iOS5 上的 NSIndexPath 崩溃答案

【问题标题】：NSIndexPath crash on iOS5iOS5 上的 NSIndexPath 崩溃
【发布时间】：2011-12-10 22:12:24
【问题描述】：

我的应用在 iOS5 之前运行良好。

我有一个包含 2 个部分的分组表视图。每个部分都有 1 个选择，用 UITableViewCellAccessoryCheckmark 显示。

当我尝试确定 if([lastIndexPath1 isEqual:indexPath]) 时，我的应用在 iOS5 中崩溃了

更新：完整的相关代码如下：

lastIndexPath1 和 lastIndexPath2 都是我在标题中声明的 NSIndexPath 对象。编号 1 跟踪第 0 节中的最后一个 indexPath，编号 2 跟踪第 1 节。

- (void)viewDidLoad
{



 [super viewDidLoad];
    self.view.backgroundColor = [UIColor whiteColor];  

//Initialize the array.
listOfItems = [[NSMutableArray alloc] init];

NSArray *fontName = [NSArray arrayWithObjects:@"Baskerville", @"Palatino", @"Times New Roman", @"Verdana", nil];
NSDictionary *fontNameInDict = [NSDictionary dictionaryWithObject:fontName forKey:@"FontOptions"];

NSArray *fontSize = [NSArray arrayWithObjects:@"Der var engang", @"Der var engang", @"Der var engang", @"Der var engang", @"Der var engang", @"Der var engang", @"Der var engang", @"Der var engang", @"Der var engang", @"Der var engang", @"Der var engang", @"Der var engang", nil];
NSDictionary *fontSizeInDict = [NSDictionary dictionaryWithObject:fontSize forKey:@"FontOptions"];

[listOfItems addObject:fontNameInDict];
[listOfItems addObject:fontSizeInDict];


}

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


     NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

    //SET SKRIFTTYPE 
    NSString *neverOpendFonts1 = [prefs objectForKey:@"neverOpendFonts1"];  

    if (![neverOpendFonts1 isEqualToString:@"1"]) {



            lastIndexPath1 = [NSIndexPath indexPathForRow:1 inSection:0];

            UITableViewCell *newCell = [myTableView cellForRowAtIndexPath:lastIndexPath1]; 

            newCell.accessoryType = UITableViewCellAccessoryCheckmark; 

            NSString *lastIndexPathString1 = [NSString stringWithFormat:@"1"];

            [prefs setObject:lastIndexPathString1 forKey:@"lastIndexPath1"];

            NSString *fontName = [NSString stringWithFormat:@"Palatino"];

            [prefs setObject:fontName forKey:@"fontName"];

            neverOpendFonts1 = [NSString stringWithFormat:@"1"];

            [prefs setObject:neverOpendFonts1 forKey:@"neverOpendFonts1"];

            [prefs synchronize];

            NSLog(@"Har aldrig været åbnet - font options"); 


    }

    else
    {
        NSInteger row = [[prefs objectForKey:@"lastIndexPath1"] intValue];

        NSLog(@"FONT ROW: %i", row);

        lastIndexPath1 = [NSIndexPath indexPathForRow:row inSection:0];

        UITableViewCell *newCell = [myTableView cellForRowAtIndexPath:lastIndexPath1]; 

        newCell.accessoryType = UITableViewCellAccessoryCheckmark; 

    }
 //SET SKRIFT STØRRELSE


    NSString *neverOpendFonts2 = [prefs objectForKey:@"neverOpendFonts2"];  

    if (![neverOpendFonts2 isEqualToString:@"1"]) {

        if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
        {

        lastIndexPath2 = [NSIndexPath indexPathForRow:2 inSection:1];

        UITableViewCell *newCell2 = [myTableView cellForRowAtIndexPath:lastIndexPath2]; 

        newCell2.accessoryType = UITableViewCellAccessoryCheckmark; 

        NSString *lastIndexPathString2 = [NSString stringWithFormat:@"2"];

        [prefs setObject:lastIndexPathString2 forKey:@"lastIndexPath2"];

        NSString *fontSize = [NSString stringWithFormat:@"24.0"];  

        [prefs setObject:fontSize forKey:@"fontSize"];

        neverOpendFonts2 = [NSString stringWithFormat:@"1"];

        [prefs setObject:neverOpendFonts2 forKey:@"neverOpendFonts2"];

        [prefs synchronize];

        }

        else {

            lastIndexPath2 = [NSIndexPath indexPathForRow:0 inSection:1];

            UITableViewCell *newCell3 = [myTableView cellForRowAtIndexPath:lastIndexPath2]; 

            newCell3.accessoryType = UITableViewCellAccessoryCheckmark; 

            NSString *lastIndexPathString2 = [NSString stringWithFormat:@"0"];

            [prefs setObject:lastIndexPathString2 forKey:@"lastIndexPath2"];

            NSString *fontSize = [NSString stringWithFormat:@"16.0"];  

            [prefs setObject:fontSize forKey:@"fontSize"];

            neverOpendFonts2 = [NSString stringWithFormat:@"1"];

            [prefs setObject:neverOpendFonts2 forKey:@"neverOpendFonts2"];

            [prefs synchronize];
        }

    }

    else
    {

        NSInteger row2 = [[prefs objectForKey:@"lastIndexPath2"] intValue];

        NSLog(@"FONTSIZE ROW: %i", row2);

       lastIndexPath2 = [NSIndexPath indexPathForRow:row2 inSection:1];

        UITableViewCell *newCell2 = [myTableView cellForRowAtIndexPath:lastIndexPath2]; 

        newCell2.accessoryType = UITableViewCellAccessoryCheckmark; 


    }

    [myTableView reloadData];

}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    //Number of rows it should expect should be based on the section
    NSDictionary *dictionary = [listOfItems objectAtIndex:section];
    NSArray *array = [dictionary objectForKey:@"FontOptions"];
    return [array count];
}

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {

    return [listOfItems count];
}

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


    static NSString *CellIdentifier = @"Cell";

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

    // Set up the cell...

