ios - 自动完成搜索在从数据库中获取结果时变慢并占用内存

Question

你好，我已经在我的应用程序上实现了自动完成搜索。当用户键入任何字符或单词时，我将城市存储在我的 mysql 数据库和应用程序中，应用程序从数据库中获取结果并显示它。我遇到的问题是数据库中存储了 1000 多个城市，当用户说输入一个字符时，我的应用程序键盘有点卡住了，它在获取结果并显示时占用了大量内存。有没有更好的方法来实现这种功能。请查看我的代码，让我知道我应该对我的代码进行哪些更改

func updateSearchResultsForSearchController(searchController: UISearchController) {
        filterTableData.removeAll(keepCapacity: false)
        let searchWord = searchController.searchBar.text!

        getCityNamesFromServer(searchWord)

        let searchPredict = NSPredicate(format: "SELF CONTAINS[c] %@", searchController.searchBar.text!)

        for var i = 0; i < self.dict.count; i++ {
            let cityname = (((self.dict["\(i)"] as?NSDictionary)!["City"] as?NSDictionary)!["name"] as?NSString)! as String
        newTableData.append(cityname)
        }

        let array = (newTableData as NSArray).filteredArrayUsingPredicate(searchPredict)
        print("array is\(array)")
        filterTableData = array as! [String]
        self.tableView.reloadData()
    }

完整代码:

class  CityTableViewController: UITableViewController, UISearchResultsUpdating {
    var dict = NSDictionary()
    var filterTableData = [String]()
    var resultSearchController = UISearchController()


    var newTableData = [String]()


    override func viewDidLoad() {
        super.viewDidLoad()



        self.resultSearchController = ({

            let controller  = UISearchController(searchResultsController: nil)
            controller.searchResultsUpdater = self
            controller.dimsBackgroundDuringPresentation = false
            controller.searchBar.sizeToFit()
            self.tableView.tableHeaderView = controller.searchBar
            return controller


        })()

        self.tableView.reloadData()
    }

    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {


        if(self.resultSearchController.active){

            return self.filterTableData.count
        }else {

            return dict.count
        }



    }



    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

        let cell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath) as! CountryTableViewCell

        if(self.resultSearchController.active){

            cell.cityNameLabel.text = filterTableData[indexPath.row]
            return cell

        }else{

            cell.cityNameLabel.text = (((self.dict["\(indexPath.row)"] as?NSDictionary)!["City"] as?NSDictionary)!["name"] as?NSString)! as String
            return cell
        }



    }

    func updateSearchResultsForSearchController(searchController: UISearchController) {
        filterTableData.removeAll(keepCapacity: false)
        let searchWord = searchController.searchBar.text!

        getCityNamesFromServer(searchWord)

        let searchPredict = NSPredicate(format: "SELF CONTAINS[c] %@", searchController.searchBar.text!)
        print("searchPredict is \(searchController.searchBar.text!)")

        for var i = 0; i < self.dict.count; i++ {
            let cityname = (((self.dict["\(i)"] as?NSDictionary)!["City"] as?NSDictionary)!["name"] as?NSString)! as String
        newTableData.append(cityname)
        }

        let array = (newTableData as NSArray).filteredArrayUsingPredicate(searchPredict)
        print("array is\(array)")
        filterTableData = array as! [String]
        self.tableView.reloadData()
    }






    func getCityNamesFromServer(searchWord:String){


        let url:String = "http://localhost/"
        let params = ["city":searchWord]



        ServerRequest.postToServer(url, params: params) { result, error in

            if let result = result {
                print(result)

                self.dict = result

            }
        }

    }

}

Answer 1

限制返回数据量的最佳方法是在查询中添加 LIMIT 子句。示例 SQL 查询:

SELECT name FROM cities WHERE name like '%something%';

将此更改为:

SELECT name FROM cities  WHERE name like '%something%' LIMIT 10;

从用户的角度来看，返回 1000 行没有意义，无论如何您都无法显示它，因此您必须想出一个适合屏幕的数字。在任何额外的按键之后，您可以使用更新的搜索字符串重复查询。