ios - TableView insertRowsAtIndexPath 崩溃

Question

我的应用程序运行良好，我没有将其修改为具有专用的数据 Controller 类，而不是像在初始测试期间那样在主 UI 类中处理数据。然而，自从更改以来，当向 TableView 添加新项目时，它不断崩溃。

崩溃的代码行和错误是；

[self.tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];

2012-07-22 07:17:44.772 speecher[1897:707] * Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'attempt to insert row 0 into section 0, but there are only 0 rows in section 0 after the update'

该类(主 MasterViewController 类)的完整代码如下。

//
//  SpeecherMasterViewController.m
//  speecher
//
//

#import "SpeecherMasterViewController.h"
#import "SpeecherDataController.h"
#import "SpeecherDetailViewController.h"

@interface SpeecherMasterViewController () {

    NSString *newTitle;
    NSMutableArray *_speeches;
    NSMutableArray *_content;
    SpeecherDataController *object;

}
@end

@implementation SpeecherMasterViewController

@synthesize detailViewController = _detailViewController;

- (void)awakeFromNib
{
    self.clearsSelectionOnViewWillAppear = NO;
    self.contentSizeForViewInPopover = CGSizeMake(320.0, 600.0);
    [super awakeFromNib];
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    self.navigationItem.leftBarButtonItem = self.editButtonItem;

    UIBarButtonItem *addButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:self action:@selector(insertNewObject:)];
    self.navigationItem.rightBarButtonItem = addButton;
    self.detailViewController = (SpeecherDetailViewController *)[[self.splitViewController.viewControllers lastObject] topViewController];
    object = [[SpeecherDataController alloc] init];
}

- (void)viewDidUnload
{
    [super viewDidUnload];
    // Release any retained subviews of the main view.
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return YES;
}


#pragma mark - Table View

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

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

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cell"];
    cell.textLabel.text = [object returnTitle:indexPath.row];
    return cell;
}

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

- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
    if (editingStyle == UITableViewCellEditingStyleDelete) {
        [_speeches removeObjectAtIndex:indexPath.row];
        [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject: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;
}
*/

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


    NSString *titleobj = [object returnTitle:indexPath.row];
    NSString *contentobj = [object returnContent:indexPath.row];
    self.detailViewController.detailItem = titleobj;
    self.detailViewController.detaitContent = contentobj;
}



- (void)insertNewObject:(id)sender
{
    //Make sure clear before we start, also make sure initalized (double redundancy with clear statement at end)
    newTitle = @"";

    //New Title pop up UIAlert View
    UIAlertView * alert = [[UIAlertView alloc] 
                           initWithTitle:@"New Speech" 
                           message:@"Please enter a name for speech" 
                           delegate:self 
                           cancelButtonTitle:@"Create" 
                           otherButtonTitles:nil];

    alert.alertViewStyle = UIAlertViewStylePlainTextInput;

    UITextField * alertTextField = [alert textFieldAtIndex:0];

    alertTextField.keyboardType = UIKeyboardTypeDefault;

    alertTextField.placeholder = @"Enter a new title";
    [alert show];


}



- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{ 
    newTitle = [[alertView textFieldAtIndex:0] text];

    [object addNewContent:newTitle :@"IT REALLY WORKS!" :@"Nothing"];

        //create new speech title, add to array and add to tableview
    NSIndexPath *indexPath = [NSIndexPath indexPathForRow:0 inSection:0];
    [self.tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];

    //Clear newTitle for use next time
    newTitle = @"";

}

@end

编辑:

根据注释修改添加[object addNewContent]方法和类，

//
//  SpeecherDataController.m
//  speecher
//
//

#import "SpeecherDataController.h"

@interface SpeecherDataController ()
{
    NSMutableArray *titles;
    NSMutableArray *content;
    NSMutableArray *timer;
}
@end

@implementation SpeecherDataController

-(void) addNewContent:(NSString*)sTitle : (NSString*)sContent :(NSString*)sTimer
{
    [titles insertObject:sTitle atIndex:0];
    [content insertObject:sContent atIndex:0];
    [timer insertObject:sTimer atIndex:0];
}


//Methods to return data
-(NSString*) returnTitle:(NSUInteger)row
{
    return [titles objectAtIndex:row];
}

-(NSString*) returnContent:(NSUInteger)row
{
    return [content objectAtIndex:row];
}

-(NSString*) returnTimer:(NSUInteger)row
{
    return [timer objectAtIndex:row];
}

-(NSInteger) returnNoObjects
{
    return titles.count;
}



@end

Answer 1

问题是 NSMutableArrays 尚未分配和初始化。必须添加检查以查看它们是否有 init，如果没有则进行分配。新支票看起来像这样，

-(void) addNewContent:(NSString*)sTitle : (NSString*)sContent :(NSString*)sTimer
{

    if(!titles)
    {
        titles = [[NSMutableArray alloc] init];
    }
    if(!content)
    {
        content = [[NSMutableArray alloc] init];
    }
    if(!timer)
    {
        timer = [[NSMutableArray alloc] init];
    }

    [titles insertObject:sTitle atIndex:0];
    [content insertObject:sContent atIndex:0];
    [timer insertObject:sTimer atIndex:0];
}