Question

how can i update GUI elements with values from a queue?
if i use async queue construct, textlable don’t get updated.
Here is a code example i use:

- (IBAction)dbSizeButton:(id)sender {
    dispatch_queue_t getDbSize = dispatch_queue_create("getDbSize", NULL);
    dispatch_async(getDbSize, ^(void)
    {
        [_dbsizeLable setText:[dbmanager getDbSize]]; 
    });

   dispatch_release(getDbSize);
}

Thank you.

Answer 1

As @MarkGranoff said, all UI needs to be handled on the main thread. You could do it with performSelectorOnMainThread, but with GCD it would be something like this:

- (IBAction)dbSizeButton:(id)sender {

    dispatch_queue_t getDbSize = dispatch_queue_create("getDbSize", NULL);
    dispatch_queue_t main = dispatch_get_main_queue();
    dispatch_async(getDbSize, ^(void)
    {
        dispatch_async(main, ^{ 
            [_dbsizeLable setText:[dbmanager getDbSize]];
        });
    });

    // release
}