我在iOS中创建了一个自定义单元格。在自定义单元格中有许多标签。对于少数标签，第一个和第一个数据的数据。第四个自定义单元格总是一样的。我的数据源数组总共有5条记录。现在我遇到这些问题。
请告诉我如何解决此问题。
CODE：
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSLog(@"cell for row called %d",(int)[arr_post count]);
//define variables here
NSMutableAttributedString *mutableAttributeStr;
NSAttributedString *attributeStr;
static NSString *CellIdentifier = @"homeCell";
float x_pos;
HomeCell *cell = [self.table_view
dequeueReusableCellWithIdentifier:CellIdentifier
forIndexPath:indexPath];
[cell setSelectionStyle:UITableViewCellSelectionStyleNone];
//get the post data
Post *user_post=[arr_post objectAtIndex:indexPath.row];
cell.tv_post.text=user_post.post_description;
cell.tv_post.font = [UIFont fontWithName:user_post.font_family size:[user_post.font_size floatValue]];
cell.label_name.text=user_post.post_title;
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
NSDate *date = [formatter dateFromString:user_post.modification_date];
if([user_post.post_image isEqualToString:@"none"] && [user_post.post_video isEqualToString:@"none"])
{
x_pos=cell.tv_post.frame.origin.x;
cell.tv_post_leading_space.constant=-(x_pos);
[cell.img_post setHidden:true];
}
//set the like count
NSString *first_like_user=user_post.recent_like_name;
int count=(int)[first_like_user length];
float like_count=[user_post.like_count intValue];
//chek if tehre are any likes on the post
NSLog(@"recent like name is %@",user_post.recent_like_name);
NSLog(@"like count is %f",like_count);
if(like_count>0)
{
NSLog(@"inside like count block");
NSString *str_like_count=[NSString stringWithFormat:@"%lu",(unsigned long)like_count-1];
if(like_count==1)
{
if([myUsername isEqualToString:first_like_user])
{
first_like_user=@"You like this post";
count=3;
}
else
{
first_like_user=[first_like_user stringByAppendingString:@" like this post"];
}
}
else if(like_count==2)
{
first_like_user=[first_like_user stringByAppendingString:@" and "];
str_like_count=[str_like_count stringByAppendingString:@" other like this post"];
first_like_user=[first_like_user stringByAppendingString:str_like_count];
}
else
{
if(like_count>1000)
{
like_count=like_count/1000;
str_like_count=[NSString stringWithFormat:@"%lu",(unsigned long)like_count];
str_like_count=[str_like_count stringByAppendingString:@"k"];
first_like_user=[first_like_user stringByAppendingString:@" and "];
str_like_count=[str_like_count stringByAppendingString:@" others like this post"];
first_like_user=[first_like_user stringByAppendingString:str_like_count];
}
else
{
first_like_user=[first_like_user stringByAppendingString:@" and "];
str_like_count=[str_like_count stringByAppendingString:@" others like this post"];
first_like_user=[first_like_user stringByAppendingString:str_like_count];
}
}
mutableAttributeStr = [[NSMutableAttributedString alloc]initWithString:first_like_user];
attributeStr = [[NSAttributedString alloc]initWithString:@"\n" attributes:@{NSFontAttributeName : [UIFont fontWithName:@"HelveticaNeue-Bold" size:8]}];
[mutableAttributeStr addAttribute:NSFontAttributeName value: [UIFont fontWithName:@"Helvetica-Bold" size:14.0] range:NSMakeRange(0, count)];
[mutableAttributeStr addAttribute:NSForegroundColorAttributeName value:[self colorFromHexString:@"#48a0dd"] range:NSMakeRange(0, count)];
[mutableAttributeStr appendAttributedString:attributeStr];
//set the like label dynamic height & width
cell.label_like_count.attributedText = mutableAttributeStr;
CGSize maximumLabelSize = CGSizeMake(187,9999);
CGSize requiredSize = [cell.label_like_count sizeThatFits:maximumLabelSize];
CGRect labelFrame = cell.label_like_count.frame;
labelFrame.size.height = requiredSize.height;
cell.label_like_count.frame = labelFrame;
// cell.label_like_count.lineBreakMode = NSLineBreakByWordWrapping;
