这两天在练习swift的项目中遇到了一个难题，就是闭包的使用，在网络封装中或者是界面传值中，用OC中的block块传值很方便直观，在swift中却有些晕，经过搜索资料，终于解决了
主要是闭包的定义和使用,模拟一个场景，TopScrollView中点击按钮，利用闭包将所需的参数传递给控制器HomeViewController使用，控制器中调用闭包
1.在TopScrollView中定义闭包
class TopScrollView: UIScrollView {
var config:ItemConfig!
var currentIndex:Int = 0
var lineView:UIView!
var tapAnimation:Bool?
//闭包的两种定义方法
//1.
typealias blockClosure = (Int,Bool) ->Void
var didClickItemBlock:blockClosure?
//2.
//var itemDidClickBlock:((Int,Bool) ->Void)?
}
- 闭包的定义就完成了，下面是触发闭包，用来传值
@objc private func itemButtonClick(button:UIButton) {
currentIndex = button.tag - 100
if tapAnimation! {
}else {
changeItemColor(index: Float(currentIndex))
changeLine(index: Float(currentIndex))
}
changeScrollOffset(index: Float(currentIndex))
// topScrollViewDelegate!.topScrollViewDidClickItem(index: currentIndex, animation: tapAnimation!)
if didClickItemBlock != nil {
didClickItemBlock!(currentIndex,tapAnimation!)
}
}
- 最后是在控制器中接收传递过来的值，做相应操作
private func setupTopScrollView() {
let config = ItemConfig()
config.itemWidth = view.width / 4.0
topScrollView = TopScrollView(frame: CGRect(x: 0, y: 0, width: view.bounds.size.width, height: 40))
topScrollView.config = config
let array = ["视频","直播","图集","小清新","程序设计","新闻","天气预报","段子","政治"]
topScrollView.setupDataSource(array:array as NSArray)
topScrollView.topScrollViewDelegate = self
view.addSubview(topScrollView)
topScrollView.didClickItemBlock = { (index,tapAnimation) in
self.mainCollectionView.scrollRectToVisible(CGRect(x: CGFloat(index) * self.mainCollectionView.width, y: 0.0, width: self.mainCollectionView.width, height: self.mainCollectionView.height), animated: tapAnimation)
}
}
整个闭包的使用就是这样，其实和block块很像，弄懂了也不是那么可怕，下面附一个简单网络请求中的闭包使用
class NetworkTool: NSObject {
typealias successBlock = (Any?) ->Void
typealias failureBlock = (NSError) ->Void
func GetRequest(urlString:String,parameters:[String:Any]?,success:successBlock?,failure:failureBlock?) {
let manager = AFHTTPSessionManager()
manager.get(urlString, parameters: parameters, progress: {(progress) in
}, success: {(task, response) in
if success != nil {
success!(response)
}
}, failure: {(task, error) in
if failure != nil {
failure!(error as NSError)
}
})
}
}