Question

I have a Navigation Controller embedded in a RootViewController. The elements present inside the RootViewController are a segmented control and a UIView. As the different segments are selected, the UIView displays a corresponding ViewController.

Now each of the ViewController being displayed in the UIView is a UITableViewController.

I need to display the table values as per the segment selections. And also if any of the row of the table is selected, it has to move to a newer ViewController with the detailed view.

I am able to display the UITableViewControllers as per the segment change. However, when i click on the row of the table, the newer ViewController that comes up is blank (Black Screen) even though I have created the particular ViewController in the Storyboard and set up an identifier as well.

Code for the Segmented Control change in ViewController.m

- (void)segmentedControlChangedValue:(UISegmentedControl*)segmentedControl {

int selIndex = segmentedControl.selectedIndex;

if (selIndex == 0)
{
    aTable = [[aTableViewController alloc] init];

    aTable.view.frame = self.myView.bounds;
    [self.myView addSubview:aTable.view];
    [self addChildViewController:aTable];
}

if (selIndex == 1)
{
    bTable = [[bTableViewController alloc] init];

    bTable.view.frame = self.myView.bounds;
    [self.myView addSubview:bTable.view];
    [self addChildViewController:bTable];

}

if (selIndex == 2)
{
    //NSLog (@"Well you selected a 3rd option");
}}

Code for the didSelectRowAtIndexPath:

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
[super tableView:tableView didSelectRowAtIndexPath:indexPath];

newDetailController* newController = [self.storyboard instantiateViewControllerWithIdentifier:@"Detail"];

newController = [[newDetailController alloc] init];

[[self navigationController] pushViewController:newController animated:YES];}

The pushViewController pushes an empty view for me even though I have specified the ViewController to use in the Storyboard design and also using an identifier.

Please help me in understanding what I must do to rectify this error.

UPDATE – The above problem has been resolved.

The problem I face now is being unable to access the data in the newViewController.

I pass the data to the newViewController as follows:

1. Create a class named newClass which contains all the elements I want to pass across.

2. Create a NSMutableArray “newObjects” in the firstViewController.

3. Create each newClass object at this method.
   

   • (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath object:(PFObject *)object
     {

   static NSString *CellIdentifier = @"Cell";

   customBigTableCell *cell = (customBigTableCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];

   if (cell == nil) {
   cell = [[customBigTableCell alloc] init];
   }

   cell.name.text = [object objectForKey:@"objName"];

   newClass* newObj = [[newClass alloc] init];

   newObj.objName = cell.name.text;

   [newObjects addObject:newObj];

   return cell;
}

   Pls pardon me .. for the indenting with the code block is messed up…
   Also the PFObject is cos i use Parse for database.

4. Add the created object to the newObjects array.

5. In the - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath method, this is the code

   • (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
     [super tableView:tableView didSelectRowAtIndexPath:indexPath];

     UIStoryboard* storyboard = [UIStoryboard storyboardWithName:@”MainStoryboard” bundle:[NSBundle mainBundle]];

     newDetailController* newController = [storyboard instantiateViewControllerWithIdentifier:@”UpcomingDetail”];

     obj = [[newClass alloc] init];

     NSIndexPath* path = [self.tableView indexPathForSelectedRow];

     obj = [newObjects objectAtIndex:path.row];

     NSLog(@”Row selected is %ld”, (long)path.row); //this returns the correct row selected

     NSLog(@”Movie selected is %@”, [[newObjects objectAtIndex:path.row] objName]);//however this is not the right one as per the cellForRowAtIndexPath method.

     [newController setNewObj:obj];

     [[self navigationController] pushViewController:newController animated:YES];
     }

When I run this code, the row is selected correctly. However I dont get the corresponding row in the database. The array gets stored with redundant data.

Answer 1

You need to get rid of that middle line:

newController = [[newDetailController alloc] init];

That just redefines newController (as an empty controller with no view set up), which you defined in the first line.