setSystemUiVisibility() 与 getSystemUiVisibility() 显示隐藏状态栏
用于备忘:Android4.4Camera源码里面有一个操作界面的方法:/***If{@paramvisible}isfalse,thishidestheactionbarandswitchesthe*systemUItolights-outmode.If{@paramhideLater}istrue,adelayedmessage*willbesentafteratimeouttohidethe