use surfaceview and mediaplayer to play local and net video
this demo can play local video and video in network , if the video is in network , then it will download the video in another thread , when finished the video will be played automatically.
Progress is shown when playing , and you can pull the progressbar to any position.
When clicked, the play button can show/hide.
When pressing Home key, it will save the position . And when comeback , the video will be played from the position where you paused.
