iphone - UITableView 滚动时重复单元格

Question

当我滚动我的 UITableView 时，出于某种原因，单元格似乎相互重叠。如果我加载我的应用程序，单元格将显示如下:

在屏幕上多次滚动此单元格并返回后，它将开始显示如下:

如您所见，我似乎无法解决的问题出了问题。有什么想法吗？

编辑:cellForRowAtIndexPath

static NSString *CellIdentifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
    }

    NSString *vaultsPath = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents/Vaults"];

    NSString *dictionaryPath = [NSString stringWithFormat:@"%@/%@",
                                vaultsPath,
                                [self.vaults objectAtIndex:indexPath.row]];
    NSDictionary *dictionary = [NSDictionary dictionaryWithContentsOfFile:dictionaryPath];
    cell = [AHCellCreation createCellWithDictionary:dictionary Cell:cell];

    return cell;

AHCellCreation +createCellWithDictionary:Cell:

//General cell design, same every time
CAGradientLayer *gradient = [CAGradientLayer layer];
gradient.frame = CGRectMake(0, 0, 320, 82);
gradient.colors = [NSArray arrayWithObjects:(id)[[UIColor colorWithHue:0 saturation:0 brightness:0.91 alpha:1] CGColor], (id)[[UIColor colorWithHue:0 saturation:0 brightness:0.85 alpha:1] CGColor], nil];
[cell.contentView.layer addSublayer:gradient];

UIView *topLine = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 1)];
topLine.backgroundColor = [UIColor colorWithHue:0 saturation:0 brightness:0.97 alpha:1.0];
[cell addSubview:topLine];

UIView *bottomLine = [[UIView alloc] initWithFrame:CGRectMake(0, 81, 320, 1)];
bottomLine.backgroundColor = [UIColor colorWithHue:0 saturation:0 brightness:0.64 alpha:1.0];
[cell addSubview:bottomLine];

//Preview Image
NSString *previewImageFilePath = [dictionary objectForKey:@"PreviewImage"];

UIImageView *previewImageView = [[UIImageView alloc] initWithFrame:CGRectMake(9, 9, 64, 64)];
previewImageView.image = [UIImage imageWithContentsOfFile:previewImageFilePath];
[cell addSubview:previewImageView];

//Creation date 
UILabel *createdOnLabel = [[UILabel alloc] init];
createdOnLabel.frame = CGRectMake(85, -5, 303, 41);
createdOnLabel.text = @"Created on";
createdOnLabel.backgroundColor = [UIColor clearColor];
createdOnLabel.textAlignment = UITextAlignmentLeft;
createdOnLabel.font = [UIFont systemFontOfSize:12];
createdOnLabel.textColor = [UIColor colorWithHue:0.59 saturation:0.29 brightness:0.47 alpha:1.0];
[cell addSubview:createdOnLabel];

NSDate *creationDate = [dictionary objectForKey:@"CreationDate"];
UILabel *creationDateLabel = [[UILabel alloc] initWithFrame:CGRectMake(85, 0, 303, 82)];
creationDateLabel.text = [AHCellCreation createReadableDateFromDate:creationDate];
creationDateLabel.backgroundColor = [UIColor clearColor];
creationDateLabel.textAlignment = UITextAlignmentLeft;
creationDateLabel.font = [UIFont boldSystemFontOfSize:28];
creationDateLabel.textColor = [UIColor colorWithHue:0.59 saturation:0.29 brightness:0.47 alpha:1.0];
[cell addSubview:creationDateLabel];

//Opening date
NSDate *notificationDate = [dictionary objectForKey:@"NotificationDate"];

NSDate *earliest = [notificationDate earlierDate:[NSDate date]];
BOOL notificationPassed;
if (earliest == [NSDate date]) {
    notificationPassed = YES;
}
else {
    notificationPassed = NO;
}

UILabel *notificationDateLabel = [[UILabel alloc] initWithFrame:CGRectMake(85, 47, 303, 41)];
if (notificationPassed == NO) {
    notificationDateLabel.text = @"To be opened";
}
else {
    notificationDateLabel.text = @"Opened on";
}
notificationDateLabel.backgroundColor = [UIColor clearColor];
notificationDateLabel.textAlignment = UITextAlignmentLeft;
notificationDateLabel.font = [UIFont systemFontOfSize:12];
notificationDateLabel.textColor = [UIColor colorWithHue:0.59 saturation:0.29 brightness:0.47 alpha:1.0];
[cell addSubview:notificationDateLabel];

UILabel *notificationDateLabel2 = [[UILabel alloc] init];
notificationDateLabel2.frame = CGRectMake(164, 47, 303, 41);
notificationDateLabel2.text = [AHCellCreation createReadableDateFromDate:notificationDate];
notificationDateLabel2.backgroundColor = [UIColor clearColor];
notificationDateLabel2.textAlignment = UITextAlignmentLeft;
notificationDateLabel2.font = [UIFont boldSystemFontOfSize:12];
notificationDateLabel2.textColor = [UIColor colorWithHue:0.59 saturation:0.29 brightness:0.47 alpha:1.0];
[cell addSubview:notificationDateLabel2];


return cell;

Answer 1

您只是在每次显示时向您的单元格添加越来越多的 UILabels 等!

您需要跟踪要添加到单元格中的所有内容，以确保只添加一次!有几种方法可以做到这一点，但我建议您自己对 UITableViewCell 进行子类化

例如，下面是让 createdOnLabel 正常工作的代码:

@interface AHTableViewCell : UITAbleViewCell {
    UILabel *createdOnLabel;
}

@end

@implementation AHTableViewCell

@end

然后，您的 cellForRowAtIndexPath 代码变为

AHTableViewCell *cell = (AHTableViewCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[AHTableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
    }

并且您的创建代码变为:

//Creation date
UILabel *createdOnLabel = [cell createdOnLabel];
if (nil == createdOnLabel) {
    createdOnLabel = [[UILabel alloc] init];
    createdOnLabel.frame = CGRectMake(85, -5, 303, 41);
    createdOnLabel.backgroundColor = [UIColor clearColor];
    createdOnLabel.textAlignment = UITextAlignmentLeft;
    createdOnLabel.font = [UIFont systemFontOfSize:12];
    createdOnLabel.textColor = [UIColor colorWithHue:0.59 saturation:0.29 brightness:0.47 alpha:1.0];
    [cell addSubview:createdOnLabel];
    [cell setCreatedOnLabel:createdOnLabel];
}
createdOnLabel.text = @"Created on";

因此，在您第一次创建单元格时，您就创建了标签。在您要求创建单元格的所有其他时间，您检查标签是否已经存在，如果存在，只需更新它的文本。