多个自定义单元格的 UITableView 滚动不流畅

【问题标题】：UITableView scrolling is not smooth with multiple custom cells多个自定义单元格的 UITableView 滚动不流畅
【发布时间】：2016-11-03 10:55:15
【问题描述】：

以下是索引路径中行单元格的完整代码——这里的表格视图是多个自定义单元格，应该根据值返回。滚动表格视图滞后很多..我正在使用 YYWebimage 进行图像加载，并且单元格的内容不断变化，需要显示表格视图行高的高度，

- (UITableViewCell *)tableView:(UITableView*)tableView cellForRowAtIndexPath:(NSIndexPath*)indexPath
{
    KVembedLinkTableViewCell* KVCell = [tableView dequeueReusableCellWithIdentifier:@"Link"];

    [KVCell flushCell];
    [KVCell layoutIfNeeded];
    _postDict = [NSMutableDictionary dictionaryWithDictionary:[cardDetailsArray objectAtIndex:indexPath.row]];
    NSLog(@"feedstimeline postdict: %@",_postDict);
    [_postDict setObject:indexPath forKey:KEY_INDEXPATH];
    NSArray *embedlist = [NSArray new];
    embedlist = [_postDict valueForKeyPath:@"recentpost.embedlist"];
    NSArray *medialist = [NSArray new];
    medialist = [_postDict valueForKeyPath:@"recentpost.medialist"];
    KVCell.embededDetails = _postDict;
    KVCell.embedlist = embedlist;

    NSString *discription = [NSString stringWithFormat:@"%@",[_postDict valueForKeyPath:@"recentpost.staticdata.contenttext"]];
    discription = [CVUtilityManager stripEmptyTags:discription];
    KVCell.userDescription.preferredMaxLayoutWidth = _timeLineTableView.bounds.size.width -16;
    [KVCell.userDescription setText:discription];
    NSAttributedString *attr = [CVUtilityManager UserDescription:discription];
    KVCell.userDescriptionHeight.constant =[CVUtilityManager sizeForLabel:KVCell.userDescription withAttributedString:attr];
    [KVCell laodUserDescription:attr];
    [KVCell.userDescription updateConstraints];
    [KVCell.userDescription setNeedsLayout];
    [KVCell.userDescription layoutIfNeeded];
    [KVCell setLikeDelegate:self];
    NSString *typeOfCardString = cardTypeArray[indexPath.row];
    if ([CVUtilityManager stringIsNull:typeOfCardString]) typeOfCardString =  @"UNKNOWN";
    _typeOfCard = [self defineCardTypeFromType:typeOfCardString];
    switch (_typeOfCard) {

        case VIDEO: {

            if (embedlist.count > 0 ) {
                if (embedlist[0] != nil) {
                    [KVCell loadVideoDetails:[NSMutableDictionary dictionaryWithDictionary:embedlist[0]]];
                }else
                    KVCell.linkViewHeight.constant = 0;
            }else
                KVCell.linkViewHeight.constant = 0;

            [KVCell performSelector:@selector(laodCellContents) onThread:[NSThread mainThread] withObject:nil waitUntilDone:TRUE];

        } break;
        case UNKNOWN:
        case TEXT: {
            [KVCell loadTextWithString];
            KVCell.linkViewHeight.constant = 0;
            KVCell.multiTableViewHeight.constant = 0;
            [KVCell laodCellContents];
            [KVCell.linkContentView layoutIfNeeded];
            [KVCell.linkContentView updateConstraints];
            [KVCell layoutIfNeeded];
            [KVCell setNeedsLayout];
            [KVCell updateConstraints];
            NSLog(@"card type TEXT");
        }break;
        case EMBEDFB: {
            if (embedlist.count > 0 ) {
                if (embedlist[0] != nil) {
                    NSString *URLFB = [embedlist[0] objectOrNilForKey:@"url"];
                    [KVCell loadFaceBookDetails:[CVUtilityManager neutraliseString:URLFB] withVideoButtonStatus:NO];
                }else
                    KVCell.linkViewHeight.constant = 0;
            }else
                KVCell.linkViewHeight.constant = 0;

            [KVCell performSelector:@selector(laodCellContents) onThread:[NSThread mainThread] withObject:nil waitUntilDone:TRUE];

