Storeboard用segue切換viewController

一般是直接用storyboard把圖上的segue拉好，不用加程式碼。

但也可以如下列程式碼用performSegueWithIdentifier

-(void)buttonAction:(id)sender
{
    [self performSegueWithIdentifier:@"MySegueName" sender:sender];
}

//在執行上面的method之後，會先進來這個method，你可以在此把值pass進去

-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([[segue identifier] isEqualToString:@"MySegueName"]) 
    {
        NSIndexPath *indexPath = [self.tableView indexPathForSelectedRow];
        NSDate *object = _objects[indexPath.row];
        [[segue destinationViewController] setDetailItem:object];
    }
}