UITableview Scroll erases data in text field insid

问题:

I have a UITableViewController with UITextfield inside the tableview cells. If I scroll the table view, the user entered data in the textfields disappears. I tried to add the textfield data to a NSMutableArray but it still didn't work. Any help please.

回答1:

When cellForRowAtIndexPath: is called, the cell you return has to be completely filled in with whatever data you want to show. So, if the cell includes a UITextfield, you'll need to set it's text property to the right value for that row in your data.

When a table cell disappears off the top or bottom of the screen, the UITableViewCell itself becomes available for re-use. (As you scroll, cells disappear, and new cells appear, but the UITableView class is re-using the UITableViewCell objects.) In cellForRowAtIndexPath: when you get a cached cell to use, you have to be sure to setup everything you want it to show for the row in question, otherwise you might see some odd behavior in your table.

Does this help?

EDIT:

Here's an example of the typical pattern used in cellForRowAtIndexPath:. Notice the use of dequeueReusableCellWithIdentifier:. That method returns a previously allocated but not in use UITableViewCell, if there is one. Notice further that if no cached cell is returned, the code creates a new one, and sets it up (with stuff that is independent of anything that might be row specific). Following that, you'd setup the cell as you need it for the row in question.

- (UITableViewCell *)tableView:(UITableView *)tableView 
    cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *SearchResultsCellIdentifier = @"SearchResultsCellIdentifer";

    UITableViewCell *cell = [tableView 
                dequeueReusableCellWithIdentifier:SearchResultsCellIdentifier];
    if (cell == nil)
    {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle
                       reuseIdentifier:SearchResultsCellIdentifier] autorelease];
        cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
    }

    // Your row-specific setup of the cell here
    // ...

    return cell;
}

Check the docs for specifics about these methods. There are LOTS of examples from Apple and elsewhere about how to implement tableViews.