Question

Though this is one of the most asked question but i could not find one comprehensive answer. I need to have custom cells in UITableView. Some containing labels or text fields and some with images and buttons. I have made separate classes for each type of cell. I am using GroupStyle table with multiple sections. Right now I am adding cells in cellForIndexPath with switch-case for section and if-else for rows in section:

id cell;
switch(indexPath.section) {
    case 0:
           if(indexPath.row==0) {
               CellA *cell = [[[CellA alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:[NSString stringWithFormat:@"Celld%",indexPath.row]] autorelease];
               //configure cell
               return cell;
           }
           else if(indexPath.row==1) {
               CellB *cell = [[[CellB alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:[NSString stringWithFormat:@"Celld%",indexPath.row]] autorelease];
               //configure cell
               return cell;
           }
           break;
    case 1:
           if(indexPath.row==0) {
               CellC *cell = [[[CellC alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:[NSString stringWithFormat:@"Celld%",indexPath.row]] autorelease];
               //configure cell
               return cell;
           }
           break;
    default:
            break;
}
return cell;

I have to return cell at the end as well because due to definition of cells inside code blocks, cell becomes unrecognizable. To solve it, i declared cell with id on top.But i know this is not the right way. How can I resolve this declare and access issue of multiple types of cells?

There are 4-5 rows at the moment which fit one screen and do not need scrolling. So, I am not reusing cells. But more rows will squeeze in while editing. And in another table, there are more rows which can scroll of the screen. This means I must reuse cells. So, second part of my question is; how can I reuse multiple custom cells?

Answer 1

To answer your first question, you may as well return nil as you have no good value to return. If it ever hits this case, an exception will be thrown; as it is now, it s likely to give you an EXC_BAD_ACCESS somewhere inside the framework code.

To answer your second question, each type of cell should have a unique reuseIdentifier. For example, all the CellA s could have a reuseIdentifier of @"CellA". Then you would reuse them exactly as you would in the case that all the cells were the same: when you need a CellA call [tableView dequeueReusableCellWithIdentifier:@"CellA"], when you need a CellB call [tableView dequeueReusableCellWithIdentifier:@"CellB"], and so on. For example,

    case 0:
        if (indexPath.row == 0) {
            CellA *cell = [tableView dequeueReusableCellWithIdentifier:@"CellA"];
            if (!cell) {
                cell = [[[CellA alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"CellA"] autorelease];
            }
            // configure cell
            return cell;
        }
        else if (indexPath.row == 1) {
            CellB *cell = [tableView dequeueReusableCellWithIdentifier:@"CellB"];
            if (!cell) {
                cell = [[[CellB alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"CellB"] autorelease];
            }
            // configure cell
            return cell;
        }
        break;
    case 1:
        if (indexPath.row == 0) {
            CellC *cell = [tableView dequeueReusableCellWithIdentifier:@"CellC"];
            if (!cell) {
                cell = [[[CellC alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"CellC"] autorelease];
            }
            // configure cell
            return cell;
        }
        break;

Answer 2

Add UITableView To UIView.Add custom cells, associate custom cell classes and implement delegates -UITableviewDelegate and UITableViewDataSource .

case 1: Two custom cells on tableview

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

  var cell: CustomCell!

  if indexPath.row == 0{
    cell = tableView.dequeueReusableCellWithIdentifier("Cell1ID", forIndexPath: indexPath) as CustomCell
    //set cell2
  }
  if indexPath.row >= 1{
    cell = tableView.dequeueReusableCellWithIdentifier("Cell2ID", forIndexPath: indexPath) as CustomCell
    let cons = aArray[indexPath.row - 1]
    // set cell2 
  }
  return cell
}

case 2: alternate display of custom cells (i.e. using uisegmentcontrol)

var CellIdentifier: String = "Cell1ID"

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
       if (CellIdentifier == "Cell1ID")
    {
let cell = tableView.dequeueReusableCellWithIdentifier(CellIdentifier)! as! FirstTableViewCell

//additional code
return cell

}
else {
let cell = tableView.dequeueReusableCellWithIdentifier(CellIdentifier)! as! SecondTableViewReportsCell

//Additional code

return cell
}
}

case 3: Alternate custom cells (i.e., odd even)

var CellIdentifier: String = "Cell1ID"

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

var cell: CustomCell!

if (indexPath.row % 2 == 0) {

let cell = tableView.dequeueReusableCellWithIdentifier(CellIdentifier)! as! FirstTableViewCell
   
}
else
{
        let cell = tableView.dequeueReusableCellWithIdentifier(CellIdentifier)! as! SecondTableViewCell
}
return cell
}

友情链接