NSUserDefaults数据保存报错：Attempt to set a non-property-list object...

在使用NSUserDefaults的时候插入数据有时候会报以下错误：

Attempt to set a non-property-list object <CFBasicHash 0x7f9c1a5cce80 [0x11192c7b0]>{type = immutable dict, count = 27,
entries =>
 3 : ext_attr = <CFString 0x110446380 [0x11192c7b0]>{contents = ""}
 4 : zhicheng = <CFString 0x110446380 [0x11192c7b0]>{contents = ""}
 5 : code = <CFString 0x7f9c1a54e900 [0x11192c7b0]>{contents = "YS1000000000011"}
 6 : zhuzhi = <CFString 0x110446380 [0x11192c7b0]>{contents = ""}
 10 : sex = <CFString 0x110446380 [0x11192c7b0]>{contents = ""}
 14 : cat_id = <CFString 0x110446380 [0x11192c7b0]>{contents = ""}
 15 : pass = 123123
 16 : keshi = <CFNull 0x11192caf0 [0x11192c7b0]>
 18 : name = <CFString 0x7f9c1a566740 [0x11192c7b0]>{contents = "新医生"}
 19 : sp = <CFString 0x110446380 [0x11192c7b0]>{contents = ""}
 20 : moreinfo = <CFString 0x110446380 [0x11192c7b0]>{contents = ""}
 21 : state = <CFString 0x110446380 [0x11192c7b0]>{contents = ""}
 22 : <CFString 0x7f9c1a564dc0 [0x11192c7b0]>{contents = "comment_num"} = 0
 23 : id = 11
 25 : p_attr = <CFString 0x110446380 [0x11192c7b0]>{contents = ""}
 26 : pcolumn = 1
 27 : pic = <CFString 0x7f9c1a56d330 [0x11192c7b0]>{contents = "http://58.61.37.228:3080/td_yisheng/static/img/photo.gif"}
 28 : <CFString 0x7f9c1a5165f0 [0x11192c7b0]>{contents = "zhizhaopic"} = <CFString 0x110446380 [0x11192c7b0]>{contents = ""}
 29 : mobile = <CFString 0x7f9c1c8f8ee0 [0x11192c7b0]>{contents = "18682355562"}
 30 : showtpl = 1
 31 : email = <CFString 0x110446380 [0x11192c7b0]>{contents = ""}
 32 : area = <CFString 0x7f9c1c8f3ba0 [0x11192c7b0]>{contents = "区域"}
 33 : uptime = <CFArray 0x7f9c1a5ceff0 [0x11192c7b0]>{type = immutable, count = 1, values = (
 0 : <CFString 0x110446380 [0x11192c7b0]>{contents = ""}
)}
 36 : price = <CFBasicHash 0x7f9c1c8e3080 [0x11192c7b0]>{type = immutable dict, count = 5,
entries =>
 2 : baoyue = 1
 3 : dianhua = 1
 4 : huizhen = 1
 5 : yuyue = 1
 6 : zixun = 1
}

 38 : <CFString 0x7f9c1c8e2c60 [0x11192c7b0]>{contents = "comment_rank"} = 5
 39 : regtime = <CFString 0x7f9c1c8fb2b0 [0x11192c7b0]>{contents = "1442394762"}
 40 : patchcode = <CFString 0x110446380 [0x11192c7b0]>{contents = ""}
}
 as an NSUserDefaults/CFPreferences value for key UserModelDic

这种错误的原因是插入了不识别的数据类型，NSUserDefaults支持的数据类型有 NSString、 NSNumber、NSDate、 NSArray、NSDictionary 、BOOL、NSInteger、NSFloat等系统定义的数据类型。

自定义的类型需要转成NSData再存入。

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我原来认为NSUserDefaults存不了数组，又换成了字典，但是还是报错，最后求助网友大神解决了，是我里边的数据结构有"<null>"，而NSUserDefaults是不能被成功解析并存入的，所有在存入之前需要将里边的"<null>"改成""即可。