Question

我有一个自定义单元格。在cellForRowAtIndexPath方法中，我将indexPath.row号码显示为UILabel中定义的自定义cellForRowAtIndexPath。该标签将添加为该自定义单元格的子视图。当我有很多单元格并向下滑动tableview时，indexPath.row数字具有奇怪的值，如果我滚动更多，则值更高。我怎么能绕过这个？

[编辑]我的代码：

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"SKSTableViewCell";

    self.sksTableViewCell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    if (!self.sksTableViewCell)
        self.sksTableViewCell = [[SKSTableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];

    self.sksTableViewCell.textLabel.text = [NSString stringWithFormat:@"  %@",[[[ArraySingleton sharedManager].sharedArray objectAtIndex:indexPath.row] name]];
    self.sksTableViewCell.backgroundColor = [UIColor clearColor];

    if ([[[[ArraySingleton sharedManager].sharedArray objectAtIndex:indexPath.row] times] count]) {
        self.sksTableViewCell.expandable = YES;
    } else {
        self.sksTableViewCell.expandable = NO;
    }

    // UIButton for directly switching racers
    UIButton *stopwatchIcon = [UIButton buttonWithType:UIButtonTypeCustom];
    [stopwatchIcon addTarget:self action:@selector(pressedButtonToGoToTheRacerDirectly:) forControlEvents:UIControlEventTouchUpInside];
    UIImage *img = [UIImage imageNamed:@"stopwatch"];
    stopwatchIcon.frame = CGRectMake(self.view.bounds.size.width-70, 27.5-img.size.height/2, img.size.width, img.size.height);
    [stopwatchIcon setImage:img forState:UIControlStateNormal];
    stopwatchIcon.tag = [[self.indexDictionary valueForKey:[NSString stringWithFormat:@"%@", [[[ArraySingleton sharedManager].sharedArray objectAtIndex:indexPath.row] name]]] intValue];
    [self.sksTableViewCell addSubview:stopwatchIcon];

    // Medals
    int golds = [[self.bestThreeRacersDictionary objectForKey:@"golds"] intValue];
    int silvers = [[self.bestThreeRacersDictionary objectForKey:@"silvers"] intValue];
    int bronzes = [[self.bestThreeRacersDictionary objectForKey:@"bronzes"] intValue];

    // Medal image and view
    UIImage *medalImage = [UIImage imageNamed:@"medal"];
    UIImageView *medalImageView = [[UIImageView alloc] initWithFrame:CGRectMake(stopwatchIcon.frame.origin.x-medalImage.size.width-7.5, 27.5-medalImage.size.height/2, medalImage.size.width, medalImage.size.height)];
    // TextLabel
    UILabel *numberLabel = [[UILabel alloc] initWithFrame:CGRectMake(medalImageView.frame.origin.x+medalImageView.frame.size.width/4, medalImageView.frame.origin.y+medalImageView.frame.size.height/4, medalImageView.frame.size.width/2, medalImageView.frame.size.height/2)];
    numberLabel.backgroundColor = [UIColor clearColor];
    numberLabel.textColor = [UIColor whiteColor];
    numberLabel.textAlignment = NSTextAlignmentCenter;
    numberLabel.adjustsFontSizeToFitWidth = YES;
    numberLabel.font = [UIFont systemFontOfSize:12];
    numberLabel.text = [NSString stringWithFormat:@"%i", [Racer shift:golds silvers:silvers bronzes:bronzes]+helpIndex];
    helpIndex++;
    if (indexPath.row < golds) {
        medalImage = [UIImage imageNamed:@"goldMedal"];
        numberLabel.text = @"1";
        helpIndex--;
    } else if (indexPath.row < (golds+silvers)) {
        medalImage = [UIImage imageNamed:@"silverMedal"];
        numberLabel.text = @"2";
        helpIndex--;
    } else if (indexPath.row < (golds+silvers+bronzes)) {
        medalImage = [UIImage imageNamed:@"bronzeMedal"];
        numberLabel.text = @"3";
        helpIndex--;
    }
    medalImageView.image = medalImage;
    medalImageView.tag = 5;
    numberLabel.tag = 5;
    [self.sksTableViewCell addSubview:medalImageView];
    [self.sksTableViewCell addSubview:numberLabel];

    return self.sksTableViewCell;
}

Answer 1

避免在cellForRow方法中创建新的UIButtons和UILabel。 UITableView中的单元格被重用，因此滚动时从屏幕上消失的对象将再次用于显示新行。而且每次发生这种情况时你都会添加一个新的视图。

相反，您应该只创建一次所有视图层次结构并更新您需要更新的视图。

if (!cell) {
    cell = [[SKSTableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
    //create all your subviews here
}

//update subviews here

Answer 2

不要为每个单元格创建UI组件的新对象，然后在单元格重用之后执行一次。

indexPath.row给出了奇怪的值

2 个答案: