展开部分UITableview when when reloadSections

Question

尝试展开部分展开时，每个部分将有两行。它正在让人崩溃。下面是我正在尝试的代码。

-(NSInteger) numberOfSectionsInTableView:(UITableView *)tableView
{
return [self.mArrQues count];
}

-(NSInteger) tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
if(!helpOn)
    return 1;
else
    if(section == selectedCellIndexPath)
    {
    return 2;
    }
    else{
        return 1;
    }
return 1;
}

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *cellIdentifier = @"CellIdentifier";
UITableViewCell *cell;
cell = [self.mHelpTable dequeueReusableCellWithIdentifier:cellIdentifier];
if (cell == nil) {
    cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
}
else{
    cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
}

UIView* myBackgroundView = [[UIView alloc] initWithFrame:CGRectZero];
myBackgroundView.backgroundColor = [UIColor colorWithRed:240.0/255.0 green:240.0/255.0 blue:240.0/255.0 alpha:1.0];
cell.backgroundView = myBackgroundView;
//[cell addSubview:myBackgroundView];

if(!helpOn)
{
    cell.textLabel.text = [self.mArrQues objectAtIndex:indexPath.section];
}
else
{
if(indexPath.row == 0)
    {
    cell.textLabel.text = [self.mArrQues objectAtIndex:indexPath.section];
    }
else{
    cell.textLabel.text = [self.mArrAns objectAtIndex:indexPath.section];
    }
}

cell.selectionStyle = UITableViewCellSelectionStyleNone;
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;

return cell;
}

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
helpOn = !helpOn;

int ind = indexPath.section;
if(ind == selectedCellIndexPath)
{
}
else{
    helpOn = 1;
}
if(helpOn)
{
    selectedCellIndexPath = indexPath.section;
[self.mHelpTable reloadSections:[NSIndexSet indexSetWithIndex:indexPath.section] withRowAnimation:UITableViewRowAnimationFade];
}
else
{
    if(indexPath.row == 0)
    {
    //selectedCellIndexPath = indexPath.section;
    [self.mHelpTable reloadSections:[NSIndexSet indexSetWithIndex:indexPath.section] withRowAnimation:UITableViewRowAnimationFade];
    }
}
}

错误：

Invalid update: invalid number of rows in section 0. The number of rows contained in an existing section after the update (2) must be equal to the number of rows contained in that section before the update (1), plus or minus the number of rows inserted or deleted from that section (0 inserted, 0 deleted) and plus or minus the number of rows moved into or out of that section (0 moved in, 0 moved out).'

Answer 1

当您更改部分中的单元格数量时，需要使用beginUpdates和endUpdates包装重载操作，并使用insertRowsAtIndexPaths:withRowAnimation和deleteRowsAtIndexPaths:withRowAnimation:指定单元格的插入和删除。

或者你可以使用'reloadData`来重新加载所有的单元格，但是如果你使用它，无论是动画还是用户体验都会有问题。

Answer 2

将其从您的代码中删除。

else{
    cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
}

如果单元格为nil，则不需要分配单元格，tableview将重用该行中的前一个单元格

cell = [self.mHelpTable dequeueReusableCellWithIdentifier:cellIdentifier];  

和

在.h中制造

int selectedCellIndexPath;
BOOL selected;

在.m中

-(NSInteger) tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{    
    if (section==selectedCellIndexPath)
    {
        //selected > this is because initialy selectedCellIndexPath is 0 and section is also 0
        if (selected) {
        return 2;
        }
        else{
            return 1;
        }
    }
    else{
        return 1;
    }
    return 1;
}

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *cellIdentifier = @"CellIdentifier";
    UITableViewCell *cell;
    cell = [self.mHelpTable dequeueReusableCellWithIdentifier:cellIdentifier];
    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
    }

    UIView* myBackgroundView = [[UIView alloc] initWithFrame:CGRectZero];
    myBackgroundView.backgroundColor = [UIColor colorWithRed:240.0/255.0 green:240.0/255.0 blue:240.0/255.0 alpha:1.0];
    cell.backgroundView = myBackgroundView;
    //[cell addSubview:myBackgroundView];

    //if(!helpOn)
    if (indexPath.section!=selectedCellIndexPath)
    {
        cell.textLabel.text = [mArrQues objectAtIndex:indexPath.section];
    }
    else
    {
        if(indexPath.row == 0)
        {
            cell.textLabel.text = [mArrQues objectAtIndex:indexPath.section];
        }
        else{
            cell.textLabel.text = [mArrAns objectAtIndex:indexPath.section];
        }
    }

    //cell.textLabel.text = [self.mArrQues objectAtIndex:indexPath.section];
    cell.selectionStyle = UITableViewCellSelectionStyleNone;
    cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;

    return cell;
}

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    selected= !selected;
    selectedCellIndexPath = indexPath.section;
    //selectedCellIndexPath = indexPath.row;
    [self.mHelpTable reloadSections:[NSIndexSet indexSetWithIndex:indexPath.section] withRowAnimation:UITableViewRowAnimationFade];

}