網上關于setValue和setObject的區別的文章很多,說的并不準確,首先我們得知道:setObject:ForKey: 是NSMutableDictionary特有的；setValue:ForKey:是KVC的主要方法

話不多說,上代碼:

- (void)viewDidLoad {    [super viewDidLoad];    //setObject和setvalue的區別    NSMutableDictionary *dic = [NSMutableDictionary dictionary];    NSMutableArray *array = [NSMutableArray array];    [array insertObject:@"1" atIndex:0];    [array insertObject:@"2" atIndex:1];        [dic setObject:[NSNull null] forKey:@"haha"];    [dic setObject:[NSNull null] forKey:array];    [dic setObject:[NSNull null] forKey:[NSNull null]];    [dic setObject:@1 forKey:@""];    [dic setObject:@"" forKey:@1];    [dic setObject:nil forKey:@""];    [dic setObject:@"" forKey:nil];    NSLog(@"dic:%@",dic);    //setobject中的key和value可以為除了nil外的任何對象    NSLog(@"*****************");        [dic removeAllObjects];    NSLog(@"dic:%@",dic);        [dic setValue:[NSNull null] forKey:@"haha"];    [dic setValue:[NSNull null] forKey:array];    [dic setValue:[NSNull null] forKey:[NSNull null]];    [dic setValue:@1 forKey:@""];    [dic setValue:@"" forKey:@1];    [dic setValue:nil forKey:@""];    [dic setValue:@"" forKey:nil];    [dic setValue:@"" forKey:@"hehe"];    [dic setValue:array forKey:@""];    NSLog(@"dic2:%@",dic);    //setValue中的KEY只能為字符串 value可以為nil也可以為空對象[NSNull null]    }
程序崩潰,原因就在這幾個警告,由代碼得出以下結論:
setobject中的key和value可以為除了nil外的任何對象
setValue中的key只能為字符串 value可以為nil也可以為空對象[NSNull null]以及全部對象