iPhone UITableView. How do turn on the single letter alphabetical list like the Music App?

user_116169 0
Viewed 61753

In the iPhone music app, selecting Artist, Songs, or Albums presents a tableView with a verticl list of single letters at the righthand side of the UI that enables rapid scrolling. How do I enable this functionality in my app?

Cheers, Doug

objective-c uitableview iphone ios
9 Answers

Here is a modified version of Kyle's function that handles the case of clicking an index for which you do not have a string:

- (NSInteger)indexForFirstChar:(NSString *)character inArray:(NSArray *)array
{
    char testChar = [character characterAtIndex:0];
    __block int retIdx = 0;
    __block int lastIdx = 0;

    [array enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
        char firstChar = [obj characterAtIndex:0];

        if (testChar == firstChar) {
            retIdx = idx;
            *stop = YES;
        }

        //if we overshot the target, just use whatever previous one was
        if (testChar < firstChar) {
            retIdx = lastIdx;
            *stop = YES;
        }

        lastIdx = idx;
    }];
    return retIdx;
}
user_6021460
Related