初学者:为什么我会得到一个不好的exc接入?[关闭]

我在点击“self.mydata=…”行时遇到异常。

gdb程序接收到信号:exc_bad_access

以下是我的代码:

- (void)viewDidLoad {
    [super viewDidLoad];    
    self.myData = [NSArray arrayWithObjects:
                   [NSArray arrayWithObjects: 
                    @"Boroughs", 
                    [NSArray arrayWithObjects: 
                     @"Kings", 
                     @"Bronx", 
                     @"Manhattan", 
                     @"Queens", 
                     @"Staten Island", 
                     nil], 
                    nil],
                   [NSArray arrayWithObjects: 
                    @"Surrounding Counties", 
                    [NSArray arrayWithObjects: 
                     @"Westchester", 
                     @"Nassau", 
                     @"Suffolk", 
                     "@Fairfield", 
                     nil], 
                    nil],
                   nil];
}