Question

Let’s say I have 10 tableViews that all need to have the first cell’s background , in all sections , color set to red.

In order not to do that manually for all the 10 table views I’m thinking that I should subclass UITableView.

My question would be: what should I overwrite from UITableView?

Or should I subclass UITableViewCell and all cells inherit from here?

Thanks.

Answer 1

You can subclass UITableViewCell and then you will have to somehow give the section&row to the cell so that it knows to set the background.

However, you can also subclass UITableView. Below is a solution if you choose to subclass UITableView, but in the end it’s your decision.

The only way I can think of right now is to somehow catch all requests to the tableView data source so that you can then manipulate the results.

You can do it like this:

• Subclass UITableView, let’s call it MyUITableView like this:

• Add a member variable id<UITableViewDataSource> myDataSource, and also a property for this variable with IBOutlet set to it. Then in Interface Builder, you should connect the table view using this property instead of the standard uitableview datasource property.

• Somewhere in the init or loadView, write self.dataSource = self. The idea is to catch all requests (expecially cellForRowAtIndexPath) so that you can manipulate the actual results.

• In your subclass, implement the UITableViewDataSource protocol, and just forward all calls to the myDataSource object.

• The only exception is in the cellForRowAtIndexPath implementation where after you get the result from myDataSource, you can change the background color if a specific condition is met. See an example code below

@interface MyUITableView : UITableView {
id<UITableViewDataSource> myDataSource;
}

@property (nonatomic, retain) IBOutlet id<UITableViewDataSource> myDataSource;

@end

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    // Get the result from the actual data source
    UITableViewCell* cell = nil;
    if (myDataSource)
        cell = [myDataSource tableView:self cellForRowAtIndexPath:indexPath];

    // If you condition is met, then just modify the cell in some way
    if (indexPath.section == 0 && indexPath.row == 0)
        cell.contentView.backgroundColor = [UIColor redColor];

    return cell;
}

And this is pretty much all you need. I don't know if I was clear enough, but if you have any questions don't hesitate.