Question

我收到EXC_BAD_ACCESS，但我不明白为什么。这是代码：

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

    TDBadgedCell *cell = [[[TDBadgedCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier] autorelease];


    SubscriptionArray * element =[reader.subscriptions objectAtIndex:[indexPath row]];



    [cell.textLabel setText:element.title]; // <--- error at this line of code



    return cell;
}

reader.subscritions是NSMutableArray，包含81个元素（我确定用NSLog验证了）但是当我尝试设置标题时我有这个错误...为什么？ SubscritionArray是一个自定义类，包含3个字符串和1个int。

自定义类：头

#import <Foundation/Foundation.h>

@interface SubscriptionArray : NSObject{
    NSString *title;
    NSString *source;
    NSString *htmlUrl;
    NSInteger count;
}

@property (nonatomic,retain) NSString *title;
@property (nonatomic,retain) NSString *source;
@property (nonatomic,retain) NSString *htmlUrl;
@property (nonatomic) NSInteger count;
@end

实现：

#import "SubscriptionArray.h"

@implementation SubscriptionArray
@synthesize title,source,htmlUrl,count;

-(void)dealloc{
    [title release];
    [source release];
    [htmlUrl release];

}

- (id)initWithCoder:(NSCoder *)decoder {
    if (self = [super init]) {

        title = [[decoder decodeObjectForKey:@"title"] retain];
        source = [[decoder decodeObjectForKey:@"source"] retain];
        htmlUrl = [[decoder decodeObjectForKey:@"htmlUrl"] retain];
        //count = [decoder decodeIntForKey:@"count"];

    }
    return self;
}

- (void)encodeWithCoder:(NSCoder *)encoder {

    if (title) [encoder encodeObject:title forKey:@"title"];
    if (source) [encoder encodeObject:source forKey:@"source"];
    if (htmlUrl) [encoder encodeObject:htmlUrl forKey:@"htmlUrl"];
    //if (count) [encoder encodeInteger:count forKey:@"count"];
}



@end

修改的我是我得到的 * - [__ NSArrayM objectAtIndex：]：发送到解除分配的实例0xe5a8260的消息

这就是我设置NSMutableArray的方式

subscriptions = [[NSMutableArray alloc]init];
    NSArray *paths = NSSearchPathForDirectoriesInDomains
    (NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];


    //make a file name to write the data to using the
    //documents directory:
    NSString *fullFileName = [NSString stringWithFormat:@"%@/subscriptions", documentsDirectory];
    [subscriptions removeAllObjects];
    subscriptions = [NSKeyedUnarchiver unarchiveObjectWithFile:fullFileName];

Answer 1

我冒昧地说你的订阅元素数组与你的行索引不匹配（只是一个猜测）。建议您在声明'element'之后和尝试设置标签之前立即设置调试器断点。您应该能够看到您是否实际获得了一个SubscriptionArray对象...

Answer 2

reader.subscriptions中的可变数组在您尝试在tableView:cellForRowAtIndexPath:中引用之前被取消分配。确保阅读器正确保留或复制subscriptions阵列，并且您不会通过在某处发送额外的release或autorelease消息来过度释放它。从reader实例的类中发布相关代码可能会有所帮助。

包含自定义类的NSMutableArray上的EXC_BAD_ACCESS

2 个答案: