滚动时，一个单元格的内容在下一个单元格中重复。这些单元格是自定义单元格。

    static NSString *cellIdentifier1 = @"pollCell";
    IXPollCustomCell *pollCell = (IXPollCustomCell *)[tableView dequeueReusableCellWithIdentifier:cellIdentifier1];
    if (pollCell == nil) {
        pollCell = [[[NSBundle mainBundle] loadNibNamed:@"IXPollCustomCell" owner:self options:nil] objectAtIndex:0];
        pollCell.selectionStyle = UITableViewCellSelectionStyleNone;
    }
    [self configurePollCell:pollCell atIndexPath:indexPath];//custom cell configuration

如何防止 subview 内容重复？

编辑:- 我在此处包含了 configurePollCell 函数。

-(void)configurePollCell:(IXPollCustomCell*)cell atIndexPath:(NSIndexPath *)indexPath
{

 ThreadInfo *info = [_fetchedResultsController objectAtIndexPath:indexPath];
 if([info.pollType isEqualToString:@"Star"])
    {
        cell.multiChoiceView.hidden=YES;
        cell.starView.hidden=NO;
        UIImage *blackStarImage=[[UIImage alloc]initWithContentsOfFile:[[NSBundle mainBundle]pathForResource:@"star_orange" ofType:@"png"]];
        UIImage *whiteStarImage=[[UIImage alloc]initWithContentsOfFile:[[NSBundle mainBundle]pathForResource:@"star_white" ofType:@"png"]];


        cell.star1ImageView.image=whiteStarImage;
        cell.star2ImageView.image=whiteStarImage;
        cell.star3ImageView.image=whiteStarImage;
        cell.star4ImageView.image=whiteStarImage;
        cell.star5ImageView.image=whiteStarImage;

        cell.selectedStar1ImageView.hidden=YES;
        cell.selectedStar2ImageView.hidden=YES;
        cell.selectedStar3ImageView.hidden=YES;
        cell.selectedStar4ImageView.hidden=YES;
        cell.selectedStar5ImageView.hidden=YES;

        cell.averageLabel.text=@"";
        //Coloring
        BOOL isStarColoringRequired=NO;
        if([info.isPollSender boolValue])
        {
            if ([info.pollScope isEqualToString:@"private"])
            {
                if([info.responseCount integerValue]>=2)
                {
                    isStarColoringRequired=YES;

                }
            }
            else
            {
                isStarColoringRequired=YES;

            }
        }
        else
        {

            if ([info.pollScope isEqualToString:@"private"])
            {
                if([info.pollVisibility isEqualToString:@"public"])
                {
                    if((info.selectedStar!=nil && [info.replied boolValue] )&&[info.responseCount integerValue]>=2)
                    {
                        isStarColoringRequired=YES;
                    }
                }
            }

            else
            {
                if(info.selectedStar!=nil && [info.replied boolValue])
                {
                    isStarColoringRequired=YES;
                }
            }
        }



        if(isStarColoringRequired)
        {
            if(ansDict!=nil)
            {
                double maxHeight= cell.star1ImageView.frame.size.height;
                double maxWidth=  cell.star1ImageView.frame.size.width;

                int star1Value=[[ansDict valueForKey:@"star1"] intValue];
                int star2Value=[[ansDict valueForKey:@"star2"] intValue];
                int star3Value=[[ansDict valueForKey:@"star3"] intValue];
                int star4Value=[[ansDict valueForKey:@"star4"] intValue];
                int star5Value=[[ansDict valueForKey:@"star5"] intValue];

                NSInteger total=[info.responseCount integerValue];
                if(total!=0)
                {
                    float star1Per=(float)star1Value/total;
                    float star2Per=(float)star2Value/total;
                    float star3Per=(float)star3Value/total;
                    float star4Per=(float)star4Value/total;
                    float star5Per=(float)star5Value/total;

                    float averageScore=(star1Value+star2Value*2+star3Value*3+star4Value*4+star5Value*5)/(float)total;
                    cell.averageLabel.text=[NSString stringWithFormat:@"Average Score - %.2f",averageScore];

                    CGFloat star1Y=maxHeight-(star1Per * maxHeight);
                    CGRect star1Rect = CGRectMake(0,star1Y,maxWidth,star1Per * maxHeight );

                    CGImageRef imageRef1 = CGImageCreateWithImageInRect([blackStarImage CGImage], star1Rect);
                    UIImage *croppedImage1 = [UIImage imageWithCGImage:imageRef1];
                    CGImageRelease(imageRef1);
                    cell.color1ImageView.frame=star1Rect;
                    cell.color1ImageView.image=nil;
                    cell.color1ImageView.image=croppedImage1;

                    CGFloat star2Y=maxHeight-(star2Per * maxHeight);
                    CGRect star2Rect = CGRectMake(0,star2Y,maxWidth,star2Per * maxHeight );
                    CGImageRef imageRef2 = CGImageCreateWithImageInRect([blackStarImage CGImage], star2Rect);
                    UIImage *croppedImage2 = [UIImage imageWithCGImage:imageRef2];
                    CGImageRelease(imageRef2);
                    cell.color2ImageView.frame=star2Rect;
                    cell.color2ImageView.image=nil;
                    cell.color2ImageView.image=croppedImage2;

