到目前为止,这个想法非常简单,用户搜索与搜索栏文本匹配的电影,这会触发一个请求,用UfuableView填充结果.使用在线发现的教程和示例,我已经设法实现了这一点而没有太多麻烦.
当我试图加载通过滚动表格视图底部触发的下一页结果时,棘手的部分就出现了.
这是到目前为止使用的代码：
public final class Homeviewmodel: NSObject {
// MARK: - Properties
var searchText: Variable<String> = Variable("")
var loadNextPage: Variable<Void> = Variable()
lazy var pages: Observable<PaginatedList<Film>> = self.setupPages()
// MARK: - Reactive Setup
fileprivate func setupPages() -> Observable<PaginatedList<Film>> {
return self.searchText
.asObservable()
.debounce(0.3,scheduler: MainScheduler.instance)
.distinctUntilChanged()
.flatMapLatest { (query) -> Observable<PaginatedList<Film>> in
return TMDbAPI.Films(withTitle: query,atPage: 0)
}
.shareReplay(1)
}
}
这是我到目前为止：可观察的页面绑定到HomeViewController中的表视图,其搜索栏文本绑定到searchText.
我正在使用Alamofire在幕后执行API调用,TMDbAPI.Films(withTitle：query)返回一个Observable的分页列表.
这是我的模型结构PaginatedList
public struct PaginatedList<T> {
// MARK: - Properties
let page: Int
let totalResults: Int
let totalPages: Int
let results: [T]
// MARK: - Initializer
init(page: Int,totalResults: Int,totalPages: Int,results: [T]) {
self.page = page
self.totalResults = totalResults
self.totalPages = totalPages
self.results = results
}
// MARK: - Helper functions / properties
var count: Int { return self.results.count }
var nextPage: Int? {
let nextPage = self.page + 1
guard nextPage < self.totalPages else { return nil }
return nextPage
}
static func Empty() -> PaginatedList { return PaginatedList(page: 0,totalResults: 0,totalPages: 0,results: []) }
}
extension PaginatedList {
// MARK: - Subscript
subscript(index: Int) -> T {
return self.results[index]
}
}
我现在正在寻找一种反应方式来将我的loadNextPage变量挂钩到分页列表的observable,它会触发对下一页的请求.
当搜索栏文本发生变化时,它会将分页重置为0.
我相信需要使用运算符扫描和连接,但我仍然不确定如何…
如何实现这一点的任何建议将非常感谢…
// Some kind of page request result. Modify it to be what you're using.
struct SomePageResult {
let content: String
}
// Needs modification to return your actual data
func getPage(query: String,number: UInt) -> SomePageResult {
return SomePageResult(content: "some content for search (\(query)) on page \(number)")
}
// Actual implementation
let disposeBag = disposeBag()
var loadNextPage = PublishSubject<Void>()
var searchText = PublishSubject<String>()
let currentPage = searchText
.distinctUntilChanged()
.flatMapLatest { searchText in
return loadNextPage.asObservable()
.startWith(())
.scan(0) { (pageNumber,_) -> UInt in
pageNumber + 1
}
.map { pageNumber in
(searchText,pageNumber)
}
}
.map { (searchText,pageNumber) in
getPage(searchText,number: pageNumber)
}
currentPage
.subscribeNext { print($0) }
.adddisposableto(disposeBag)
searchText.onNext("zebra")
searchText.onNext("helicopter")
loadNextPage.onNext()
searchText.onNext("unicorn")
searchText.onNext("unicorn")
searchText.onNext("ant")
loadNextPage.onNext()
loadNextPage.onNext()
loadNextPage.onNext()
输出：
SomePageResult(content: “some content for search (zebra) on page 1”) SomePageResult(content: “some content for search (helicopter) on page 1”) SomePageResult(content: “some content for search (helicopter) on page 2”) SomePageResult(content: “some content for search (unicorn) on page 1”) SomePageResult(content: “some content for search (ant) on page 1”) SomePageResult(content: “some content for search (ant) on page 2”) SomePageResult(content: “some content for search (ant) on page 3”) SomePageResult(content: “some content for search (ant) on page 4”)