ios UITableView 单元格附件视图图像问题
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/15349983/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
UITableView cell accessoryView image issue
提问by mindbomb
I am trying to display a 'padlock' icon on specific rows of my UITableViewCells using this code:
我正在尝试使用以下代码在 UITableViewCells 的特定行上显示“挂锁”图标：
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"TopicCell"];
GPBTopic *topic = [self.topics.list objectAtIndex:indexPath.row];
cell.textLabel.text= topic.name;
if ((indexPath.row == 5) || (indexPath.row == 9))
{
cell.accessoryView = [[ UIImageView alloc ] initWithImage:[UIImage imageNamed:@"lock_icon.png"]];;
[cell.accessoryView setFrame:CGRectMake(0, 0, 24, 24)];
}
return cell;
}
I am getting a funny result - the padlock is initially shown on rows 5,9 but when I scroll down and up the list the icon gets redisplayed by random on other cells' accessoryView as well (there's only 1 section btw), and the scrolling becomes quite jerky and laggy... The more I scroll up/down the more instances of it are displayed! Why? where's the bug here?
我得到了一个有趣的结果 - 挂锁最初显示在第 5,9 行，但是当我向下和向上滚动列表时，图标也会随机重新显示在其他单元格的附件视图上（顺便说一句，只有 1 个部分），并且滚动变得非常生涩和迟钝......我向上/向下滚动得越多，显示的实例就越多！为什么？这里的错误在哪里？
help, thanks!
帮助，谢谢！
回答by calimarkus
The cells get reused. You need to reset the accessoryView each time. Its just a small change:
细胞得到重用。您每次都需要重置附件视图。它只是一个小小的变化：
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"TopicCell"];
GPBTopic *topic = [self.topics.list objectAtIndex:indexPath.row];
cell.textLabel.text= topic.name;
if ((indexPath.row == 5) || (indexPath.row == 9))
{
cell.accessoryView = [[ UIImageView alloc ] initWithImage:[UIImage imageNamed:@"lock_icon.png"]];
[cell.accessoryView setFrame:CGRectMake(0, 0, 24, 24)];
} else {
cell.accessoryView = nil;
}
return cell;
}
Just for completion, you can also use Eric's solution like this - it may be faster, since the imageView is not created every time. But thats only a minimal difference. Probably your lags have other reasons.
只是为了完成，您也可以像这样使用 Eric 的解决方案 - 它可能更快，因为不是每次都创建 imageView。但这只是最小的区别。可能您的滞后有其他原因。
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = nil;
if(indexPath.row == 5 || indexPath.row == 9) {
cell = [tableView dequeueReusableCellWithIdentifier:@"TopicCellWithImage"];
cell.accessoryView = [[ UIImageView alloc ] initWithImage:[UIImage imageNamed:@"lock_icon.png"]];;
[cell.accessoryView setFrame:CGRectMake(0, 0, 24, 24)];
} else {
cell = [tableView dequeueReusableCellWithIdentifier:@"TopicCell"];
}
GPBTopic *topic = [self.topics.list objectAtIndex:indexPath.row];
cell.textLabel.text= topic.name;
return cell;
}
回答by Eric Qian
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell;
if(indexPath.row == 5 || indexPath.row == 9) {
cell = [tableView dequeueReusableCellWithIdentifier:@"TopicCellWithImage"];
} else {
cell = [tableView dequeueReusableCellWithIdentifier:@"TopicCell"];
}
GPBTopic *topic = [self.topics.list objectAtIndex:indexPath.row];
cell.textLabel.text= topic.name;
if ((indexPath.row == 5) || (indexPath.row == 9))
{
cell.accessoryView = [[ UIImageView alloc ] initWithImage:[UIImage imageNamed:@"lock_icon.png"]];;
[cell.accessoryView setFrame:CGRectMake(0, 0, 24, 24)];
}
return cell;
}
回答by Dary
To showing custom accessoryView cell in Swift 4 & Swift 5
在Swift 4 和 Swift 5 中显示自定义附件视图单元格
let lockIcon = UIImage(named: "lock_icon")
let lockIconView = UIImageView(image: lockIcon)
lockIconView.frame = CGRect(x: 0, y: 0, width: 24, height: 24)
cell.accessoryView = lockIconView