        } break;
        case EMBEDINSTAGRAM: {

            if (embedlist.count > 0 ) {
                if (embedlist[0] != nil) {
                    NSString *URLINSTA = [embedlist[0] objectOrNilForKey:@"url"];
                    [KVCell loadInstagramDetails:[CVUtilityManager neutraliseString:URLINSTA]];
                }else
                    KVCell.linkViewHeight.constant = 0;
            }else
                KVCell.linkViewHeight.constant = 0;

            [KVCell performSelector:@selector(laodCellContents) onThread:[NSThread mainThread] withObject:nil waitUntilDone:TRUE];

        } break;

        case EMBEDPHOTO: {

            if (embedlist.count > 0 ) {
                if (embedlist[0] != nil) {
                    KVCell.linkViewHeight.constant = 253;
                    [KVCell embedPhoto:[NSMutableDictionary dictionaryWithDictionary:embedlist[0]]];

                }else
                    KVCell.linkViewHeight.constant = 0;
            }else
                KVCell.linkViewHeight.constant = 0;
            KVCell.multiTableViewHeight.constant = 0;
            KVCell.userDescription.preferredMaxLayoutWidth = _timeLineTableView.bounds.size.width -16;
            [KVCell.userDescription setText:discription];
            NSAttributedString *attr = [CVUtilityManager UserDescription:discription];
            KVCell.userDescriptionHeight.constant =[CVUtilityManager sizeForLabel:KVCell.userDescription withAttributedString:attr];
            [KVCell laodUserDescription:attr];
            [KVCell.userDescription updateConstraints];
            [KVCell.userDescription setNeedsLayout];
            [KVCell.userDescription layoutIfNeeded];


            [KVCell performSelector:@selector(laodCellContents) onThread:[NSThread mainThread] withObject:nil waitUntilDone:TRUE];
        } break;
        case KANVZPOST:
        case LINK: {

            if (embedlist.count > 0 ) {
                if (embedlist[0] != nil) {
                    KVCell.linkViewHeight.constant = 253;
                    [KVCell loadLinkView:[NSMutableDictionary dictionaryWithDictionary:embedlist[0]]];

                }else
                    KVCell.linkViewHeight.constant = 0;
            }else
                KVCell.linkViewHeight.constant = 0;
            KVCell.multiTableViewHeight.constant = 0;

            [KVCell performSelector:@selector(laodCellContents) onThread:[NSThread mainThread] withObject:nil waitUntilDone:TRUE];

        } break;
        case SOUND_CLOUD_AUDIO:
        case MULTI_SOUND_CLOUD_AUDIO: {
            NSLog(@"card type MULTI_SOUND_CLOUD_AUDIO");
            if (embedlist.count > 0 ) {
                [KVCell loadAudioLinksWithArray:embedlist];
                KVCell.multiTableViewHeight.constant = embedlist.count * 132.00;
                KVCell.linkViewHeight.constant = 0;
            }else
                KVCell.multiTableViewHeight.constant = 0;
            KVCell.userDescription.preferredMaxLayoutWidth = _timeLineTableView.bounds.size.width -16;
            [KVCell.userDescription setText:discription];
            NSAttributedString *attr = [CVUtilityManager UserDescription:discription];
            KVCell.userDescriptionHeight.constant =[CVUtilityManager sizeForLabel:KVCell.userDescription withAttributedString:attr];
            [KVCell laodUserDescription:attr];
            [KVCell.userDescription updateConstraints];
            [KVCell.userDescription setNeedsLayout];
            [KVCell.userDescription layoutIfNeeded];

            [KVCell performSelector:@selector(laodCellContents) onThread:[NSThread mainThread] withObject:nil waitUntilDone:TRUE];


        } break;
        case EMBEDRICH:
        case MULTIPLE_LINK: {
            if (embedlist.count > 0 ) {
                [KVCell loadMultiLinksWithArray:embedlist];
                KVCell.linkViewHeight.constant = 0;
            }else
                KVCell.linkViewHeight.constant = 0;

            [KVCell performSelector:@selector(laodCellContents) onThread:[NSThread mainThread] withObject:nil waitUntilDone:TRUE];


