Question

I have a UITableView filled with cells that display file names, and the cells also indicate the upload/download progress of the files. When a file is being moved, its corresponding cell should show a UIActivityIndicatorView in its accessory view. I have a UIActivityIndicatorView set up and ready to go in viewDidLoad, but when I tried to set it as the accessory view for multiple cells, it only shows up in one cell.

-(void)viewDidLoad {

    [super viewDidLoad];

    activityIndicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
    [activityIndicator startAnimating];

}


//...code that detects file changes and calls fileChange


-(void)fileChange {

    for (int i = 0; i < [self.cloudNames count]; i++) {

        //detect whether file name in array is uploading, downloading, or doing nothing

        NSIndexPath *indexPath = [NSIndexPath indexPathForRow:i inSection:0];
        UITableViewCell *cell = [self.tableView cellForRowAtIndexPath:indexPath];

        if (downloading) {

            cell.accessoryView = activityIndicator;
            //other changes here specific to downloads

        } else if (uploading) {

            cell.accessoryView = activityIndicator;
            //other changes here specific to uploads

        } else {

            cell.accessoryView = nil;

        }

    }

}

As I said, the activity indicator only shows in one cell even where there are multiple cells that should show it.

I don’t want to set up the UIActivityIndicatorView in the fileChange method (even though it works) because this method is called many times during the upload/download. If the method is called and the activity indicator is set up there, the activity indicator resets in all of the table view cells when the method is called, resulting in glitchy and unsmooth animations, and it causes a huge memory problem.

Any ideas of what to do? Thanks.

Answer 1

Even if you are setting the activity indicator for the cell, you only ONE instance variable for it. The way to do this is to create an indicator for each cell inside tableView:cellForRowAtIndexPath:

You can set a tag for the UIActivityIndicatorView and whenever you want to access it or grab it you can get the cell, and get the indicator view using [cellView viewWithTag:theTag]. No need for instance variables.

If you want to make things even fancier you can subclass UITableViewCell and do whatever you want to do inside your custom cell..

EDIT:

To get the view you can either assign to the accessory view and just get the cells accessoryView:

 UITableViewCell *cell = [self.tableView cellForRowAtIndexPath:indexPath];

 UIActivityIndicatorView *indicator = (UIActivityIndicatorView *) cell.accessoryView;

or you can add the UIActivityIndicatorView to the cell`s contentView (that way you can place it where ever you want, you have more flexibility):

adding the indicator:

myIndicatorView.tag = 1;
[cell.contentView addSubview:myIndicatorView];

getting the indicator:

UIActivityIndicatorView *indicator = [cell.contentView viewWithTag:1];

hope this helps