从NSUserDefaults字典iOs中删除所有键 [英] Delete all keys from a NSUserDefaults dictionary iOs

问题描述

我使用NSUserDefaults字典存储基本信息，如高分等，以便当用户关闭应用程序数据不丢失。无论如何我使用：

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:

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

来存储数据。如果我想存储一个新的高分，例如，我会这样做：

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

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

以后如果我想检索高分，我会这样做：

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

[prefs integerForKey:@"highScore"];

无论如何，我存储了很多其他东西，因为 NSUserDefaults启用您存储布尔值，整数， code>等等。我需要执行什么方法来删除所有的键，使NSUserDefaults变成像我第一次启动应用程序？

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

我在寻找例如：

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

或者也许有一种方法获取所有的键，我必须循环通过每个对象，不知道如何删除它们。

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.

编辑：

我试过：

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

我仍然可以检索高分....

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

推荐答案

如果您查看了 NSUserDefaults文档，您将看到一个方法 - （NSDictionary *）dictionaryRepresentation 。在标准用户默认值上使用此方法，可以获取用户默认值中的所有键的列表。您可以使用此来清除用户默认值：

If you have a look at the NSUserDefaults documentation you 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:

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

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