在UITableView中动态添加行并设置scrollToRowAtIndexPath

Question

在点击索引路径n-3处的按钮时动态地添加行。在我的表视图中，默认情况下总共有6行，4个包含文本字段和另外两个包含按钮(添加更多和保存)。在最后两行以上的位置添加按钮。

-(void)addMoreButton:(UIButton *)sender
{
rowCount=rowCount+1;

int section = 0;
long row = rowCount;

NSIndexPath* path = [NSIndexPath indexPathForRow:row-3 inSection:section];

[(UITableView *)[self.view viewWithTag:ktagtableView_detailsEdit] beginUpdates];
[(UITableView *)[self.view viewWithTag:ktagtableView_detailsEdit] insertRowsAtIndexPaths:[NSArray arrayWithObjects:path, nil] withRowAnimation:UITableViewRowAnimationLeft];
[(UITableView *)[self.view viewWithTag:ktagtableView_detailsEdit] endUpdates];

    NSIndexPath* top = [NSIndexPath indexPathForRow:rowCount-1 inSection:0];
    [(UITableView*)[self.view viewWithTag:ktagtableView_detailsEdit] scrollToRowAtIndexPath:top atScrollPosition:UITableViewScrollPositionBottom animated:YES];   

}

当rowCount大于8时，调用scrollToRowAtIndexPath方法，然后调用cellForRowAtIndexPath方法两次，就会出现问题。第一次由传递索引n-3的insertRowAtIndex调用，第二次调用scrollToRowAtIndexPath时，它传递索引n-1，当

if (indexPath.row == rowCount-1)   //  This is index for last row that contains save button and this condition match thus instead of adding textfields it starts adding save button.


if (indexPath.row == rowCount-2)  //  This is Add more button.

if (indexPath.row < rowCount-2)  //  This is for adding textFields.

请为以上内容提供指导。如果有任何疑问，请随时询问。前两天我被困在里面了。

更新: cellForRowAtIndexPath方法。

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

NSString *CellIdentifier;
CellIdentifier = [NSString stringWithFormat:@"S%1dR%1d",indexPath.section,indexPath.row];
 UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier: CellIdentifier];

CellIdentifier = [NSString stringWithFormat:@"S%1dR%1d",indexPath.section,indexPath.row];
UITextField *textField_SocialProfile;
UIButton *button_AddMore, *button_AddToMyCon;

UIImageView *imageView_Add;

if(cell == nil)
{
    cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];


    [cell setSelectionStyle:UITableViewCellSelectionStyleNone];
    [cell setBackgroundColor:[UIColor clearColor]];

    linelable=[[UILabel alloc]initWithFrame:CGRectMake(0, cell.contentView.frame.size.height+9, cell.contentView.frame.size.width, 0.5)];
    [cell.contentView addSubview:linelable];
    [linelable setBackgroundColor:[UIColor colorWithRed:(152.0f/255.0f) green:(152.0f/255.0f) blue:(152.0f/255.0f) alpha:0.2f]];

    if (indexPath.row < rowCount-2)
    {
        textField_SocialProfile = [[UITextField alloc]init];
        textField_SocialProfile.tag=indexPath.row+501;
        NSLog(@"textField_SocialProfile.tag %ld",(long)textField_SocialProfile.tag);

        textField_SocialProfile.frame = CGRectMake(70, (tableView.rowHeight - 20)/2, 230, 30);
        textField_SocialProfile.delegate = self;
        textField_SocialProfile.borderStyle = UITextBorderStyleRoundedRect;

