如何删除 NSUserDefaults 中的 NSMutableDictionary 中的对象

Question

我正在尝试从 userdefaults 中的字典中删除一个对象。

NSMutableDictionary *userDefaults = (NSMutableDictionary*)[[NSUserDefaults standardUserDefaults] dictionaryRepresentation];
[userDefaults removeObjectForKey:@"XYZ"];

上面的代码删除了整个字典。

XYZ 是NSMutuableDictionary。我想从 XYZ 中删除一个带有“密码”键的对象。

Answer 1

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSMutableDictionary *dict = [[defaults objectForKey:@"XYZ"] mutableCopy];
[dict removeObjectForKey:@"Password"];
[defaults setObject:dict forKey:@"XYZ"];

Answer 2

应该这样做：

// Access the dictionary you want to edit as a mutable copy
NSMutableDictionary *dict = [[[NSUserDefaults standardUserDefaults] objectForKey:@"dictKey"] mutableCopy];

// Remove the object for the key
[dict removeObjectForKey:@"keyToRemove"];

// Set the dictionary back in user defaults
[[NSUserDefaults standardUserDefaults] setObject:dict forKey:@"dictKey"];

// Save your changes:
// If you need
// In applicationDidEnterBackground: in iOS >= 7.0
// If you are using iOS < 7.0
[[NSUserDefaults standardUserDefaults] synchronize];