ALSpotlightView 介绍
ALSpotlightView 是焦点视图控制，使用 Swift 实现。
//-- Initializing a spotlight view (shortest initialization):
let spotlightView = ALSpotlightView(spotlightCenter: CGPoint(x: 0.5, y: 0,5))
//-- Setting a tap handler (to hide when tapped)
spotlightView.onTapHandler = {
spotlightView.hide
}
//-- Presenting the spotlight view:
spotlightView.show()