ios - Objective-C 重复解析对象中的行

Question

我一直被这个问题困扰了一段时间。基本上我一直在尝试从解析中提取结果列表，然后从关系指针中获取信息。

我已经到了可以将单元格标签设置为标题的地步，但返回的行数似乎相同。

我知道我需要在某处使用 indexPath.row，但我想不出如何使用。

任何帮助将不胜感激:)

   //
//  DEMOWatchedGamesTableViewController.m
//  ShoutOutz
//
//  Created by Craig Turner on 05/08/2014.
//  Copyright (c) 2014 Roman Efimov. All rights reserved.
//

#import "DEMOWatchedGamesTableViewController.h"
#import <Parse/Parse.h>

@interface DEMOWatchedGamesTableViewController ()

@end

NSMutableArray *arrayGames;

@implementation DEMOWatchedGamesTableViewController

- (void)viewDidLoad
{
    [super viewDidLoad];


    // Uncomment the following line to preserve selection between presentations.
    // self.clearsSelectionOnViewWillAppear = NO;

    // Uncomment the following line to display an Edit button in the navigation bar for this view controller.
    // self.navigationItem.rightBarButtonItem = self.editButtonItem;

    //PFUser *currentUser = [PFUser currentUser];

    PFQuery *query = [PFQuery queryWithClassName:@"watched_games"];



    // Include the user data with each post
    [query includeKey:@"game_id"];


    [query findObjectsInBackgroundWithBlock:^(NSArray *postObjects, NSError *error)
     {
         if(!error){

             NSLog(@"myArray: %@", postObjects);


             self.myArray = postObjects;

             [self.tableView reloadData];


         } else {
             NSLog(@"Error: %@ %@", error, [error userInfo]);
         }

     }];


}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

#pragma mark - Table view data source

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    return 1;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return [self.myArray count];
    //return 3;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    static NSString *cellIdentifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];

    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:cellIdentifier];
    }


    NSLog(@"Array: %@", self.myArray);

    for (PFObject * postObject in self.myArray) {


        [postObject fetchIfNeededInBackgroundWithBlock:^(PFObject *object, NSError *error){

            PFObject *postAuthor = [object objectForKey:@"game_id"];


            NSLog(@"retrieved related Post Author: %@", postAuthor);

            cell.textLabel.text = [postAuthor objectForKey:@"gameTitle"];


        }];
    }

    return cell;
}

/*
// Override to support conditional editing of the table view.
- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath
{
    // Return NO if you do not want the specified item to be editable.
    return YES;
}
*/

/*
// Override to support editing the table view.
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
    if (editingStyle == UITableViewCellEditingStyleDelete) {
        // Delete the row from the data source
        [tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];
    } else if (editingStyle == UITableViewCellEditingStyleInsert) {
        // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
    }   
}
*/

/*
// Override to support rearranging the table view.
- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath
{
}
*/

/*
// Override to support conditional rearranging of the table view.
- (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath
{
    // Return NO if you do not want the item to be re-orderable.
    return YES;
}
*/

/*
#pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.
}
*/


@end

Answer 1

请记住，tableView:cellForRowAtIndexPath: 方法会为每个需要显示的单元格调用一次，这取决于您在 tableView:numberOfRowsInSection 中提供的值数据源方法，在本例中为 myArray 数组的大小。

因此，根据该原则，您无需为 cellForRowAtIndexPath 方法的每次迭代都遍历数组。此方法的有用之处在于，它通过向您提供 indexPath 让您知道它将创建哪个单元格索引。因此，您可以使用该方法提供的 indexPath 值作为索引，然后像这样在数组中获取适当的实例:

这只是一个基于您现有代码的示例:

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    static NSString *cellIdentifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];

    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:cellIdentifier];
    }

    /**
      Why are you printing the array? youll end up printing it as many times as there are instances
      in your myArray array. You dont want to do that ;)
      NSLog(@"Array: %@", self.myArray);
    */

    //Using the indexpath's row value we can go ahead and grab that from your myArray array
    PFObject * postObject = [self.myArray objectAtIndex:indexPath.row];

    [postObject fetchIfNeededInBackgroundWithBlock:^(PFObject *object, NSError *error){
        PFObject *postAuthor = [object objectForKey:@"game_id"];
        NSLog(@"retrieved related Post Author: %@", postAuthor);
        cell.textLabel.text = [postAuthor objectForKey:@"gameTitle"];
    }];
    return cell;
}