- (AppDataObject*) theAppDataObject
{
    id<AppDelegateProtocol> theDelegate = (id<AppDelegateProtocol>) [UIApplication sharedApplication].delegate;
    AppDataObject* theDataObject;
    theDataObject = (AppDataObject*) theDelegate.theAppDataObject;
    return theDataObject;
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    tempImageString = (((championList *) [self.champions objectAtIndex:indexPath.row]).championImage);

    AppDataObject *theDataObject = [self theAppDataObject];
    NSLog(@"tempIm-g = %@",tempImageString);
    theDataObject.imageString = tempImageString;
    NSLog(@"theAppDataObject.imageString = %@",theDataObject.imageString);

    [self.navigationController popToRootViewControllerAnimated:YES];
}

-(void)viewWillAppear:(BOOL)animated
{
    AppDataObject* theDataObject = [self theAppDataObject];
    UIImage *tempImage = [UIImage imageNamed:theDataObject.imageString];
    NSLog(@"temp image = %@",tempImage);
    [choosenChampionImageView setImage:tempImage];
}

AppDelegate *appdelegate = (AppDelegate *)[[UIApplication sharedApplication]delegate];
appdelegate.imageString = tempImageString;

@interface championsListTableViewController : UITableViewController
{
    NSString *tempImageString;

    AppDataObject* theDataObject;
}

@property(strong,nonatomic) NSString *tempImageString;

@property(strong,nonatomic) AppDataObject* theDataObject;

theAppDataObject.imageString = [tempImageString retain];

// this the way too declare  a protocal.
  // .h file
 @protocol TestProtocol <NSObject>

 -(void)testMyProtocolMethod:(NSString *)testvalue;

 @end

@interface TestProtocolClass: NSObject
{
   id <TestProtocol> delegate;

}
 @property (nonatomic , assign) id <TestProtocol> delegate;
 /* synthesize in the .m file   of          this      class*/
 @end



 //Now you have to use this protocol in any class where you want to use , Do like as:
 //let us suppose you want to use this protocal method in a class named "DemoProtocal".
 // .h file
 import "TestProtocol.h"
 @interface DemoProtocal <TestProtocol>{

 }
 @end

//.m file
 #import "DemoProtocal.h"
 @implementation DemoProtocal

- (id)init{

  TestProtocol *test = [[TestProtocol alloc]init];
  test.delegate = self;

 }

-(void)testMyProtocolMethod:(NSString *)testvalue{

  // Do appropriate things.
 }
 @end

//Declare a variable from where you want to set the value of the "AppDelegate Class".
 //in the yourclass.h file.
 AppDelegate/* this is the main class of the Application*/ *appDel;

//and initialize it where you want to use or you can initialize at the init of the class.

appDel = (AppDelegate *)[[UIApplication sharedApplication]delegate];

 // Then set the value.
 appDel.imageString = tempImageString;