// // EDIT

Question

好的，所以我一直在摆弄一些iOS开发，我对此很陌生。通常更多的是PHP和JavaScript的人。但这是我的问题...在我的应用程序中我正在创建从本地xml文件中提取一个friendslist（它将指向生成用户friendslist的服务器上的php页面，但为了简单起见，我调试和开发）使用本地。）

我有一个View Controller（storybaord），当我点击“friends”时加载，截至目前，视图加载但没有数据，在调试器中我可以看到它从XML中提取数据，所以我想，好吧也许TableView永远不会被调用，所以我在

上放了一个断点

 - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath

但该应用仍然继续加载页面，

所以回顾一下我有一个View Controller，带有搜索栏，工具栏和一个表视图，表视图有一个占位符单元格给定标识符Cell，下面是为friendsListTableViewController.h编码的

//
//  friendsListTableViewController.h
//  @ME
//
//  Created by Aaron Russell on 1/22/13.
//  Copyright (c) 2013 Aaron Russell. All rights reserved.
//

#import <UIKit/UIKit.h>
#import "TBXML.h"
@interface friendsListTableViewController : UIViewController <UITableViewDataSource, UITableViewDelegate, NSObject>{
    NSMutableArray *friendList;
    TBXML * tbxml;
    IBOutlet UIImage *imageFile;
}
@property (nonatomic, strong) NSMutableArray *_friends;
@property (nonatomic, strong) NSString *lname;

@end

这里是friendsListTableViewController.m文件

//
//  friendsListTableViewController.m
//  @ME
//
//  Created by Aaron Russell on 1/22/13.
//  Copyright (c) 2013 Aaron Russell. All rights reserved.
//

#import "friendsListTableViewController.h"

@interface friendsListTableViewController ()

@end

@implementation friendsListTableViewController


- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

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

- (void)viewDidLoad {
    [super viewDidLoad];

    //USED TO CONNECT TO SERVERS XML
    //    NSData *xmlData = [[NSData alloc]initWithContentsOfURL:[NSURL URLWithString:@"www.soontobesite.com"]];
    //tbxml = [[TBXML alloc]initWithXMLData:xmlData];
    NSString *xmlData = [[NSBundle mainBundle] pathForResource:@"friendlist" ofType:@"xml"];
    NSData *data = [[NSData alloc] initWithContentsOfFile:xmlData];
    tbxml = [[TBXML alloc]initWithXMLData:data];

    //strings
    // Obtain root element
    TBXMLElement * root = tbxml.rootXMLElement;
    if (root)
    {
        TBXMLElement * elem_PLANT = [TBXML childElementNamed:@"friend" parentElement:root];
        while (elem_PLANT !=nil)
        {
            TBXMLElement * elem_BOTANICAL = [TBXML childElementNamed:@"fname" parentElement:elem_PLANT];
            NSString *botanicalName = [TBXML textForElement:elem_BOTANICAL];
            [friendList addObject:botanicalName];
            elem_PLANT = [TBXML nextSiblingNamed:@"friend" searchFromElement:elem_PLANT]; //IF I CALL BREAKPOINT ON THIS LINE THE SIMULATOR BREAKS
        }

        //TBXMLElement *fname = [TBXML childElementNamed:@"fname" parentElement:elem_PLANT];
    }

}


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

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    return [friendList count];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Cell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    // Configure the cell...
    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
    }

    cell.textLabel.text = [friendList objectAtIndex:indexPath.row];

    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 - Table view delegate

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    // Navigation logic may go here. Create and push another view controller.
    /*
     <#DetailViewController#> *detailViewController = [[<#DetailViewController#> alloc] initWithNibName:@"<#Nib name#>" bundle:nil];
     // ...
     // Pass the selected object to the new view controller.
     [self.navigationController pushViewController:detailViewController animated:YES];
     */
}

@end

// // EDIT

我得到了一点，感谢下面的评论中列出的一些建议，然后它不会在numberOfSectionsInTableView或numberOfRowsInSection中断，但现在当我在numberOfSectionsInTableView或numberOfRowsInSection中断，但仍然不是cellForRowAtIndexPath

时它会中断

Answer 1

您忘记分配friendList实例变量。在viewDidLoad的开头（或在初始化程序中更好）执行以下操作：

friendList = [[NSMutableArray alloc] initWithCapacity:0];

如果friendList未初始化，则其值为nil。在Objective-C中向nil发送消息不会使应用程序崩溃，它不会执行任何操作。另请参阅this SO question。

在您的代码中，调用[friendList addObject:botanicalName]根本不执行任何操作。稍后，当您在[friendList count]中调用numberOfRowsInSection时，您将返回0（零）到表视图。由于表视图认为没有行，因此永远不会调用cellForRowAtIndexPath。

我的tableview没有被称为不会在断点崩溃

// // EDIT

1 个答案: