objective-c - 如果字典为空，如何使用[NSMutableDictionary dictionaryWithDictionary]？

我从服务器获取一些数据并将其保存到NSDictionary，然后我想使用该NSMutableDictionary初始化NSDictionary。

NSDictionary  * const received = [self serverData];
NSMutableDictionary * const results = [NSMutableDictionary dictionaryWithDictionary:received];

而且，如果我从服务器获取了空的JSON，因此我的NSDictionary将为空，如何使用dictionaryWithDictionary来生成一个空的JSONt_code？我用这个

NSDictionary * const received = [self serverData];
NSMutableDictionary * const results;
if (![received count]) {
    results = [NSMutableDictionary dictionary];
}
else
{
    results = [NSMutableDictionary dictionaryWithDictionary:received];
}

但似乎有代码气味。可能会有更优雅的解决方案？

最佳答案

我会在NSDictionary上创建一个类别，以提供这种安全设置。

+ (NSMutableDictionary *)safeDictionaryWithDictionary:(NSDictionary *)dictionary
{
    return [NSMutableDictionary dictionaryWithDictionary:(dictionary ? dictionary : @{});
}

关于objective-c - 如果字典为空，如何使用[NSMutableDictionary dictionaryWithDictionary]？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/13726704/