        } break;
        case FACEBOOK_VIDEO_CARD: {
            if (embedlist.count > 0 ) {
                if (embedlist[0] != nil) {
                    NSString *URLFB = [embedlist[0] objectOrNilForKey:@"url"];
                    [KVCell loadFaceBookDetails:[CVUtilityManager neutraliseString:URLFB] withVideoButtonStatus:YES];

                }else
                    KVCell.linkViewHeight.constant = 0;
            }else
                KVCell.linkViewHeight.constant = 0;

            [KVCell performSelector:@selector(laodCellContents) onThread:[NSThread mainThread] withObject:nil waitUntilDone:TRUE];

        } break;
        case AUDIO: {
            [_postDict setObject:indexPath forKey:KEY_INDEXPATH];
            KVembedAudio
            * KVCellAUDIO = [tableView dequeueReusableCellWithIdentifier:@"Audio" forIndexPath:indexPath];
            KVCellAUDIO.embededDetails = _postDict;
            [KVCellAUDIO setLikeDelegate:self];
            KVCellAUDIO.userDescription.preferredMaxLayoutWidth = _timeLineTableView.bounds.size.width -16;
            [KVCellAUDIO.userDescription setText:discription];
            NSAttributedString *attr = [CVUtilityManager UserDescription:discription];
            KVCellAUDIO.userDescrptionHeight.constant =[CVUtilityManager sizeForLabel:KVCell.userDescription withAttributedString:attr];
            [KVCellAUDIO laodUserDescription:attr];
            [KVCellAUDIO.userDescription updateConstraints];
            [KVCellAUDIO.userDescription setNeedsLayout];
            [KVCellAUDIO.userDescription layoutIfNeeded];

            [KVCellAUDIO performSelector:@selector(laodCellContents) onThread:[NSThread mainThread] withObject:nil waitUntilDone:true];
            [KVCellAUDIO.contentView layoutIfNeeded];
            NSLog(@"card type AUDIO");
            return KVCellAUDIO;
        } break;
        case PHOTO: {
            KVCell.embedlist = medialist;
            if (medialist.count > 0 ) {
                if (medialist[0] != nil) {

                    [KVCell uploadPhoto:[NSMutableDictionary dictionaryWithDictionary:medialist[0]]];

                }else
                    KVCell.linkViewHeight.constant = 0;
            }else
                KVCell.linkViewHeight.constant = 0;
            KVCell.userDescription.preferredMaxLayoutWidth = _timeLineTableView.bounds.size.width -16;
            [KVCell.userDescription setText:discription];
            NSAttributedString *attr = [CVUtilityManager UserDescription:discription];
            KVCell.userDescriptionHeight.constant =[CVUtilityManager sizeForLabel:KVCell.userDescription withAttributedString:attr];
            [KVCell laodUserDescription:attr];
            [KVCell.userDescription updateConstraints];
            [KVCell.userDescription setNeedsLayout];
            [KVCell.userDescription layoutIfNeeded];
            [KVCell performSelector:@selector(laodCellContents) onThread:[NSThread mainThread] withObject:nil waitUntilDone:TRUE];
        } break;

        case MULTIPLE_EMBEDPHOTO: {
            NSLog(@"card type MULTIPLE_EMBEDPHOTO");
            [_postDict setObject:indexPath forKey:KEY_INDEXPATH];
            NSArray *mediaList =  [[_postDict objectOrNilForKey:@"recentpost"] objectOrNilForKey:@"embedlist"];
            KVembedPhotoMultiple
            * KVCellPhoto = [tableView dequeueReusableCellWithIdentifier:@"Photo Multiple" forIndexPath:indexPath];
            [KVCellPhoto flushCell];
            KVCellPhoto.embededDetails = _postDict;
            if (mediaList.count>0) {
                [KVCellPhoto loadEmbedPhotos:mediaList];
            }
            [KVCellPhoto setLikeDelegate:self];
            KVCellPhoto.userDescription.preferredMaxLayoutWidth = _timeLineTableView.bounds.size.width -16;
            [KVCellPhoto.userDescription setText:discription];
            NSAttributedString *attr = [CVUtilityManager UserDescription:discription];
            KVCellPhoto.userDescrptionHeight.constant =[CVUtilityManager sizeForLabel:KVCell.userDescription withAttributedString:attr];
            [KVCellPhoto laodUserDescription:attr];
            [KVCellPhoto.userDescription updateConstraints];
            [KVCellPhoto.userDescription setNeedsLayout];
            [KVCellPhoto.userDescription layoutIfNeeded];