        switch (indexPath.row) {
            case 0:
                textField_SocialProfile.attributedPlaceholder = [[NSAttributedString alloc] initWithString:ktagInstagram attributes:@{NSForegroundColorAttributeName: [UIColor lightGrayColor]}];
                break;
            case 1:
                textField_SocialProfile.attributedPlaceholder = [[NSAttributedString alloc] initWithString:ktagFacebook attributes:@{NSForegroundColorAttributeName: [UIColor lightGrayColor]}];
                break;
            case 2:
                textField_SocialProfile.attributedPlaceholder = [[NSAttributedString alloc] initWithString:ktagTwitter attributes:@{NSForegroundColorAttributeName: [UIColor lightGrayColor]}];
                break;
            case 3:
                textField_SocialProfile.attributedPlaceholder = [[NSAttributedString alloc] initWithString:@"Linkedin" attributes:@{NSForegroundColorAttributeName: [UIColor lightGrayColor]}];
                break;
            default:
                textField_SocialProfile.attributedPlaceholder = [[NSAttributedString alloc] initWithString:@"Social Networking" attributes:@{NSForegroundColorAttributeName: [UIColor lightGrayColor]}];
        }

        textField_SocialProfile.textColor = [UIColor colorWithRed:(152.0f/255.0f) green:(152.0f/255.0f) blue:(152.0f/255.0f) alpha:1.0f];
        textField_SocialProfile.layer.cornerRadius = 5.0;
        textField_SocialProfile.clipsToBounds = YES;

        [textField_SocialProfile.layer setBorderColor:[UIColor lightGrayColor].CGColor];
        [textField_SocialProfile.layer setBorderWidth:0.5];


    if (intEditSave==1) {
        [textField_SocialProfile setUserInteractionEnabled:NO];
    }
    else
    {
        [textField_SocialProfile setUserInteractionEnabled:YES];
    }

        imageView_Add = [[UIImageView alloc]init];

        switch (indexPath.row) {
            case 0:
                imageView_Add.image = [UIImage imageNamed:@"instagramIcon.png"];
                textField_SocialProfile.text=@"www.instagram.com/";

                if (dataSourceArray.count > indexPath.row) {
                    textField_SocialProfile.text = [[dataSourceArray objectAtIndex:indexPath.row] objectForKey:@"SocialProfile"];
                    if ([[NSString stringWithFormat:@"%@",[[dataSourceArray objectAtIndex:indexPath.row] objectForKey:@"SocialProfile"]] length] != 0) {
                        textField_SocialProfile.text=[[dataSourceArray objectAtIndex:indexPath.row] objectForKey:@"SocialProfile"];
                         if([textField_SocialProfile.text isEqualToString:@""])
                        {
                            textField_SocialProfile.text=[NSString stringWithFormat:@"www.instagram.com/%@",[[dataSourceArray objectAtIndex:indexPath.row] objectForKey:@"SocialProfile"]];
                        }
                    }else{
                        textField_SocialProfile.text=@"www.instagram.com/";
                    }
                }

                break;
            case 1:
                imageView_Add.image = [UIImage imageNamed:@"facebokIcon.png"];
                textField_SocialProfile.text=@"www.facebook.com/";

                if (dataSourceArray.count > indexPath.row) {
                    textField_SocialProfile.text = [[dataSourceArray objectAtIndex:indexPath.row] objectForKey:@"SocialProfile"];
                    if ([[NSString stringWithFormat:@"%@",[[dataSourceArray objectAtIndex:indexPath.row] objectForKey:@"SocialProfile"]] length] != 0) {
                        textField_SocialProfile.text=[[dataSourceArray objectAtIndex:indexPath.row] objectForKey:@"SocialProfile"];
                        if([textField_SocialProfile.text isEqualToString:@""])
                        {
                            textField_SocialProfile.text=[NSString stringWithFormat:@"www.facebook.com/%@",[[dataSourceArray objectAtIndex:indexPath.row] objectForKey:@"SocialProfile"]];
                        }
                    }else{
                        textField_SocialProfile.text=@"www.facebook.com/";
                    }
                }                    break;
            case 2:
                imageView_Add.image = [UIImage imageNamed:@"twitterIcon.png"];
                textField_SocialProfile.text=@"www.twitter.com/";

                if (dataSourceArray.count > indexPath.row) {
                    textField_SocialProfile.text = [[dataSourceArray objectAtIndex:indexPath.row] objectForKey:@"SocialProfile"];
                    if ([[NSString stringWithFormat:@"%@",[[dataSourceArray objectAtIndex:indexPath.row] objectForKey:@"SocialProfile"]] length] != 0) {
                        textField_SocialProfile.text=[[dataSourceArray objectAtIndex:indexPath.row] objectForKey:@"SocialProfile"];
                         if([textField_SocialProfile.text isEqualToString:@""])
                        {
                            textField_SocialProfile.text=[NSString stringWithFormat:@"www.twitter.com/%@",[[dataSourceArray objectAtIndex:indexPath.row] objectForKey:@"SocialProfile"]];
                        }
                    }else{
                        textField_SocialProfile.text=@"www.twitter.com/";
                    }
                }                    break;
            case 3:
                imageView_Add.image = [UIImage imageNamed:@"linkedinIcon.png"];
                textField_SocialProfile.text=@"www.linkedin.com/";

                if (dataSourceArray.count > indexPath.row) {
                    textField_SocialProfile.text = [[dataSourceArray objectAtIndex:indexPath.row] objectForKey:@"SocialProfile"];
                    if ([[NSString stringWithFormat:@"%@",[[dataSourceArray objectAtIndex:indexPath.row] objectForKey:@"SocialProfile"]] length] != 0) {
                        textField_SocialProfile.text=[[dataSourceArray objectAtIndex:indexPath.row] objectForKey:@"SocialProfile"];
                         if([textField_SocialProfile.text isEqualToString:@""])
                        {
                            textField_SocialProfile.text=[NSString stringWithFormat:@"www.linkedin.com/%@",[[dataSourceArray objectAtIndex:indexPath.row] objectForKey:@"SocialProfile"]];
                        }
                    }else{
                        textField_SocialProfile.text=@"www.linkedin.com/";
                    }
                }                    break;
            default:
                imageView_Add.image = [UIImage imageNamed:@"myconIcon.png"];
                if (dataSourceArray.count > indexPath.row) {

                    textField_SocialProfile.text = [[dataSourceArray objectAtIndex:indexPath.row] objectForKey:@"SocialProfile"];}

                break;

        }

        NSString *socialName= textField_SocialProfile.text;


        switch (indexPath.row) {
            case 0:
                if ([socialName rangeOfString:@"www.instagram.com/"].location!=NSNotFound) {
                    imageView_Add.image = [UIImage imageNamed:@"instagramIcon.png"];
                }
                else if ([socialName rangeOfString:@"www.linkedin.com/"].location!=NSNotFound)
                {
                    imageView_Add.image = [UIImage imageNamed:@"linkedinIcon.png"];
                }
                else if ([socialName rangeOfString:@"www.facebook.com/"].location!=NSNotFound)
                {
                    imageView_Add.image = [UIImage imageNamed:@"facebokIcon.png"];
                }
                else if ([socialName rangeOfString:@"www.twitter.com/"].location!=NSNotFound)
                {
                    imageView_Add.image = [UIImage imageNamed:@"twitterIcon.png"];
                }
                else
                {
                    imageView_Add.image = [UIImage imageNamed:@"myconIcon.png"];
                }

                break;
            case 1:
                if ([socialName rangeOfString:@"www.instagram.com/"].location!=NSNotFound) {
                    imageView_Add.image = [UIImage imageNamed:@"instagramIcon.png"];
                }
                else if ([socialName rangeOfString:@"www.linkedin.com/"].location!=NSNotFound)
                {
                    imageView_Add.image = [UIImage imageNamed:@"linkedinIcon.png"];

                }
                else if ([socialName rangeOfString:@"www.facebook.com/"].location!=NSNotFound)
                {
                    imageView_Add.image = [UIImage imageNamed:@"facebokIcon.png"];

