在NSUserDefaults中保存id类型对象

Question

我想在NSUserDefaults中保存id类型对象值。

-(IBAction)sendOrderReady:(id)sender
{
NSUserDefaults *d = [NSUserDefaults standardUserDefaults];
[d setValue:sender forKey:@"sender"];
// [d setObject:sender forKey:@"sender"];
[d synchronize];
}

Answer 1

来自NSUserDefaults类描述

The NSUserDefaults class provides convenience methods for accessing common types such as floats, doubles, integers, Booleans, and URLs. A default object must be a property list, that is, an instance of (or for collections a combination of instances of): NSData, NSString, NSNumber, NSDate, NSArray, or NSDictionary. If you want to store any other type of object, you should typically archive it to create an instance of NSData.

因此，如果您的ID对象不是上述任何一个实例，那么您必须将其转换为其中一个，this question is what exactly you're looking for.

Answer 2

使用NSUserDefaults，您可以保存以下类类型中的对象：

NSData，NSString，NSNumber，NSDate，NSArray，NSDictionary

如果要存储任何其他类型的对象，则需要将其存档或将其包装在NSData的实例中

Answer 3

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

// saving an NSString
[prefs setObject:@"iPhone" forKey:@"keyToLookupString"];

// saving an NSInteger
[prefs setInteger:442 forKey:@"integerKey"];

// saving a Double
[prefs setDouble:5.15 forKey:@"doubleKey"];

// saving a Float
[prefs setFloat:123.45678 forKey:@"floatKey"];

// This is suggested to synch prefs, but it is not needed
[prefs synchronize];