            [KVCellPhoto performSelector:@selector(laodCellContents) onThread:[NSThread mainThread] withObject:nil waitUntilDone:TRUE];
            [KVCellPhoto.contentView layoutIfNeeded];
            return KVCellPhoto;
        } break;

        case MULTIPLE_PHOTO: {
            NSLog(@"card type MULTIPLE_PHOTO");
            [_postDict setObject:indexPath forKey:KEY_INDEXPATH];
            NSArray *mediaList =  [[_postDict objectOrNilForKey:@"recentpost"] objectOrNilForKey:@"medialist"];
            NSLog(@"mediaList  %@",mediaList);
            KVembedPhotoMultiple
            * KVCellPhoto = ( KVembedPhotoMultiple *)[tableView dequeueReusableCellWithIdentifier:@"Photo Multiple" forIndexPath:indexPath];
            [KVCellPhoto flushCell];
            KVCellPhoto.embededDetails = _postDict;
            if (mediaList.count>0) {
                [KVCellPhoto loadUploadedPhotos:mediaList];
            }
            [KVCellPhoto setLikeDelegate:self];
            KVCellPhoto.userDescription.preferredMaxLayoutWidth = _timeLineTableView.bounds.size.width -16;
            [KVCellPhoto.userDescription setText:discription];
            NSAttributedString *attr = [CVUtilityManager UserDescription:discription];
            KVCellPhoto.userDescrptionHeight.constant =[CVUtilityManager sizeForLabel:KVCell.userDescription withAttributedString:attr];
            [KVCellPhoto laodUserDescription:attr];
            [KVCellPhoto.userDescription updateConstraints];
            [KVCellPhoto.userDescription setNeedsLayout];
            [KVCellPhoto.userDescription layoutIfNeeded];

            [KVCellPhoto performSelector:@selector(laodCellContents) onThread:[NSThread mainThread] withObject:nil waitUntilDone:TRUE];
            [KVCellPhoto.contentView layoutIfNeeded];
            return KVCellPhoto;
        } break;
        case EMBED_MUL_VIDEO: {
            [_postDict setObject:indexPath forKey:KEY_INDEXPATH];
            KVembedVideoMultipleTableViewCell
            * KVCellVideo = [tableView dequeueReusableCellWithIdentifier:@"Video Multiple" forIndexPath:indexPath];
            KVCellVideo.embededDetails = _postDict;
            [KVCellVideo setLikeDelegate:self];
            [KVCellVideo performSelector:@selector(laodCellContents) onThread:[NSThread mainThread] withObject:nil waitUntilDone:TRUE];
            [KVCellVideo.contentView layoutIfNeeded];
            NSLog(@"card type EMBED_MUL_VIDEO");
            return KVCellVideo;
        } break;
        case EMBEDTWEET:
        case EMBED_MUL_TWEET: {
            NSLog(@"card type EMBED_MUL_TWEET");
            [_postDict setObject:indexPath forKey:KEY_INDEXPATH];
            KVembedTweetMultiple* KVCellTweet = [tableView dequeueReusableCellWithIdentifier:@"Tweet Multiple" forIndexPath:indexPath];
            [KVCellTweet setLikeDelegate:self];
            KVCellTweet.embededDetails = _postDict;
            KVCellTweet.embedlist = embedlist;
            [KVCellTweet.userDescription setText:discription];
            KVCellTweet.userDescriptionHeight.constant = [CVUtilityManager sizeForLabel:KVCell.userDescription withAttributedString:attr];
            [KVCellTweet laodUserDescription:attr];
            [KVCellTweet.userDescription updateConstraints];
            [KVCellTweet.userDescription layoutIfNeeded];

            [KVCellTweet loadTweets];

            [KVCellTweet performSelector:@selector(laodCellContents) onThread:[NSThread mainThread] withObject:nil waitUntilDone:TRUE];
            [KVCellTweet.contentView updateConstraints];
            [KVCellTweet.contentView layoutIfNeeded];
            [KVCellTweet layoutIfNeeded];
            [KVCellTweet updateConstraints];
            return KVCellTweet;

