使用数据管理单例

这是我的单例代码(相当于样板文件):

@interface DataManager : NSObject {
    NSMutableArray *eventList;
}

@property (nonatomic, retain) NSMutableArray *eventList;

+(DataManager*)sharedDataManager;

@end

然后是.m:

#import "DataManager.h"

static DataManager *singletonDataManager = nil;

@implementation DataManager

@synthesize eventList;

+(DataManager*)sharedDataManager {
    @synchronized(self) {
        if (!singletonDataManager) {
            singletonDataManager = [[DataManager alloc] init];
        }
    }
    NSLog(@"Pulling a copy of shared manager.");
    return singletonDataManager;
}

因此,在我的AppDelegate中,我在启动第一个视图之前加载了一些内容:

NSMutableArray *eventList = [DataManager sharedDataManager].eventList;

....

NSLog(@"Adding event %@ to eventList", event.title);
[eventList addObject:event];
NSLog(@"eventList now has %d members", [eventList count]);
[event release];

如你所见,我已经在代码中添加了nslog对自己的爱注释。日志的输出如下:

2010-05-10 09:08:53.355 MyApp[2037:207] Adding event Woofstock Music Festival to eventList
2010-05-10 09:08:53.355 MyApp[2037:207] eventList now has 0 members
2010-05-10 09:08:53.411 MyApp[2037:207] Adding event Test Event for Staging to eventList
2010-05-10 09:08:53.411 MyApp[2037:207] eventList now has 0 members
2010-05-10 09:08:53.467 MyApp[2037:207] Adding event Montgomery Event to eventList
2010-05-10 09:08:53.467 MyApp[2037:207] eventList now has 0 members
2010-05-10 09:08:53.524 MyApp[2037:207] Adding event Alamance County Event For June to eventList
2010-05-10 09:08:53.524 MyApp[2037:207] eventList now has 0 members

…给出了什么?我没有错误进入我的事件列表NSmutableArray。但是我加了一句:无声地失败了?