Attempt to set a non-property-list object as an NSUserDefaults

当使用NSUserDefault直接存储Facebook的token对象时，会报错（Attempt to set a non-property-list object as an NSUserDefaults），因为NSUserDefault无法直接存储自定义对象。

解决方法为：

1、存储对象

[cpp]  view plain copy

 NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
 NSData *tokenObject = [NSKeyedArchiver archivedDataWithRootObject:token];
 [userDefaults setObject:tokenObject forKey:@"FBToken"];
  [userDefaults synchronize];

2、读取对象

[cpp]  view plain copy

 NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
 NSData *tokenObject = [userDefaults objectForKey:@"FBToken"];
 FBSDKAccessToken * token = [NSKeyedUnarchiver unarchiveObjectWithData:tokenObject];

参考资料：

http://stackoverflow.com/questions/19720611/attempt-to-set-a-non-property-list-object-as-an-nsuserdefaults

http://blog.csdn.net/chyroger/article/details/5785297（实现原理以及如何实现存储自定义对象