Question

I have taken a imageview in applicationDidFinishLaunching as shown below.

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
 {
      self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
      UIImageView* imageBg = [[UIImageView alloc]initWithFrame:CGRectMake(0, 20, 320, 460)];
      imageBg.image = [UIImage imageNamed:@"AppBG.png"];
       [self.window addSubview:imageBg];
       [self.window sendSubviewToBack:imageBg]; 
 }

Now In rootViewController I have one button

My need is that on press of button in RootViewController I want to change the image from AppBG.png to AppBG1.png

Answer 1

Make your UIImageView, imageBg an property, synthesize it.

Then Use following code on button click:

MyAppdelegate *appdelegate = (MyAppdelegate *)[[UIApplication sharedApplication] delegate];
appdelegate.imageBg.image = [UIImage imageNamed:@"AppBG1.png"];