从 NSUserDefaults 字典 iOS 中删除所有键

Delete all keys from a NSUserDefaults dictionary iOS

提问by Tono Nam

I use the NSUserDefaults dictionary to store basic information such as high scores etc so that when the user closes the app data is not lost. Anyways I use:

我使用 NSUserDefaults 字典来存储基本信息，例如高分等，以便在用户关闭应用程序时不会丢失数据。无论如何我使用：

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

to store data. If I wish to store a new high score for example then I would do:

来存储数据。例如，如果我想存储一个新的高分，那么我会这样做：

[prefs setInteger:1023 forKey:@"highScore"];
[prefs synchronize];  //this is needed in case the app is closed. 

and later if I wish to retrieve the high score I would do:

后来如果我想检索高分，我会这样做：

[prefs integerForKey:@"highScore"];

anyways the point is that I store a lot of other things because the NSUserDefaults enableyou to store booleans, integers, objectsetc. what method would I have to execute to delete all keys so that NSUserDefaults becomes like the fist time I launch the app?

反正问题是，我储存很多其他的事情，因为NSUserDefaults enable你到店里booleans，integers，objects等我有什么方法来执行删除所有键，以便成为NSUserDefaults的像拳头时我启动应用程序？

I am looking for something like:

我正在寻找类似的东西：

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
[prefs deleteAllKeysAndObjectsInTheDictionary];

or maybe there is a way of getting all keys and I have to loop through each object but I don't know how to remove them.

或者也许有一种获取所有键的方法，我必须遍历每个对象，但我不知道如何删除它们。

EDIT:

编辑：

I have tried :

我试过了 ：

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
[NSUserDefaults resetStandardUserDefaults];
[prefs synchronize];

and I still am able to retrieve a high score....

我仍然能够检索到高分....

回答by Alex Nichol

If you have a look at the NSUserDefaults documentationyou will see a method - (NSDictionary *) dictionaryRepresentation. Using this method on the standard user defaults, you can get a list of all keys in the user defaults. You can then use this to clear the user defaults:

如果您查看NSUserDefaults 文档，您将看到一个方法- (NSDictionary *) dictionaryRepresentation。在标准用户默认设置上使用此方法，您可以获得用户默认设置中所有键的列表。然后，您可以使用它来清除用户默认值：

- (void)resetDefaults {
    NSUserDefaults * defs = [NSUserDefaults standardUserDefaults];
    NSDictionary * dict = [defs dictionaryRepresentation];
    for (id key in dict) {
        [defs removeObjectForKey:key];
    }
    [defs synchronize];
}

回答by skywinder

Shortest way to do this with the same resultslike in Alex Nichol's top answer:

使用与Alex Nichol 的最佳答案相同的结果来执行此操作的最短方法：

NSString *appDomain = NSBundle.mainBundle.bundleIdentifier;
[[NSUserDefaults standardUserDefaults] removePersistentDomainForName:appDomain];
[[NSUserDefaults standardUserDefaults] synchronize];

回答by Cameron E

One-liner:

单线：

[[NSUserDefaults standardUserDefaults] removePersistentDomainForName:NSBundle.mainBundle.bundleIdentifier];

回答by Sourabh Sharma

Simple Solution

简单的解决方案

Objective C:

目标 C：

NSString *appDomain = [[NSBundle mainBundle] bundleIdentifier];
[[NSUserDefaults standardUserDefaults] removePersistentDomainForName:appDomain];

In Swift 3.0 :

在Swift 3.0 中：

if let appDomain = Bundle.main.bundleIdentifier {
    UserDefaults.standard.removePersistentDomain(forName: appDomain)
}

回答by superarts.org

Swift version:

迅捷版：

if let bid = NSBundle.mainBundle().bundleIdentifier {
    NSUserDefaults.standardUserDefaults().removePersistentDomainForName(bid)
}   

回答by superarts.org

+ (void) resetStandardUserDefaultsdoesn't persist the changes, it simply resets the in-memory user defaults object so that the next synchronizecall will read from the on-disk copy, instead of overwriting existing in-memory values with the on-disk versions.

+ (void) resetStandardUserDefaults不保留更改，它只是重置内存中用户默认对象，以便下一次synchronize调用将从磁盘副本中读取，而不是用磁盘版本覆盖现有的内存中值。

Iterating over the keys is better, but there's actually a function that does this for you: removePersistentDomainForName:.

迭代键更好，但实际上有一个函数可以为您执行此操作：removePersistentDomainForName:.

// you can usually get the domain via [[NSBundle mainBundle] bundleIdentifier]
[[NSUserDefaults standardUserDefaults]
 removePersistentDomainForName:[[NSBundle mainBundle] bundleIdentifier]];
// or use a string for any other settings domains you use
//[[NSUserDefaults standardUserDefaults]
// removePersistentDomainForName:@"com.mycompany.myappname"];
[[NSUserDefaults standardUserDefaults] synchronize];

At the end of the synchronizeoperation, both the disk and memory copies of user defaults will contain none of the values set by your application.

在synchronize操作结束时，用户默认值的磁盘和内存副本都将不包含应用程序设置的任何值。

回答by netshark1000

Oneliner in Swift:

Swift 中的 Oneliner：

Swift 3

斯威夫特 3

NSUserDefaults.standardUserDefaults().removePersistentDomainForName(
NSBundle.mainBundle().bundleIdentifier!)

Swift 4

斯威夫特 4

UserDefaults.standard.removePersistentDomain(forName: Bundle.main.bundleIdentifier!)

回答by bogen

For those of you that want to do this in the test target, use this (as the removePersistentDomaindoes not work for that case)

对于那些想要在测试目标中执行此操作的人，请使用它（因为removePersistentDomain不适用于这种情况）

Swift 3:

斯威夫特 3：

for key in Array(UserDefaults.standard.dictionaryRepresentation().keys) {
     UserDefaults.standard.removeObject(forKey: key)
}

回答by Taichi Kato

For Swift 3:

对于 Swift 3：

let appDomain = Bundle.main.bundleIdentifier!
UserDefaults.standard.removePersistentDomain(forName: appDomain)

回答by Jay Mehta

For Swift 3:

对于 Swift 3：

if let bundle = Bundle.main.bundleIdentifier {
    UserDefaults.standard.removePersistentDomain(forName: bundle)
}