000)

.build();

}

6）RemoteMediaClient 控制Receiver device load
remoteMediaClient.load(buildMediaInfo(),autoPlay, position);