cell.label_like_count.numberOfLines = 0;
[cell.label_like_count sizeToFit];
[cell.label_like_count setAttributedText:mutableAttributeStr];
}
//show dynamic comment
NSMutableArray *user_comments=user_post.comments;
float comment_count=[user_post.comment_count intValue];
NSLog(@"arr comments count is %lu",(unsigned long)comment_count);
if(comment_count>0)
{
NSLog(@"post id is %@",user_post.id);
NSMutableAttributedString *mutableAttributeStr;
NSAttributedString *attributeStr;
for(l=0;l<[user_comments count];l++)
{
NSLog(@"inside loop %d",l);
Comment *comment=[user_comments objectAtIndex:l];
if(l==0)
{
NSLog(@"l is zero");
NSString *comment_string=[comment.user_name stringByAppendingString:@" "];
comment_string=[comment_string stringByAppendingString:comment.comment];
int count=(int)[comment.user_name length];
mutableAttributeStr = [[NSMutableAttributedString alloc]initWithString:comment_string];
NSLog(@"comment string is %@",comment_string);
attributeStr = [[NSAttributedString alloc]initWithString:@"\n" attributes:@{NSFontAttributeName : [UIFont fontWithName:@"HelveticaNeue-Bold" size:8]}];
[mutableAttributeStr addAttribute:NSFontAttributeName value: [UIFont fontWithName:@"Helvetica-Bold" size:14.0] range:NSMakeRange(0, count)];
[mutableAttributeStr addAttribute:NSForegroundColorAttributeName value:[self colorFromHexString:@"#48a0dd"] range:NSMakeRange(0, count)];
[mutableAttributeStr appendAttributedString:attributeStr];
[cell.first_comment setAttributedText:mutableAttributeStr];
}
else if(l==1)
{
NSLog(@"l is 1");
NSString *comment_string=[comment.user_name stringByAppendingString:@" "];
comment_string=[comment_string stringByAppendingString:comment.comment];
int count=(int)[comment.user_name length];
mutableAttributeStr = [[NSMutableAttributedString alloc]initWithString:comment_string];
attributeStr = [[NSAttributedString alloc]initWithString:@"\n" attributes:@{NSFontAttributeName : [UIFont fontWithName:@"HelveticaNeue-Bold" size:8]}];
[mutableAttributeStr addAttribute:NSFontAttributeName value: [UIFont fontWithName:@"Helvetica-Bold" size:14.0] range:NSMakeRange(0, count)];
[mutableAttributeStr addAttribute:NSForegroundColorAttributeName value:[self colorFromHexString:@"#48a0dd"] range:NSMakeRange(0, count)];
NSLog(@"comment string is %@",comment_string);
[mutableAttributeStr appendAttributedString:attributeStr];
[cell.second_cmment setAttributedText:mutableAttributeStr];
}
else if(l==2)
{
NSLog(@"l is 2");
NSString *comment_string=[comment.user_name stringByAppendingString:@" "];
comment_string=[comment_string stringByAppendingString:comment.comment];
int count=(int)[comment.user_name length];
mutableAttributeStr = [[NSMutableAttributedString alloc]initWithString:comment_string];
attributeStr = [[NSAttributedString alloc]initWithString:@"\n" attributes:@{NSFontAttributeName : [UIFont fontWithName:@"HelveticaNeue-Bold" size:8]}];
[mutableAttributeStr addAttribute:NSFontAttributeName value: [UIFont fontWithName:@"Helvetica-Bold" size:14.0] range:NSMakeRange(0, count)];
[mutableAttributeStr addAttribute:NSForegroundColorAttributeName value:[self colorFromHexString:@"#48a0dd"] range:NSMakeRange(0, count)];
[mutableAttributeStr appendAttributedString:attributeStr];
[cell.third_comment setAttributedText:mutableAttributeStr];
}
}
}
else
{
NSLog(@"not inside loop");
}
cell.label_time.text=[BaseController getTimestampForDate:date];
return cell;
}
修改 我已经阅读了某些地方，出于性能原因，UITable恢复了单元格。因为我觉得当有超过3行时我会遇到这个问题。
修改
如果我尝试不使用if(like_count>0)＆amp;条件，我在这里发现了一个奇怪的情况。只需在不符合条件的情况下设置文本标签，然后它就可以正常使用。
提前致谢。
答案 0 :(得分：5)
单元格被重用，因此您必须覆盖执行路径中的所有情况。
正如您已经发现的那样，if(like_count>0)和if(comment_count>0)意味着如果没有计数，则文本标签不会更改，旧值将保留在那里。
