const dHeight = Dimensions.get('window').height;

const dWidth = Dimensions.get('window').width;

const sHeight = Dimensions.get('screen').height;

const sWidth = Dimensions.get('screen').width;

状态栏高度：statusBarHeight

安卓底部虚拟导航条高度：botNavHeight

应用显示高度：aHeight

对于iOS：

dHeight = sHeight

dWidth = sWidth

dHeight = statusBarHeight + aHeight

对于安卓：

  非全面屏：

  dHeight = statusBarHeight + aHeight

  sHeight = dHeight + botNavHeight

  dWidth = sWidth

  全面屏：

  dHeight = aHeight

  sHeight = statusBarHeight+ dHeight + botNavHeight

  dWidth = sWidt