我正在尝试实现一个类似于 facebook 或 twitter 时间线的表格。但是当我滚动 UITableView
时,它非常缓慢且滞后。我该如何解决这个问题?
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
ViewControllerCell *cell = [tableView dequeueReusableCellWithIdentifier:@"htrcell"];
if (cell==nil)
{
NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"Cell" owner:self options:nil];
cell = [nib objectAtIndex:0];
}
NSDictionary *dataArray = [self.threndsArray objectAtIndex:indexPath.row];
NSURL *url = [NSURL URLWithString:[dataArray objectForKey:@"pic_timeline"]];
NSData *imgData = [NSData dataWithContentsOfURL:url];
cell.upload_image.image =[UIImage imageWithData:imgData];
NSURL *urlimage = [NSURL URLWithString:[dataArray objectForKey:@"pic_user"]];
NSData *Dataimage = [NSData dataWithContentsOfURL:urlimage];
cell.uploder_image.image =[UIImage imageWithData:Dataimage];
cell.uploder_image.clipsToBounds = YES;
cell.uploder_image.layer.cornerRadius = cell.uploder_image.frame.size.height /2;
cell.uploder_image.layer.borderWidth = 2.0;
cell.uploder_image.layer.borderColor = [UIColor whiteColor].CGColor;
cell.uploder_name.text=[dataArray valueForKeyPath:@"nama_user"];
cell.like_counter.text=[NSString stringWithFormat:@"%@",[dataArray valueForKeyPath:@"likes"]];
cell.commenter_name.text=[dataArray valueForKeyPath:@"status_timeline"];
cell.comments.text=[dataArray valueForKeyPath:@"tgl_timeline"];
[cell setSelectionStyle:UITableViewCellSelectionStyleNone];
return cell;
}
最佳答案
主要问题是,您在主线程中将图像 url 转换为 NSData
,这就是延迟滚动发生的原因。您需要在后台队列中将图像 url 转换为 NSData
并在主队列中更新 UI。
通过这种方式,您可以在后台加载每张图片,一旦加载,相应的单元格就会在主线程上更新。
下面的代码可能对你有帮助
NSURL *urlimage = [NSURL URLWithString:[dataArray objectForKey:@"pic_user"]];
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^(void) {
NSData *Dataimage = [NSData dataWithContentsOfURL:urlimage];
dispatch_sync(dispatch_get_main_queue(), ^(void) {
cell.uploder_image.image =[UIImage imageWithData:Dataimage];
});
});
关于ios - 滚动时 TableView 滞后,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/42710594/