这是用qt做的播放器，实现的功能有：添加播放文件到列表，双击屏幕可以全屏，拉进度条能够快进到所要到的地方。-This is to do with qt player, realized the function: to add to the list to play the file, double-click the screen for full-screen, want to pull the progress bar to fast forward to the