                    CGFloat star3Y=maxHeight-(star3Per * maxHeight);
                    CGRect star3Rect = CGRectMake(0,star3Y,maxWidth,star3Per * maxHeight );

                    CGImageRef imageRef3 = CGImageCreateWithImageInRect([blackStarImage CGImage], star3Rect);
                    UIImage *croppedImage3 = [UIImage imageWithCGImage:imageRef3];
                    CGImageRelease(imageRef3);
                    cell.color3ImageView.frame=star3Rect;
                    cell.color3ImageView.image=nil;
                    cell.color3ImageView.image=croppedImage3;

                    CGFloat star4Y=maxHeight-(star4Per * maxHeight);
                    CGRect star4Rect = CGRectMake(0,star4Y,maxWidth,star4Per * maxHeight );
                    CGImageRef imageRef4 = CGImageCreateWithImageInRect([blackStarImage CGImage], star4Rect);
                    UIImage *croppedImage4 = [UIImage imageWithCGImage:imageRef4];
                    CGImageRelease(imageRef4);
                    cell.color4ImageView.frame=star4Rect;
                    cell.color4ImageView.image=nil;
                    cell.color4ImageView.image=croppedImage4;

                    CGFloat star5Y=maxHeight-(star5Per * maxHeight);
                    CGRect star5Rect = CGRectMake(0,star5Y,maxWidth,star5Per * maxHeight );

                    CGImageRef imageRef5 = CGImageCreateWithImageInRect([blackStarImage CGImage], star5Rect);
                    UIImage *croppedImage5 = [UIImage imageWithCGImage:imageRef5];
                    CGImageRelease(imageRef5);
                    cell.color5ImageView.frame=star5Rect;
                    cell.color5ImageView.image=nil;
                    cell.color5ImageView.image=croppedImage5;


                }

            }
        }


        int selectedStarCount=[info.selectedStar intValue];

        if([info.pollVisibility isEqualToString:@"private"])
        {

            switch (selectedStarCount) {
                case 1:
                    cell.selectedStar1ImageView.hidden=NO;

                    break;

                case 2:
                    cell.selectedStar2ImageView.hidden=NO;


                    break;
                case 3:
                    cell.selectedStar3ImageView.hidden=NO;


                    break;
                case 4:
                    cell.selectedStar4ImageView.hidden=NO;


                    break;
                case 5:
                    cell.selectedStar5ImageView.hidden=NO;

                    break;
                default:
                    break;
            }

        }
        else
        {
            if(info.selectedStar!=nil)
            {
                switch (selectedStarCount) {
                    case 1:
                        cell.selectedStar1ImageView.hidden=NO;

                        break;

                    case 2:
                        cell.selectedStar2ImageView.hidden=NO;

                        break;
                    case 3:
                        cell.selectedStar3ImageView.hidden=NO;

                        break;
                    case 4:

                        cell.selectedStar4ImageView.hidden=NO;

                        break;
                    case 5:

                        cell.selectedStar5ImageView.hidden=NO;

                        break;
                    default:
                        break;
                }

            }
        }
        if(info.image !=nil)
        {
            CGRect addFrame = cell.starView.frame;
            if (info.threadMessage.length > 100){
                addFrame.origin.y = 178 + 240;

            } else {
                addFrame.origin.y = 178 + 220;

            }

            cell.starView.frame = addFrame;
        } else {
            CGRect addFrame = cell.starView.frame;

            cell.starView.frame = CGRectMake(0,  ((0.8* self.view.frame.size.height)-10) / 2 +40, addFrame.size.width, 73);

        }

    }
}

最佳答案

您可以在子类中实现 prepareForReuse 方法并在那里进行清理。当您将 subview 添加到单元格时，它会保留在那里，直到您更改/删除它。

dequeueReusableCell 仅在可能的情况下为您提供一个单元格，它不会对单元格本身进行任何清理。

所以如果我有例如:

MyCustomCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if (!cell)
{
    cell = [[MyCustomCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier: dequeueReusableCellWithIdentifier:cellIdentifier];
    static dispatch_once_t onceToken = 0;
    dispatch_once(&onceToken, ^{
        UIView *testView = [[UIView alloc] initWithFrame:CGRectMake(20, 20, 20, 20);
        testView.tag = 20;
        testView.backgroundColor = UIColor.redColor;
        [cell.contentView addSubview:testView];
    });
}

cell.textLabel.text = @(indexPath.row).stringValue;

return cell;

当我向下滚动时，红色 subview 将出现在每个第 n 个单元格中。如果我标记 View 并实现 prepareForReuse，我可以删除 View 。

- (void)prepareForReuse
{
    [[self.contentView viewWithTag:20] removeFromSuperview]; //Does not crash if the view is nil. It's okay to send messages to nil in ObjC
}

在这种情况下，当我向下滚动时，我的红色 View 将消失。因此，您的问题的解决方案是您需要为每个单元格初始化添加一次 subview ，然后在单元格出列时管理它们。我希望这能解决问题。

关于ios - 使用 dequeueReusableCellWithIdentifier 时未清除 UITableView 自定义单元格的 subview 内容，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/29745482/