self performSelector:@selector(loadData) withObject:nil - not working

Question

I use: self performSelector:@selector(loadData) withObject:nil... it look like working with some command only in "loadData" but the rest are not.

Here is my viewdidload:

- (void)viewDidLoad
{
    [super viewDidLoad];
    [mActivity startAnimating];
    [self performSelector:@selector(loadData) withObject:nil afterDelay:2];
    //[mActivity stopAnimating];
}

and here is loadData:

 -(void)loadData
{
    [mActivity startAnimating];
    NSLog(@"Start LoadData");
    AppDelegate *delegate=(AppDelegate *)[[UIApplication sharedApplication] delegate];
    NSString *selectData=[NSString stringWithFormat:@"select * from k_proverb ORDER BY RANDOM()"];
    qlite3_stmt *statement;
    if(sqlite3_prepare_v2(delegate.db,[selectData UTF8String], -1,&statement,nil)==SQLITE_OK){
        NSMutableArray *Alldes_str = [[NSMutableArray alloc] init];
        NSMutableArray *Alldes_strAnswer = [[NSMutableArray alloc] init];
        while(sqlite3_step(statement)==SQLITE_ROW)
        {
            NSString *des_strChk= [NSString stringWithUTF8String:(char *)sqlite3_column_text(statement,3)];
            if ([des_strChk isEqualToString:@"1"]){ 
                NSString *des_str= [NSString stringWithUTF8String:(char *)sqlite3_column_text(statement,4)];
                [Alldes_str addObject:des_str];
            }
        }
        Alldes_array = Alldes_str;
        Alldes_arrayAnswer = Alldes_strAnswer;
    }else{
        NSLog(@"ERROR '%s'",sqlite3_errmsg(delegate.db));
    }
    listOfItems = [[NSMutableArray alloc] init];
    NSDictionary *desc = [NSDictionary dictionaryWithObject:
                          Alldes_array forKey:@"description"];
    [listOfItems addObject:desc];
    //[mActivity stopAnimating];
    NSLog(@"Finish loaData");}

it give me only printing 2 line, but did not load my Data to the table, but if I copy all the code from inside "loadData" and past in "viewDidLoad", it load the data to the table.

Any advice or help please.

Answer 1

A few things: If you see any NSLog output at all, then the performSelector is succeeding. You should change the title of your question.

If you are trying to load data into a table, the method should end with telling the UITableView to reloadData (or a more elaborate load using begin/end updates).

If the listOfItems is the data supporting the table, get this working first by hard-coding something like this:

 -(void)loadData {

    listOfItems = [NSArray arrayWithObjects:@"test1", @"test2", nil];
    [self.tableView reloadData];
    return;

    // keep all of the code you wrote here.  it won't run until you remove the return
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {

    static NSString *CellIdentifier = @"Cell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (!cell) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
    }

    NSString *string = [listOfItems objectAtIndex:indexPath.row];
    cell.textLabel.text = string;
    return cell;

    // keep all of the code you probably wrote for this method here.
    // as above, get this simple thing running first, then move forward
}

Good luck!