ios 如何为 NSUserDefault Keys 设置初始值？
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How to set initial values for NSUserDefault Keys?
提问by Suz
I want to set some initial values for my NSUserDefault keys so that the first run of the app has some reasonable initial settings. I thought I ran across a simple way to do this in the app bundle .plist, but now I can't find it. Any ideas?
我想为我的 NSUserDefault 键设置一些初始值，以便应用程序的第一次运行具有一些合理的初始设置。我以为我在应用程序包 .plist 中遇到了一个简单的方法来做到这一点，但现在我找不到它。有任何想法吗？
回答by Ole Begemann
You should use the registerDefaultsmethod of NSUserDefaults. Prepare a plist file in your bundle that contains the default preferences and then use that plist to register the defaults.
您应该使用 的registerDefaults方法NSUserDefaults。在包中准备一个包含默认首选项的 plist 文件，然后使用该 plist 注册默认值。
NSString *defaultPrefsFile = [[NSBundle mainBundle] pathForResource:@"defaultPrefs" ofType:@"plist"];
NSDictionary *defaultPreferences = [NSDictionary dictionaryWithContentsOfFile:defaultPrefsFile];
[[NSUserDefaults standardUserDefaults] registerDefaults:defaultPreferences];
You have to execute this code on every launch of your app. It will add these values to a separate domain in the user defaults hierarchy. Whenever your app's user defaults don't provide a value for a certain key, NSUserDefaultswill fall back to this domain and retrieve the value from there.
您必须在每次启动应用程序时执行此代码。它将这些值添加到用户默认层次结构中的单独域中。每当您的应用程序的用户默认值没有为某个键提供值时，NSUserDefaults就会回退到该域并从那里检索该值。
回答by thanhbinh84
If you have many default values, let use ola's answer, otherwise this is good for a few params
如果您有许多默认值，请使用ola 的答案，否则这对一些参数有好处
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
if (![defaults boolForKey:USERDEFAULT_IS_INITIALIZED]) {
[defaults setBool:YES forKey:USERDEFAULT_IS_INITIALIZED];
// Set initial values
...
[defaults synchronize];
}
回答by James Webster
if ([[[[NSUserDefaults standardUserDefaults] dictionaryRepresentation] allKeys] containsObject:@"initialValuesHaveBeenWritten"])
{
[[NSUserDefaults standardUserDefaults] setValue:obj1 forKey:key1];
[[NSUserDefaults standardUserDefaults] setValue:obj2 forKey:key2];
[[NSUserDefaults standardUserDefaults] setValue:obj1 forKey:@"initialValuesHaveBeenWritten"];
[[NSUserDefaults standardUserDefaults] synchronize];
}
NB: Not tested, done from memory
注意：未经测试，凭记忆完成
回答by Gank
-(void) loadDef
{
NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
_removeAd=[userDefaults boolForKey:SAVE_AD_STATUS];
NSString* strDefSetting=[userDefaults stringForKey:SAVE_STATUS_ADSETTING];
if(strDefSetting==nil
||[strDefSetting isEqualToString:@""]
)
{
strDefSetting=@"0.5";
}
_floatAdmob=strDefSetting.floatValue;//0.5;
}
