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Why is NSArray empty at the time when UITableView Cell is selected?

开发者 https://www.devze.com 2023-04-09 21:26 出处:网络
I have list of file with some name of friends. I am trying to understand UITableViewNavigation . I load the list from a file but when I select a cell the Data Array at that point seems empty and I can

I have list of file with some name of friends. I am trying to understand UITableViewNavigation . I load the list from a file but when I select a cell the Data Array at that point seems empty and I can not work out why.

At this method I get this error

 - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
    {

        FriendsNameViewController *newView =[[FriendsNameViewController alloc] initWithNibName:@"FriendsNameViewController" bundle:nil];

        [self.navigationController pushViewController:newView animated:YES];
        //Crashes here
        NSString *temp = [dataArray objectAtIndex:indexPath.row];
        NSLog(@"%@",temp);
        [[newView labelx] setText:[NSString stringWithFormat: @"%@" ,temp]];
    }

2011-10-03 14:43:08.411 navman2[69691:b303] * Terminating app due to uncaught exception 'NSRangeException', reason: '* -[NSMutableArray objectAtIndex:]: index 2 beyond bounds for empty array'


Interface

#import <UIKit/UIKit.h>

@interface TableViewController : UITableViewController
{
    NSArray *dataArray;
}

@property(retain,nonatomic) NSArray *dataArray;

@end

and then implementaion here

#import "TableViewController.h"
#import "FriendsNameViewController.h"

@implementation TableViewController
@synthesize dataArray;

- (id)initWithStyle:(UITableViewStyle)style
{
    self = [super initWithStyle:style];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)didReceiveMemoryWarning
{
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];

    // Release any cached data, ima开发者_如何学Goges, etc that aren't in use.
}

#pragma mark - View lifecycle

- (void)viewDidLoad
{
    [super viewDidLoad];

    NSString *filePath = [[NSBundle mainBundle] pathForResource:@"myfriendsList" ofType:@"txt"];
    NSStringEncoding encoding;
    NSError* error;
    NSString* fh = [NSString stringWithContentsOfFile:filePath usedEncoding:&encoding error:&error];
    dataArray = [NSArray alloc];
    dataArray = [fh componentsSeparatedByString:@"\n"];
}

- (void)viewDidUnload
{
    [super viewDidUnload];
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
}

- (void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];
}

- (void)viewWillDisappear:(BOOL)animated
{
    [super viewWillDisappear:animated];
}

- (void)viewDidDisappear:(BOOL)animated
{
    [super viewDidDisappear:animated];
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

#pragma mark - Table view data source

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    // Return the number of sections.
    return 1;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    // Return the number of rows in the section.
    return [dataArray count];
}

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

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
    }

    // Configure the cell...
    cell.textLabel.text = [dataArray objectAtIndex:indexPath.row];

    return cell;
}



#pragma mark - Table view delegate

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{

    FriendsNameViewController *newView =[[FriendsNameViewController alloc] initWithNibName:@"FriendsNameViewController" bundle:nil];

    [self.navigationController pushViewController:newView animated:YES];
    //Crashes here
    NSString *temp = [dataArray objectAtIndex:indexPath.row];
    NSLog(@"%@",temp);
    [[newView labelx] setText:[NSString stringWithFormat: @"%@" ,temp]];
}

@end


If you have verified that the array is correct prior to selecting, then the first thing I would try is to rearrange your code a little bit:

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
    {

        FriendsNameViewController *newView =[[FriendsNameViewController alloc] initWithNibName:@"FriendsNameViewController" bundle:nil];       
        NSString *temp = [dataArray objectAtIndex:indexPath.row];
        NSLog(@"%@",temp);
        [[newView labelx] setText:[NSString stringWithFormat: @"%@" ,temp]];
        [self.navigationController pushViewController:newView animated:YES];
    }
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