Question

我想使用NSMutableArray在动态表视图中添加搜索，实际上我使用json在表中添加产品所以我需要NSMutableArray

首先我将值分配为

var filteredItems = [String]()
var searchController:UISearchController!
var products:NSMutableArray = NSMutableArray()

我正在使用moltin API并使用NSArray。

        if let newProducts:NSArray = response?["result"] as? NSArray {
            self.products.addObjects(from: newProducts as [AnyObject])

        }


        let responseDictionary = NSDictionary(dictionary: response!)

        if let newOffset:NSNumber = responseDictionary.value(forKeyPath: "pagination.offsets.next") as? NSNumber {
            self.paginationOffset = newOffset.intValue

我也将它用于细胞

let cell = tableView.dequeueReusableCell(withIdentifier: CELL_REUSE_IDENTIFIER, for: indexPath) as! ProductsListTableViewCell

    let row = (indexPath as NSIndexPath).row



let product:NSDictionary = products.object(at: row) as! NSDictionary

    cell.configureWithProduct(product)

    return cell

在视图中，我使用导航栏上搜索栏的正确方法加载了我。

我使用此功能过滤结果，但它无法正常工作并发出错误：

无法将值转换为类型（_） - ＆gt; _接受参数类型＆＃39; NSPredict＆＃39;

func updateSearchResults(for searchController: UISearchController) {
    filteredItems.removeAll(keepingCapacity: false)

    // filter
    filteredItems = products.filter{
        item in

        item.lowercased().contains(searchController.searchBar.text!.lowercased())
    }

    tableView.reloadData()

}

但是，当我使用简单的项目数组时，它对我来说非常有效。我如何在 NSMutableArray 中使用它？

Answer 1

首先，使用json 并不意味着你需要NSMutableArray 。

我会将您的代码重写为：

（假设NSDictionary?是var products: [String] = []而响应[＆＃34;结果＆＃34;]是一个字符串数组。如果这个假设与您的情况不符，您可能需要添加更多有关响应[＆＃34;结果＆＃34;]包含的信息。）

    if let newProducts = response?["result"] as? [String] {
        self.products.append(contentsOf: newProducts)
    }

和

filteredItems = ...

通过此更改，您的NSMutableArray无需任何修改即可正常使用。

如果你坚持使用filteredItems = (products as NSArray as! [String]).filter { item in item.lowercased().contains(searchController.searchBar.text!.lowercased()) }，你可能需要写这样的东西：

    filteredItems = products.filter {
        item in

        (item as! String).lowercased().contains(searchController.searchBar.text!.lowercased())
    }.map{$0 as! String}

或者这个：

 // postlab.cpp 
//   this program implements a student database 
//   user can print, and search by 
//     lastname, email, area code, and city
//    
//   HINT to search by area code, use the
//    C++ string substring function, for example
//        string s = "hamburger";
//        cout<<s.substr(3,4);   // prints burg
//
//    http://www.cplusplus.com/reference/string/string/substr/

#include<iostream>
#include<fstream>
#include<cstdlib>
#include "Student.h"
using namespace std;


void get_stream(ifstream& ins);
int menu();                                      // print the menu of choicse
void print_list(int size, Student s[]);    // print the whole list
void ln_search(int size, Student s[]);     // search database for last name
void email_search(int size, Student s[]);  // search for an email address
void ac_search(int size, Student s[]);     // search for all in an area code
void city_search(int size, Student s[]);   // search for all in a city

int main( )
{
     int size, count, choice;

     ifstream ins;
     get_stream(ins);

     ins >> size;  // the first value in file is the number of records
     Student *dbase = new Student[size]; // to store student's data in 
                                         // student array      
     for (int k=0; k<size; k++){
        ins >> dbase[k];
        cout << dbase[k]<<endl;
     }

     // database read, now we process it
     do {
        choice = menu(); // display menu and input choice

        // process user choice
        switch(choice){
            case 1:
                print_list(size,dbase);
                break;
            case 2:  
                ln_search(size,dbase);
                break;
        }
     } while (choice != 6);  // 6 is exit command


     return 0;
}


void get_stream(ifstream& ins)
{
    ins.open("student.txt");
    if(ins.fail())
    {
       cout << "Failed to open the input file. \n";
       exit(1);
    }
}

int menu()                                      // print the menu of choicse
{
    int choice;
    cout<<"Student Database Processor"<<endl;
    cout<<"Menu:"<<endl;
    cout<<"1 - Print All Students"<<endl;
    cout<<"2 - Search by Last Name"<<endl;
    cout<<"3 - Search by email address"<<endl;
    cout<<"4 - Print All Students with Requested Area Code"<<endl;
    cout<<"5 - Print All Students Living in Requested City"<<endl;
    cout<<"6 - Exit"<<endl<<endl;

    cout<<"Enter your choice"<<endl;
    cin>>choice;
    return choice;
}

void print_list(int size, Student s[])    // print the whole list
{
    cout << "Student database contain: " << endl; 
    for (int k = 1; k<size; k++)
      cout << k << "-" << s[k] << endl; 

    // write a for loop and print all students in s.
    // remember, s is an array, so, cout<<s[k]<<endl;

}

void ln_search(int size, Student s[])
{ 
  string ln; 
  cout << "Enter the last name: " << endl; 
  cin >> ln ; 
   for(int k = 0 ;k<size;k++){ 

       if(ln == s[k].lastname) 
        cout<< "Found"; 
        cout<<s[k] << endl; 
         // of the last name we entered
}

}

如果上述代码无法解决您的问题，您可能需要修改问题以提供更多信息。

如何在NSMutableArray

1 个答案: