Question

我有UITableViewController，它有类似按钮的推文。我正在做的是当点击按钮时，如果成功尝试更新类似的计数+ 1，我做了所有上述方法，除了更新部分。我得到Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: '-[__NSCFDictionary setObject:forKey:]: mutating method sent to immutable object'错误。

这是我的代码。

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
    FeedTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cell" forIndexPath:indexPath];


    NSDictionary *feedList = [liveFeeds objectAtIndex:indexPath.row];
//liveFeeds is NSMutableArray

cell.likeCount.text = [feedList objectForKey:@"likes"];
cell.like.tag = indexPath.row;

    [cell.like addTarget:self action:@selector(likeClicked:) forControlEvents:UIControlEventTouchUpInside];
}

-(void) likeClicked:(UIButton*)sender{

//Here im using AFNetworking and getting JSON response.
//After that im doing following to update the like

NSMutableDictionary* feedList = [liveFeeds objectAtIndex:sender.tag];

            NSString *oldLike = [feedList objectForKey:@"likes"];
            int newLike = [oldLike intValue] + 1;
            NSString *strFromInt = [NSString stringWithFormat:@"%d",newLike];

            NSLog(@"updated like %@",strFromInt); // up to this it works

            [feedList setObject:strFromInt forKey:@"likes"]; // in here it get crashe

            [self.tableView reloadData];

}

我想做的是。 liveFeeds数组更新使用Like Like并重新加载表。我做错了吗？或者有什么简单的方法可以做到这一点吗？

Answer 1

最有可能[liveFeeds objectAtIndex:sender.tag]是NSDictionary，而非NSMutableDictionary。所以你不能改变它的内容。

构建包含[liveFeeds objectAtIndex:sender.tag]：

内容的Feed列表

NSMutableDictionary* feedlist = [NSMutableDictionary dictionaryWithDictionary:[liveFeeds objectAtIndex:sender.tag]]

Answer 2

我还没有尝试过，但我想你正试图在NSDictionary上使用NSMutableDictionary方法。尝试更改：

NSMutableDictionary* feedList = [liveFeeds objectAtIndex:sender.tag];

要：

NSDictionary* dic = [liveFeeds objectAtIndex:sender.tag]; NSMutableDictionary* feedList = [NSMutableDictionary alloc] initWithDictionary:dic]];

Answer 3

只需创建NSDictionary的可变副本。实际上NSMutableDictionary* feedList = [liveFeeds objectAtIndex:sender.tag]会返回NSDictionary。因此，为了使其可编辑，您必须使用mutableCopy创建另一个可变的副本。 NSMutableDictionary* feedList = [[liveFeeds objectAtIndex:sender.tag]mutableCopy]

 -(void) likeClicked:(UIButton*)sender{

 //Here im using AFNetworking and getting JSON response.
 //After that im doing following to update the like

       NSMutableDictionary* feedList = [[liveFeeds objectAtIndex:sender.tag]mutableCopy];

        NSString *oldLike = [feedList objectForKey:@"likes"];
        int newLike = [oldLike intValue] + 1;
        NSString *strFromInt = [NSString stringWithFormat:@"%d",newLike];

        NSLog(@"updated like %@",strFromInt); // up to this it works

        [feedList setObject:strFromInt forKey:@"likes"]; // in here it get crashe

        [self.tableView reloadData];

 }

UITableViewCell - 更新NSMutableDictionary值

3 个答案: