处理Foundation对象抛出的异常？

Question

我有一个快速的功能来从主要包中获取本地化的应用程序名称localizedInfoDictionary以及一些后备情况.

private func defaultAppName() -> String {
    var name: NSString = ""
    // Check for a localized version of the CFBundleDisplayName
    var mainBundle = NSBundle.mainBundle()
    // EXC_BAD_ACCESS HERE, despite the optional
    var mainBundleInfoDictionary: Dictionary<NSObject, AnyObject>? = mainBundle.localizedInfoDictionary

    if let infoDictionary = mainBundleInfoDictionary {
        name = infoDictionary["CFBundleDisplayName"] as NSString

        if (name.length == 0) {
            name = infoDictionary[kCFBundleNameKey] as NSString
        }
    }

    if (name.length == 0) {
        mainBundleInfoDictionary = mainBundle.infoDictionary

        if let infoDictionary = mainBundleInfoDictionary {
            name = infoDictionary["CFBundleDisplayName"] as NSString

            if (name.length == 0) {
                name = infoDictionary[kCFBundleNameKey] as NSString
            }
        }
    }

    return name
}

我知道这不简洁,但我仍在学习.我看到的问题是访问mainBundle.localizedInfoDictionary没有找到时返回nil,而是抛出一个EXC_BAD_ACCESS.我不能保证在使用此功能的应用程序中会有本地化信息,但处理选项的标准快捷方式在这里不起作用.

我怎样才能捕获NSBundle localizedInfoDictionary调用抛出的异常或调整我的swift代码继续前进？

Answer 1

首先,这是Swift中的一个错误,应该报告给bugreport.apple.com.此方法用于返回隐式可选.他们应该将它转换为显式可选,但是将其转换为非可选,因为该方法可以返回nil:

NSDictionary *mainBundleInfoDictionary = [[NSBundle mainBundle] localizedInfoDictionary];
NSLog(@"%@", mainBundleInfoDictionary);

但是你通常不需要localizedInfoDictionary.你可以直接问NSBundle:

private func defaultAppName() -> String {
  let mainBundle = NSBundle.mainBundle()
  let displayName = mainBundle.objectForInfoDictionaryKey("CFBundleDisplayName") as? String
  let name = mainBundle.objectForInfoDictionaryKey(kCFBundleNameKey) as? String
  return displayName ?? name ?? "Unknown"
}