0

我有这样的场景，我在 TableViewCell 中使用选择器，如下所示，当我单击视图中的后退按钮时，我想取消该选择器，并将字典作为对象发送到 Selector

我的代码如下

在头文件中

 NSMutableDictionary* photoDict;
 NSMutableDictionary* dictImages;

在 .M 文件中

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    NSString *cellIdentifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
    if(cell==nil)
    {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:cellIdentifier];
        [[NSBundle mainBundle]loadNibNamed:@"MyCellNib" owner:self options:Nil];
        cell = detailChainObj;
    }

    NSString* avatarURL =@"image_Url"; //Any url of image for cell.
    NSString *key =[[NSString alloc] initWithFormat:@"Key%d%d",indexPath.section,indexPath.row];

    dictImages = [NSDictionary dictionaryWithObjectsAndKeys:imageViewCell,@"Img",imgURL,@"imgURL",key,@"key", nil];
    [self performSelectorInBackground:@selector(DownloadLinkzImageOfUser:) withObject:dictImages];


    if([photoDic valueForKey:keyAvt])
    {
        NSData* data = (NSData*)[photoDic valueForKey:key];
        imageViewCell.image = [UIImage imageWithData:data];
    }
    else
    {
        [self performSelectorInBackground:@selector(DownloadImagesForCell:) withObject:dictImages];
    }
}


//

-(void)DownloadImagesForCell:(NSDictionary *)result
{
    UIImageView* img = (UIImageView*)[result objectForKey:@"Img"];
    NSString* urlAvt = [result valueForKey:@"imgURL"];
    if([urlAvt isEqualToString:@"No Image"])
    {
       img.image = [UIImage imageNamed:@"noimg.png"];
    }
    else
    {
       NSData* data = [NSData dataWithContentsOfURL:[NSURL URLWithString:imgURL]];
       img.image = [UIImage imageWithData:data];
       [photoDic setValue:data forKey:[NSString stringWithFormat:@"%@",[result valueForKey:@"key"]]];
    }
 }

现在我想在按下后退按钮时取消这个选择器

请记住，我已经使用过

[NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(DownloadImagesForCell:) object:dictImages];
4

1 回答 1

1

https://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Classes/nsobject_Class/Reference/Reference.html

我猜这个方法只适用于 performSelector:withObject:afterDelay:。

于 2012-07-24T07:01:09.107 回答