iphone : Settings. 包返回空值

Question

我使用的是 xCode 3.2，然后转移到 xCode 4.2 并从 Settings.bundle 中获取一些值......它工作正常。

虽然我需要在 Settings.bundle 中编辑一些值，但 Root.plist 文件没有显示，所以我按照以下步骤操作，但没有对文件进行任何更改。

1) Click on the Settings.Bundle file, go over to the utilities window,
and look in the File Inspector.
2) Using the drop-down, change the file type to 'Application Bundle'

之后我可以看到 Root.plist 但现在无法在应用程序中获取它的值。实际上得到的是 Null 而不是值。

下面是Settings.bundle的代码和图片

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
host = [defaults stringForKey:@"meter_preference"];
if(host == nil)
{
    host = @"10.20.20.1";
    DDLogError(@"Meter host is nil from NSUserDefaults, defaulting to %@", host);
}

Answer 1

我得到了解决方案，只需在 applicationDidFinishLaunchingWithOptions 中调用以下代码来初始化用户默认值。并且有效

将第一行的 somePropertyYouExpect 替换为您在 User Defaults 中存储的属性。

if (![[NSUserDefaults standardUserDefaults] objectForKey:@"somePropertyYouExpect"])  {

    NSString  *mainBundlePath = [[NSBundle mainBundle] bundlePath];
    NSString  *settingsPropertyListPath = [mainBundlePath
                                           stringByAppendingPathComponent:@"Settings.bundle/Root.plist"];

    NSDictionary *settingsPropertyList = [NSDictionary 
                                          dictionaryWithContentsOfFile:settingsPropertyListPath];

    NSMutableArray      *preferenceArray = [settingsPropertyList objectForKey:@"PreferenceSpecifiers"];
    NSMutableDictionary *registerableDictionary = [NSMutableDictionary dictionary];

    for (int i = 0; i < [preferenceArray count]; i++)  { 
        NSString  *key = [[preferenceArray objectAtIndex:i] objectForKey:@"Key"];

        if (key)  {
            id  value = [[preferenceArray objectAtIndex:i] objectForKey:@"DefaultValue"];
            [registerableDictionary setObject:value forKey:key];
        }
    }

    [[NSUserDefaults standardUserDefaults] registerDefaults:registerableDictionary]; 
    [[NSUserDefaults standardUserDefaults] synchronize]; 
}