自定义UITableViewCell

Question

摘要

在自定义UITableViewCell中更改动画UIImage时。重新加载时（通常在滚动后），动画图像无法正确显示。

背景

我尝试使用表格视图实现音频播放列表。我需要在自定义单元格中显示一个图标，指示单元格的音频是否正在播放。

1）这是视图层次结构：

------------------------------------
| custom UITableViewCell           |
|      ------------------------    |
|      |   UIImageView        |    |
|      |   ---------------    |    |
|      |   |  UIImage    |    |    |
|      |   ---------------    |    |
|      ------------------------    |
------------------------------------

2）我有2张图片：

self.playIcon = [UIImage imageNamed:@"play"];
self.playingIcon = [UIImage animatedImageNamed:@"sentencePlayingNow" duration:0.5f];

3）当播放一个音频时，我在自定义UITableViewCell中设置了isPlaying属性。

// self.icon is a UIImageView
- (void)setPlaying:(BOOL)isPlaying
{
    if (isPlaying) {
        [self.icon setImage:self.playingIcon];
    } else {
        [self.icon setImage:self.playIcon];
    }
    _isPlaying = isPlaying;
}

4）我像这样重新加载tableView

// oldPlayingIndexPath and newPlayingIndexPath indicates current playing row.
if (oldPlayingIndexPath || newPlayingIndexPath) {
    dispatch_async(dispatch_get_main_queue(), ^{
        if (oldPlayingIndexPath) {
            [self.tableView reloadRowsAtIndexPaths:@[oldPlayingIndexPath] withRowAnimation:UITableViewRowAnimationNone];
        }
        if (newPlayingIndexPath) {
            [self.tableView reloadRowsAtIndexPaths:@[newPlayingIndexPath] withRowAnimation:UITableViewRowAnimationNone];
        }
    });
}

我的问题

当我设置isPlaying属性时。如果self.playingIcon是静态UIImage，一切都很好。如果self.playingIcon像我上面描述的那样动画，那么它是self.icon是不显示还是显示self.playIcon（静态的）？那是为什么？

原始截图：

滚动后进入：

更新

回复@RoryMcKinnel：我的cellForRowAtIndexPath代码

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    static NSString *CellIdentifier = @"SentenceTableViewCell";
    SentenceTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];

    [self configureCell:cell forRowAtIndexPath:indexPath];

    return cell;
}


- (void)configureCell:(SentenceTableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
{
    Sentence *sentence = [self.fetchedResultsController objectAtIndexPath:indexPath];
    [cell setTitle:sentence.text];

    if ([self.article.allowsEditing boolValue] || (sentence.audio_url.length > 0)) {
        [cell setCanPlay:YES];
    } else {
        [cell setCanPlay:NO];
    }

    cell.playIcon = self.playIcon;
    cell.playingIcon = self.playingIcon;
    cell.OKIcon = self.OKIcon;
    cell.isPlaying = self.currentPlayingIndexPath && [self.currentPlayingIndexPath compare:indexPath] == NSOrderedSame;

    __weak EditViewController *weakSelf = self;
    cell.play = ^void() {
        [weakSelf playSentenceAtIndexPath:indexPath];
    };
    cell.stop = ^void() {
        [weakSelf.player pause];
        weakSelf.currentPlayingIndexPath = nil;
    };
    cell.edit = ^void() {
        weakSelf.tableView.editing = YES;
    };
}

Answer 1

这很可能是由于可重用性。您需要确保在重用或重新创建单元格时重新加载正确的图像。一个提示，您可能不希望错误的图标在出现正确的图标之前短暂闪烁，因此我会在didEndDisplayingCell中将imageView设置为nil，并始终在viewForRowAtIndexPath

中重新创建图标