您必须添加} else { cell.label_like_count.attributedText = nil }种代码才能涵盖所有情况。或者，您可以在单元类中的- (void)prepareForReuse中添加一些清理代码（不要忘记[super prepareForReuse]）。
答案 1 :(得分：1)
在HomeCell覆盖prepareForReuse:。在该方法中，在所有标签上将.text（或.attributedText）属性设置为nil。然后看看会发生什么。
答案 2 :(得分：1)
重复使用单元格，表格始终只创建当前可见的单元格。显示屏幕时，将显示三个单元格。当您滚动并且一个单元格被隐藏而另一个单元格出现时，它实际上是相同的单元格实例。
处理此行为的常用方法是子类UITableViewCell并在那里进行所有设置。可以将重置为默认状态添加到-prepareForReuse方法，例如
- (void)prepareForReuse {
[super prepareForReuse];
self.first_comment.text = nil;
self.second_comment.text = nil;
self.third_comment.text = nil;
}
要修复代码而不使用特定的单元子类，让我们首先通过从代码中删除重复模式来简化：
for (NSUInteger i = 0; i < [user_comments count]; i++) { //i is the traditional variable name for iterating
Comment *comment = user_comments[i]; //updating to newer syntax
// start of the repetitive pattern
NSString *comment_string=[comment.user_name stringByAppendingString:@" "];
comment_string=[comment_string stringByAppendingString:comment.comment];
int count=(int)[comment.user_name length];
NSMutableAttributedString* mutableAttributeStr = [[NSMutableAttributedString alloc]initWithString:comment_string];
NSAttributedString attributeStr = [[NSAttributedString alloc]initWithString:@"\n" attributes:@{NSFontAttributeName : [UIFont fontWithName:@"HelveticaNeue-Bold" size:8]}];
[mutableAttributeStr addAttribute:NSFontAttributeName value: [UIFont fontWithName:@"Helvetica-Bold" size:14.0] range:NSMakeRange(0, count)];
[mutableAttributeStr addAttribute:NSForegroundColorAttributeName value:[self colorFromHexString:@"#48a0dd"] range:NSMakeRange(0, count)];
[mutableAttributeStr appendAttributedString:attributeStr];
// end of the repetitive pattern
if (i == 0) {
[cell.first_comment setAttributedText:mutableAttributeStr];
}
else if (i == 1) {
[cell.second_comment setAttributedText:mutableAttributeStr];
}
else if (i == 2) {
[cell.third_comment setAttributedText:mutableAttributeStr];
}
}
现在您可以将其与重置值结合使用：
NSArray *commentLabels = @[cell.first_comment, cell.second_comment, cell.third_comment];
for (NSUInteger i = 0; i < 3; i++) {
UILabel *label = commentLabels[i];
// reset if there is no comment
if (i >= [user_comments count]) {
label.text = nil;
continue;
}
Comment *comment = user_comments[i];
NSString *comment_string = [NSString stringWithFormat:@"%@ %@", comment.user_name, comment.comment];
int count = (int)[comment.user_name length];
NSMutableAttributedString* mutableAttributeStr = [[NSMutableAttributedString alloc]initWithString:comment_string];
NSAttributedString attributeStr = [[NSAttributedString alloc]initWithString:@"\n" attributes:@{NSFontAttributeName : [UIFont fontWithName:@"HelveticaNeue-Bold" size:8]}];
[mutableAttributeStr addAttribute:NSFontAttributeName value:[UIFont fontWithName:@"Helvetica-Bold" size:14.0 range:NSMakeRange(0, count)];
[mutableAttributeStr addAttribute:NSForegroundColorAttributeName value:[self colorFromHexString:@"#48a0dd"] range:NSMakeRange(0, count)];
[mutableAttributeStr appendAttributedString:attributeStr];
label.attributedText = mutableAttributeStr;
}
答案 3 :(得分：0)
检查表格中的元素数量，并确保代理 numberOfRowsInSection 中的数字正确无误：
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
return the_correct_items_number;
}
如果计数正确，请尝试使用本地数组（仅用于测试）。注意：如果使用网络请求更新源阵列，请考虑使用dispatch_async调用来更新内容。
答案 4 :(得分：0)
在自定义单元格中使用方法prepareForReuse。
//如果单元格是可重用的（具有重用标识符），则在从表视图方法dequeueReusableCellWithIdentifier：返回单元格之前调用它。如果你覆盖，你必须调用super。
- (void) prepareForReuse {
// set empty or nil of your repeated element .
[super prepareForReuse];
}
希望对你有所帮助。
答案 5 :(得分：-1)
尝试替换
if (cell==nil)
{
cell = [[HomeCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
与
//if (cell==nil)
//{
cell = [[HomeCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
// }
答案 6 :(得分：-1)
将单元格出列后，请写下以下行： -
[cell.subviews makeObjectsPerformSelector:@selector(removeFromSuperview)];