查看Table View Programming Guide中的自定义单元格。但是,故事板、NIB 或以编程方式创建的单元格之间的细节有所不同。您必须分享您的和您的,以便我们诊断正在发生的事情。下面,我将向您展示一个使用旋转活动指示器的示例,但这里没有什么特别之处。我怀疑您的应用程序发生了一些简单的事情,但除非我们能看到您的代码,否则我们无法为您提供帮助。UITableViewCell
tableView:cellForRowAtIndexPath:
tableView:didSelectRowAtIndexPath:
但是,为了向您展示一个示例,假设您已UITableViewCell
使用 Interface Builder 中定义的接口进行子类化。didSelectRowAtIndexPath
这是一个启动旋转活动指示器并在 15 秒后将其关闭的示例。
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
TestCell *cell = (TestCell *)[tableView cellForRowAtIndexPath:indexPath];
// I have a model in my app for the sections of the tableview, as well as the rows,
// so let's get the pointer to the appropriate model information. Your implementation
// may differ, but hopefully you get the idea.
Section *section = self.sections[indexPath.section];
Row *row = section.rows[indexPath.row];
// because we selected this row, start the activity indicator
[cell addActivityIndicator];
// let's flag the row in our model to indicate that we're busy here (so if and when
// we represent this row, we'll know if we're busy or not)
row.loading = YES;
// and let's asynchronously dispatch a "stop activity indicator" in 15 seconds
int64_t delayInSeconds = 15.0;
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds * NSEC_PER_SEC);
dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
// because this is happening asynchronously, let's re-retrieve the cell
// pointer, just in case it might have scrolled off of the visible screen
// as is no longer visible or the pointer to the cell might have changed
TestCell *currentCell = (TestCell *)[tableView cellForRowAtIndexPath:indexPath];
// let's remove the activity indicator
[currentCell removeActivityIndicator];
// let's flag our model to indicate that this row is no longer loading
row.loading = NO;
});
}
在这种情况下,我需要确保tableView:cellForRowAtIndexPath:
查看模型数据以确定它是否也需要显示旋转活动指示器:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"TestCell";
TestCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
// if I'm using storyboards, the following isn't needed, but if not, I might use something
// like the following to load the custom cell from a NIB
//if (cell == nil)
//{
// NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"TestCell" owner:self options:nil];
// cell = (TestCell *)[nib objectAtIndex:0];
//}
// this happens to be my model structure, where I have an array of sections,
// and each section has its array of Row objects for that section
Section *section = self.sections[indexPath.section];
Row *row = section.rows[indexPath.row];
// each "Row" object has two text fields, which I use to update the
// two labels in my TestCell subclass of UITableViewCell
cell.label1.text = row.text1;
cell.label2.text = row.text2;
// for this row of this section, figure out whether I need to start animating
// the UIActivityIndicator
if (row.loading)
[cell addActivityIndicator];
else
[cell removeActivityIndicator];
return cell;
}
在我的子类UITableViewCell
中是添加和删除活动指示器的代码:
@interface TestCell ()
@property (strong, nonatomic) UIActivityIndicatorView *activity;
@end
@implementation TestCell
- (void)addActivityIndicator
{
if (!self.activity)
{
self.activity = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
self.activity.center = self.contentView.center;
}
[self.contentView addSubview:self.activity];
[self.activity startAnimating];
}
- (void)removeActivityIndicator
{
if (self.activity)
{
[self.activity stopAnimating];
[self.activity removeFromSuperview];
self.activity = nil;
}
}
@end
这只是它如何工作的一个简单示例,但实现可能会有很大差异(取决于 NIB、故事板、以编程方式创建控件、应用程序模型的性质等)。与其尝试为您的应用修改上述代码,不如与我们共享您的代码可能会更容易,我们希望能够很快发现问题。问题可能很简单。