[NSDictionaryI setObject:forKey:]:发送到实例的选择器无法识别

Question

我获取JSON数据并将其存储在"NSUserDefaults"中，然后我试图检索该数据以从字典中添加或删除对象，但我得到了错误

无法识别的选择器发送到实例

添加到NSMutableDictionary时

// new dict
NSMutableDictionary *userTranslations = [NSMutableDictionary new];
for (NSString *key in keys) {
[userTranslations setObject:dicky[key] forKey:key];
};
// then add that dictionary as the key for uid
[artworkTranslations setObject:userTranslations forKey:uid];

JSON数据

{
people =     {
"title" = "Hello";
"details" = "Amet justo donec enim diam vulputate.<br><br>Ut etiam sit amet nisl. Mattis vulputate enim nulla aliquet porttitor.<br><br>Euismod quis viverra nibh cras pulvinar mattis nunc sed blandit. Dis parturient montes nascetur ridiculus mus.";
};
}

NSUserDefaults

Objects: {
9ddfdd2d652c742 = {
first =     {
"title" = "Hello";
"details" = "Amet justo donec enim diam vulputate.<br><br>Ut etiam sit amet nisl. Mattis vulputate enim nulla aliquet porttitor.<br><br>Euismod quis viverra nibh cras pulvinar mattis nunc sed blandit. Dis parturient montes nascetur ridiculus mus.";
};
};
}

完整代码

NSDictionary * jsonData = [data objectForKey:@"people"];
if (jsonData) {
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSMutableDictionary *objects = [defaults objectForKey:@"Objects"];
NSArray *keys = [jsonData allKeys];
if (objects) {
// get people from UD
NSMutableDictionary *people = [objects objectForKey:uid];
if (people) {
NSLog(@"there ARE in people in dictionary from UD");
//get uid of person key and if exists then remove
[objects removeObjectForKey:uid]; // error here
// new dict
NSMutableDictionary *user = [NSMutableDictionary new];
for (NSString *key in keys) {
[users setObject:jsonData[key] forKey:key]; // Crash Here
};
// then add that dictionary as the key for uid
[people setObject:user forKey:uid];
} else {
NSLog(@"NO people dictionary in objects from UD");
NSMutableDictionary *users = [NSMutableDictionary new];
NSMutableDictionary *people = [NSMutableDictionary new];
for (id key in keys) {
NSMutableDictionary *person = [jsonData objectForKey:key];
[people setObject:person forKey:key]; // Crash here
};
[user setObject:people forKey:uid];
[objects setObject:users forKey:uid];
[defaults setObject:objects forKey:@"Objects"];
}
[defaults synchronize];
} else if (!objects){
NSLog(@"People NOT FOUND in UserDefaults");
NSMutableDictionary *people = [NSMutableDictionary new];
NSMutableDictionary *user = [NSMutableDictionary new];
for (NSString *key in keys) {
[users setObject:jsonData[key] forKey:key];
};
[people setObject:user forKey:uid];
[defaults setObject:people forKey:@"Objects"];
[defaults synchronize];
}
}

Answer 1

您的问题迫在眉睫：

NSMutableDictionary *objects = [defaults objectForKey:@"Objects"];

您无法从用户默认值中获取可变集合。你需要使它可变：

NSMutableDictionary *objects = [[defaults objectForKey:@"Objects"] mutableCopy];

还要记住，objects在应用程序第一次运行时将为空。所以也要考虑到这一点。