    //First get the dictionary object
    NSDictionary *dictionary = [listOfItems objectAtIndex:indexPath.section];
    NSArray *array = [dictionary objectForKey:@"FontOptions"];
    NSString *cellValue = [array objectAtIndex:indexPath.row];
    cell.textLabel.text = cellValue;


    if (indexPath.section == 0)
    {

        if([lastIndexPath1 isEqual:indexPath])
        {
            cell.accessoryType = UITableViewCellAccessoryCheckmark;
        }
        else 
        {
            cell.accessoryType = UITableViewCellAccessoryNone;
        }

        switch (indexPath.row) {
            case 0:
            {
             cell.textLabel.font = [UIFont fontWithName:@"Baskerville" size:24];   
            }
                break;
            case 1:
            {
              cell.textLabel.font = [UIFont fontWithName:@"Palatino" size:24];    
            }
                break;
            case 2:
            {
                cell.textLabel.font = [UIFont fontWithName:@"Times New Roman" size:24];  
            }
                break;
            case 3:
            {
               cell.textLabel.font = [UIFont fontWithName:@"Verdana" size:24];   
            }
                break;
        }

    }
    if (indexPath.section == 1) {


        if([lastIndexPath2 isEqual:indexPath])
        {
            cell.accessoryType = UITableViewCellAccessoryCheckmark;
        }
        else 
        {
            cell.accessoryType = UITableViewCellAccessoryNone;
        }

        switch (indexPath.row) {
            case 0:
            {
                cell.textLabel.font = [UIFont fontWithName:@"Palatino" size:16];   
            }
                break;
            case 1:
            {
                cell.textLabel.font = [UIFont fontWithName:@"Palatino" size:20];    
            }
                break;
            case 2:
            {
                cell.textLabel.font = [UIFont fontWithName:@"Palatino" size:24];  
            }
                break;
            case 3:
            {
                cell.textLabel.font = [UIFont fontWithName:@"Palatino" size:28];   
            }
                break;
            case 4:
            {
                cell.textLabel.font = [UIFont fontWithName:@"Palatino" size:32];   
            }
                break;
            case 5:
            {
                cell.textLabel.font = [UIFont fontWithName:@"Palatino" size:36];   
            }
                break;
            case 6:
            {
                cell.textLabel.font = [UIFont fontWithName:@"Palatino" size:40];   
            }
                break;
            case 7:
            {
                cell.textLabel.font = [UIFont fontWithName:@"Palatino" size:44];   
            }
                break;
            case 8:
            {
                cell.textLabel.font = [UIFont fontWithName:@"Palatino" size:48];   
            }
                break;
            case 9:
            {
                cell.textLabel.font = [UIFont fontWithName:@"Palatino" size:52];   
            }
                break;
            case 10:
            {
                cell.textLabel.font = [UIFont fontWithName:@"Palatino" size:56];   
            }
                break;
            case 11:
            {
                cell.textLabel.font = [UIFont fontWithName:@"Palatino" size:60];   
            }
                break;
        }


        }


        return cell;
}

【问题讨论】：

控制台是否告诉您有关错误的任何信息？或者，至少，错误是 SIGABRT 还是 EXC_BAD_ACCESS？
是的，我得到了 EXC_BAD_ACCESS。抱歉不清楚...如果我注释掉 if([lastIndexPath1 isEqual:indexPath]) 函数，应用程序运行正常...
您在哪里进行比较以及如何存储值？
我在做比较： - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath... 如果我用整数设置值我也会得到错误.只有iOS5有问题
lastIndexPath1 是如何定义的，有哪些属性？您可以尝试在整个课程中都使用 self.lastIndexPath1 吗？

标签： iphone ipad uitableview ios5

【解决方案1】：

lastIndexPath1 是如何定义的，具有哪些属性？您可以尝试在整个课程中都使用 self.lastIndexPath1 吗？

【讨论】：

就像richerd 评论的那样，问题的根源在于保留对象。 self.indexPath = ... 如果属性标记为“保留”，请确保调用保留设置器 - 如果是非属性，您应该自己保留/释放
我在 iOS 5.0 上支持应用程序时遇到了同样的问题，谢谢大家。

【解决方案2】：

您没有保留最后一个索引路径。

    lastIndexPath1 = [NSIndexPath indexPathForRow:row inSection:0];

[NSIndexPath indexPathforRow:row inSection:0] 返回一个自动释放的对象，在下一个事件循环结束时，如果它没有保留则释放。

试试

[[NSIndexPath indexPathForRow:row inSection:0] retain];

我假设您没有在 Xcode 4 和 ARC 下编译

您确实应该使用属性访问器来处理 lastIndexPath1 变量的内存管理

@property (nonatomic, retain) NSIndexPath lastIndexPath1;

然后@synthesize lastIndexPath1;

每当您分配 lastIndexPath 时，请使用 self.lastIndexPath = [NSIndexPath ....]

【讨论】：