我有如下代码。我正在从 Web 服务器检索 JSON。
AFJSONRequestOperation *operation = [AFJSONRequestOperation JSONRequestOperationWithRequest:request success:^(NSURLRequest *request, NSHTTPURLResponse *response, id JSON)
{
for (NSMutableDictionary * dataDict in JSON) {
if ([dataDict objectForKey:@"userPicture"])
{
objectForKey:@"userPicture"]);
NSURL *url = [NSURL URLWithString:[dataDict objectForKey:@"userPicture"]];
UIImage *image = [UIImage imageWithData: [NSData dataWithContentsOfURL:url]];
[dataDict setValue:@"userPicture"
forKey:@"userPicture"];
}
[messageList addObject: dataDict];
}
[self processComplete];
}
failure:^(NSURLRequest *request , NSURLResponse *response , NSError *error , id JSON)
{
NSLog(@"Failed: %@", error);
}];
但是它崩溃并出现以下错误:
*** 由于未捕获的异常“NSInternalInconsistencyException”而终止应用程序,原因:“-[__NSCFDictionary setObject:forKey:]: mutating method sent to immutable object”
现在,我没有得到的是,我正在尝试setValue:forKey
在 dataDict 中,它是实例化NSMutableDictionary
的,所以我应该能够设置值。