        } break;
        case EMBED_MUL_AUDIO: {
            NSLog(@"card type EMBED_MUL_AUDIO");
            [_postDict setObject:indexPath forKey:KEY_INDEXPATH];
            KVembedMultiAudio* KVCellAudio = (KVembedMultiAudio*)[tableView dequeueReusableCellWithIdentifier:@"EmbedMultiAudio" forIndexPath:indexPath];
            KVCellAudio.embededDetails = _postDict;
            [KVCellAudio setLikeDelegate:self];
            KVCellAudio.userDescription.preferredMaxLayoutWidth = _timeLineTableView.bounds.size.width -16;
            [KVCellAudio.userDescription setText:discription];
            NSAttributedString *attr = [CVUtilityManager UserDescription:discription];
            KVCellAudio.userDescrptionHeight.constant =[CVUtilityManager sizeForLabel:KVCell.userDescription withAttributedString:attr];
            [KVCellAudio laodUserDescription:attr];
            [KVCellAudio.userDescription updateConstraints];
            [KVCellAudio.userDescription setNeedsLayout];
            [KVCellAudio.userDescription layoutIfNeeded];
            [KVCellAudio performSelector:@selector(laodCellContents) onThread:[NSThread mainThread] withObject:nil waitUntilDone:true];
            [KVCellAudio.contentView layoutIfNeeded];
            return KVCellAudio;
        }
            break;

        default:
            break;
    }
    [KVCell updateConstraints];
    [KVCell layoutIfNeeded];
    return KVCell;
}


- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath;
{

    return UITableViewAutomaticDimension;

}

- (CGFloat)tableView:(UITableView *)tableView estimatedHeightForRowAtIndexPath:(NSIndexPath *)indexPath {
    NSNumber *height = [self.heightAtIndexPath objectForKey:indexPath];
    if(height) {
        return height.floatValue;
    } else {
        return UITableViewAutomaticDimension;
    }
}

【问题讨论】：

  • 将 web 服务调用和图像下载移动到后台线程，以便您的 tableview 平滑滚动
  • 在你的 tableView:cellForRowAtIndexPath: 方法中发生了很多事情。您应该尽快返回单元格。这篇文章会很有帮助medium.com/ios-os-x-development/…
  • @OstapHorbach 非常感谢.. 但是在哪里为我的单元格设置数据.. 因为我使用多个自定义单元格——我无法在 willdisplay 单元格方法中设置数据..任何建议

标签： ios objective-c uitableview vertical-scrolling


【解决方案1】：

您可以对自定义单元格使用子类化。由于您对每一行都有很多自定义项，因此您可以为每一行子类化您的基本单元类。

对于设置数据，您可以创建一个数据模型对象并在您的行类中创建它的一个实例。然后你可以从 cellforRowAtIndexpath 设置你的数据模型，比如

CustomRowCell *rowCell = [[CustomRowCell alloc] init];
rowCell.dataSource = [yourDictionary objectForKey:@"key"]// yourArray[indexPath.row];

还可以使用调度队列进行服务调用。

希望对你有帮助！

【讨论】：

  • 您好，感谢您的回答---我如何子类化自定义单元格...我不是已经这样做了..
  • 是的，我现在明白了。正如我所说，您必须在子类方法中移动所有自定义，例如在您的 init 方法中。
猜你喜欢
  • 2019-07-20
  • 2014-12-06
  • 2011-11-06
  • 1970-01-01
  • 1970-01-01
  • 1970-01-01
  • 1970-01-01
  • 1970-01-01
  • 1970-01-01
相关资源
最近更新 更多
热门标签
Java Python linux javascript Mysql C# Docker 算法 前端 SpringBoot Redis Vue spring 设计模式 .net core .net kubernetes c++ 数据库 数据结构 大数据 js 机器学习 微服务 Android Go 程序员 面试 JVM ASP.net core 云原生 人工智能 后端 PHP git CSS golang k8s Nginx Django mybatis 深度学习 多线程 React 架构 devops 爬虫 云计算 Spring Boot LeetCode