                }
                else if ([socialName rangeOfString:@"www.twitter.com/"].location!=NSNotFound)
                {
                    imageView_Add.image = [UIImage imageNamed:@"twitterIcon.png"];

                }
                else
                {
                    imageView_Add.image = [UIImage imageNamed:@"myconIcon.png"];
                }
                break;
            case 2:
                if ([socialName rangeOfString:@"www.instagram.com/"].location!=NSNotFound) {
                    imageView_Add.image = [UIImage imageNamed:@"instagramIcon.png"];
                }
                else if ([socialName rangeOfString:@"www.linkedin.com/"].location!=NSNotFound)
                {
                    imageView_Add.image = [UIImage imageNamed:@"linkedinIcon.png"];
                }
                else if ([socialName rangeOfString:@"www.facebook.com/"].location!=NSNotFound)
                {
                    imageView_Add.image = [UIImage imageNamed:@"facebokIcon.png"];

                }
                else if ([socialName rangeOfString:@"www.twitter.com/"].location!=NSNotFound)
                {
                    imageView_Add.image = [UIImage imageNamed:@"twitterIcon.png"];

                }
                else
                {
                    imageView_Add.image = [UIImage imageNamed:@"myconIcon.png"];
                }
                break;
            case 3:
                if ([socialName rangeOfString:@"www.instagram.com/"].location!=NSNotFound) {
                    imageView_Add.image = [UIImage imageNamed:@"instagramIcon.png"];
                }
                else if ([socialName rangeOfString:@"www.linkedin.com/"].location!=NSNotFound)
                {
                    imageView_Add.image = [UIImage imageNamed:@"linkedinIcon.png"];

                }
                else if ([socialName rangeOfString:@"www.facebook.com/"].location!=NSNotFound)
                {
                    imageView_Add.image = [UIImage imageNamed:@"facebokIcon.png"];

                }
                else if ([socialName rangeOfString:@"www.twitter.com/"].location!=NSNotFound)
                {
                    imageView_Add.image = [UIImage imageNamed:@"twitterIcon.png"];
                }
                else
                {
                    imageView_Add.image = [UIImage imageNamed:@"myconIcon.png"];
                }
                break;
            default:
                if ([socialName rangeOfString:@"www.instagram.com/"].location!=NSNotFound) {
                    imageView_Add.image = [UIImage imageNamed:@"instagramIcon.png"];
                }
                else if ([socialName rangeOfString:@"www.linkedin.com/"].location!=NSNotFound)
                {
                    imageView_Add.image = [UIImage imageNamed:@"linkedinIcon.png"];

                }
                else if ([socialName rangeOfString:@"www.facebook.com/"].location!=NSNotFound)
                {
                    imageView_Add.image = [UIImage imageNamed:@"facebokIcon.png"];

                }
                else if ([socialName rangeOfString:@"www.twitter.com/"].location!=NSNotFound)
                {
                    imageView_Add.image = [UIImage imageNamed:@"twitterIcon.png"];
                }
                else
                {
                    imageView_Add.image = [UIImage imageNamed:@"myconIcon.png"];
                }
                break;
        }


        imageView_Add.frame = CGRectMake(30, (tableView.rowHeight - 8)/2, 15, 15);
        textField_SocialProfile.font = [UIFont fontWithName:@"arial" size:15.0];

        [cell addSubview:imageView_Add];
        imageView_Add = Nil;
        [cell addSubview:textField_SocialProfile];
        //textField_SocialProfile = Nil;

    }

    else if(indexPath.row == rowCount-2)//Add more button
    {
        //        NSLog(@"textf: %@",textF.text);

