MMDrawerController and instantiating many view controllers - ios

Question

This is a specific MMDrawerController question, although probably relates to other iOS drawer controllers out there.
I've got my MMDrawerController working nicely, and can load different view controllers into the 'center' by selecting a row in my drawer tableview.
However, I want to avoid instantiating my view controllers every time I select a menu item in my drawer. It seems inefficient, especially if the user will switch between screens many times during a session. I'm guessing a better way is to store the (instantiated) view controllers I'm using as a variable and to reuse? I have quite a few view controllers to potentially load into the center, each of which will do some 'work' initially in viewDidLoad.
Here is how I am loading a new view controller into the center (in my DrawerViewController.didSelectRowAtIndexPath method):
MyViewConroller * newCenter = [[MyViewConroller alloc] init];
UINavigationController * nav = [[MMNavigationController alloc] initWithRootViewController:newCenter];
if(indexPath.row==0){
[self.mm_drawerController
setCenterViewController:nav
withCloseAnimation:YES
completion:nil];
}
Thoughts/comments about the best approach of loading these view controllers would be appreciated.

Answer 1

This method is working well for me and there is no need to instantiate a new view controller or navigation controller every time the user changes views.
Declare a mutable array to hold your navigation controllers:
#property (nonatomic, strong) NSMutableArray *navigationControllerArray;
Initialise and fill the array with the same number of empty strings as you have view controllers:
- (void)viewDidLoad
{
[super viewDidLoad];
self.navigationControllerArray = [[NSMutableArray alloc] initWithObjects:#"",#"",#"",nil];
}
In your UITableViewDelegate, check to see if the object at the selected row is a UINavigationController. If it is not, instantiate a new navigation controller and replace the empty string in your navigation controller array with it.
Set this navigation controller as the center view controller:
#pragma mark - UITableViewDelegate
-(NSIndexPath *)tableView:(UITableView *)tableView willSelectRowAtIndexPath:(NSIndexPath *)indexPath {
NSObject *navigationController = [self.viewControllerArray objectAtIndex:indexPath.row];
if (![navigationController isKindOfClass:[UINavigationController class]]) {
UIViewController *newViewController;
switch (indexPath.row) {
case 0:
newViewController = (UIViewController *)[[AccountListTableViewController alloc] init];
break;
case 1:
newViewController = (UIViewController *)[[PageDetailViewController alloc] init];
break;
case 2:
newViewController = (UIViewController *)[[LoginViewController alloc] init];
break;
default:
newViewController = (UIViewController *)[[AccountListTableViewController alloc] init];
break;
}
navigationController = (UINavigationController *)[[UINavigationController alloc] initWithRootViewController:(UIViewController *)newViewController];
[self.viewControllerArray replaceObjectAtIndex:indexPath.row withObject:navigationController];
}
[self.mm_drawerController setCenterViewController:(UINavigationController *)navigationController withCloseAnimation:YES completion:nil];
return indexPath;
}