UITableView 和单元格重用

Question

我有一个UITableView，并且我将UITableViewCell 子类化（称为CustomCell），所以它有多个标签和一个UIImageView。

只有某些单元格会实际显示图像。这是我的tableView:cellForRowAtIndexPath: 代码：

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {

    Match *aMatch = [[appDelegate.matchByDate objectAtIndex:indexPath.section] objectAtIndex:indexPath.row];
    static NSString *CellIdentifier = @"Cell";


    CustomCell *cell = (CustomCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[[CustomCell alloc] initWithFrame:CGRectZero reuseIdentifier:CellIdentifier] autorelease];
    }


    cell.homeLabel.text = aMatch.homeTeam;
    cell.awayLabel.text = aMatch.awayTeam;
    cell.timeLabel.text = aMatch.koTime;
    cell.tournamentLabel.text = aMatch.tournament;


    NSString *tempString = [appDelegate.teamLogos objectForKey:[aMatch homeTeam]];
    if (tempString!=nil) {
        cell.homeImageView.image = [UIImage imageNamed:tempString];
    }

    return cell;
}

所以它只在我设置的字典中找到相应的图像时设置homeImageView。这似乎适用于前几个单元格，但如果我滚动列表，我会发现单元格有图像，而它们不应该有图像。

我知道这可能是因为重复使用了单元格，但我在创建/重复使用单元格后设置了homeImageView？！

这是我的 CustomCell 类中的 init 方法

    - (id)initWithStyle:(UITableViewCellStyle)style
    reuseIdentifier:(NSString *)reuseIdentifier
{
    if (self = [super initWithStyle:style reuseIdentifier:reuseIdentifier]) {
        // Initialization code
        tournamentLabel = [[UILabel alloc] init];
        tournamentLabel.textAlignment = UITextAlignmentCenter;
        tournamentLabel.font = [UIFont systemFontOfSize:12];
        tournamentLabel.backgroundColor = [UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:0.0];  
        tournamentLabel.textColor = [UIColor darkGrayColor];
        homeLabel = [[UILabel alloc]init];
        homeLabel.textAlignment = UITextAlignmentLeft;
        homeLabel.font = [UIFont systemFontOfSize:16];
        homeLabel.backgroundColor = [UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:0.0];
        awayLabel = [[UILabel alloc]init];
        awayLabel.textAlignment = UITextAlignmentRight;
        awayLabel.font = [UIFont systemFontOfSize:16];
        awayLabel.backgroundColor = [UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:0.0];
        timeLabel = [[UILabel alloc]init];
        timeLabel.textAlignment = UITextAlignmentCenter;
        timeLabel.font = [UIFont systemFontOfSize:30];
        timeLabel.backgroundColor = [UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:0.0];
        timeLabel.textColor = [UIColor darkGrayColor];
        homeImageView = [[UIImageView alloc]init];
        awayImageView = [[UIImageView alloc]init];


        [self.contentView addSubview:homeLabel];
        [self.contentView addSubview:awayLabel];
        [self.contentView addSubview:timeLabel];
        [self.contentView addSubview:tournamentLabel];
        [self.contentView addSubview:homeImageView];
        [self.contentView addSubview:awayImageView];

    }
    return self;
}

Answer 1

如果没有要显示的图像，则必须清除图像视图：

...
if (tempString!=nil) {
    cell.homeImageView.image = [UIImage imageNamed:tempString];
} else {
    cell.homeImageView.image = nil;
}
...

Answer 2

您可以选择实现prepareForReuse:

在 Swift 中：

override func prepareForReuse() {
    cell.homeImageView.image = nil;
}