        NSLog(@"AddMore: %ld",indexPath.row);
        NSLog(@"AddMore: %d",rowCount);

        button_AddMore = [[UIButton alloc]init];
        [button_AddMore setTitle:ktagAdd_More forState:UIControlStateNormal];
        [button_AddMore titleLabel].font = [UIFont fontWithName:@"arial" size:15.0];
        [button_AddMore setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
        [button_AddMore addTarget:self action:@selector(addMoreButton:) forControlEvents:UIControlEventTouchUpInside];
        button_AddMore.tag = ktagbutton_AddMore;

        button_AddMore.frame = CGRectMake(90, (cell.frame.size.height-20)/2, 140, 30);
        button_AddMore.center=CGPointMake(90+70, 22);
        [button_AddMore setBackgroundImage:[UIImage imageNamed:@"addMore_button.png"] forState:UIControlStateNormal];
        [cell addSubview:button_AddMore];
        linelable.hidden=NO;

        if(intEditSave == 1)//Editing is complete
        {
            button_AddMore.enabled=NO;
        }
        else
        {
            button_AddMore.enabled=YES;
        }
    }
    else if(indexPath.row == rowCount-1)//Save fields button
    {
        NSLog(@"Save: %ld",indexPath.row);
        NSLog(@"Save: %d",rowCount);

        button_AddToMyCon = [[UIButton alloc]init];
        [button_AddToMyCon setTitle:ktagAdd_to_MyCon forState:UIControlStateNormal];
        [button_AddToMyCon titleLabel].font = [UIFont fontWithName:@"arial" size:15.0];
        [button_AddToMyCon setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
        [button_AddToMyCon addTarget:self action:@selector(save_Fields:) forControlEvents:UIControlEventTouchUpInside];
        button_AddToMyCon.tag = ktagbutton_AddToMyCon;

        button_AddToMyCon.frame = CGRectMake(90, (cell.frame.size.height-20)/2, 140, 30);
        button_AddToMyCon.center=CGPointMake(90+70, 22);

        [button_AddToMyCon setBackgroundColor:[UIColor colorWithRed:(234.0f/255.0f) green:(134.0f/255.0f) blue:(59.0f/255.0f) alpha:1.0]];
        button_AddToMyCon.layer.cornerRadius=4;
        [cell addSubview:button_AddToMyCon];
        linelable.hidden=YES;

    }

}
    return cell;
}

问题是，如果我将dequeReusable属性设置为nil，那么这个问题就解决了，当前数据开始在滚动时消失。

Answer 1

这是tableView数据源和委托方法的一种行为。当scrollToRowAtIndexPath时调用cellForRowAtIndexPath方法，因为当表格滚动显示屏幕上不可见的单元格时，该方法执行重用单元格，因此cellForRowAtIndexPath为新的可见单元格加载内容。

这是默认和正确的行为，您不能绕过它。

现在，您需要使用它来管理应用程序需求。我不这样认为，这种行为对你的需求有任何漏洞。

因为cellForRowAtIndexPath是一个被多次调用的方法，您在这里不能限制任何约束。如果你认为你的预期行为没有实现，请留下评论。

编辑：

在为你创建一个示例演示的同时，我想出了一点--它可能会很快解决你的问题。

在下面的代码行中，动画无法正常工作：

[(UITableView *)[self.view viewWithTag:ktagtableView_detailsEdit] insertRowsAtIndexPaths:[NSArray arrayWithObjects:path, nil] withRowAnimation:UITableViewRowAnimationLeft];

将行动画UITableViewRowAnimationLeft改为UITableViewRowAnimationAutomatic，请参见下面的更新行：

[(UITableView *)[self.view viewWithTag:ktagtableView_detailsEdit] insertRowsAtIndexPaths:[NSArray arrayWithObjects:indexPath, nil] withRowAnimation:UITableViewRowAnimationAutomatic];

不过，如果这不能解决您的问题，您可以在这里提供示例演示。

为了简单起见，我使用了限制控制，并将重点放在功能上。

Dynamic Cell Creation Demo - Click Here

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