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iOS

Posted by Robert Conti
Robert Conti
23,274 Points

iOS: deselectRowAtIndexPath method not working

In the Self-Destructing MSG App project in the iOS track, the 'deselectRowAtIndexPath' method is called when adding/removing friends. Also, a checkmark is either shown or hidden next to each username to indicate that they have been added or removed. For some reason, when tapping on a username in the 'Edit Friends' View Controller, the username stays highlighted and the checkmark does not appear/disappear until another username is tapped. So essentially, 'deselectRowAtIndexPath' is not working. Suggestions?

- (void)tableView:(UITableView *)tableView didDeselectRowAtIndexPath:(NSIndexPath *)indexPath {
    [self.tableView deselectRowAtIndexPath:indexPath animated:NO];

    UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];

    PFUser *user = [self.allUsers objectAtIndex:indexPath.row];
    PFRelation *friendsRelation = [self.currentUser relationForKey:@"friendsRelation"];

    if ([self isFriend:user]) {
        cell.accessoryType = UITableViewCellAccessoryNone;              //1. Remove Checkmark

        for (PFUser *friend in self.friends) {                          //2. Remove from the array of friends
            if ([friend.objectId isEqualToString:user.objectId]) {
                [self.friends removeObject:friend];
                break;
            }
        }
        [friendsRelation removeObject:user];                            //3. Remove from the backend
    }
    else {
        cell.accessoryType = UITableViewCellAccessoryCheckmark;
        [self.friends addObject:user];
        [friendsRelation addObject:user];
    }

    [self.currentUser saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
        if (error) {
            NSLog(@"Error %@ %@", error, [error userInfo]);
        }
    }];
}

1 Answer

Stone Preston
Stone Preston
42,016 Points

you implemented the wrong method. you implemented didDeselectRowAtIndexPath, you need to implement didSelectRowAtIndexPath. replace what you have with 

//implement didSelectRow, not didDeselectRow

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    [self.tableView deselectRowAtIndexPath:indexPath animated:NO];

    UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];

    PFUser *user = [self.allUsers objectAtIndex:indexPath.row];
    PFRelation *friendsRelation = [self.currentUser relationForKey:@"friendsRelation"];

    if ([self isFriend:user]) {
        cell.accessoryType = UITableViewCellAccessoryNone;              //1. Remove Checkmark

        for (PFUser *friend in self.friends) {                          //2. Remove from the array of friends
            if ([friend.objectId isEqualToString:user.objectId]) {
                [self.friends removeObject:friend];
                break;
            }
        }
        [friendsRelation removeObject:user];                            //3. Remove from the backend
    }
    else {
        cell.accessoryType = UITableViewCellAccessoryCheckmark;
        [self.friends addObject:user];
        [friendsRelation addObject:user];
    }

    [self.currentUser saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
        if (error) {
            NSLog(@"Error %@ %@", error, [error userInfo]);
        }
    }];
}

before you had implemented didDeselectRow, which is not the right one

//this is the wrong method
- (void)tableView:(UITableView *)tableView didDeselectRowAtIndexPath:(NSIndexPath *)indexPath {
Robert Conti
Robert Conti
23,274 Points

Good catch. Appreciate your help!