爲什麼在選擇UITableView單元時NSArray爲空？

Question

我有一些朋友的名字的文件列表。我想了解UITableViewNavigation。我從一個文件加載列表，但是當我選擇一個單元格時，數據數組在那一點上似乎是空的，我無法弄清楚爲什麼。
在該方法我得到這個錯誤

- (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] *終止應用程序由於 未捕獲的異常' NSRangeException'，原因：'* - [NSMutableArray objectAtIndex：]：索引2超出空數組的界限'

---

接口

#import <UIKit/UIKit.h> 

@interface TableViewController : UITableViewController 
{ 
    NSArray *dataArray; 
} 

@property(retain,nonatomic) NSArray *dataArray; 

@end 

然後implementaion這裏

#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, images, 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 

Answer 1

如果您已經驗證該陣列是否選擇之前正確的，那麼我會嘗試的第一件事是重新排列你的代碼一點點：

- (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]; 
    }