Prevent iOS from taking screen capture of app before going into background

Solution 1:

You are on the right track. This is Apple's recommended way to do this as noted in the iOS Application Programming Guide:

Remove sensitive information from views before moving to the background. When an application transitions to the background, the system takes a snapshot of the application’s main window, which it then presents briefly when transitioning your application back to the foreground. Before returning from your applicationDidEnterBackground: method, you should hide or obscure passwords and other sensitive personal information that might be captured as part of the snapshot.

Solution 2:

Need to write the code in Application life cycle methods, here we are putting an imageView while the app animate to background :

-(void)applicationWillResignActive:(UIApplication *)application
{
    imageView = [[UIImageView alloc]initWithFrame:[self.window frame]];
    [imageView setImage:[UIImage imageNamed:@"Splash_Screen.png"]];
    [self.window addSubview:imageView];
}

Here is the code to remove the imageView:

- (void)applicationDidBecomeActive:(UIApplication *)application
{
    if(imageView != nil) {
        [imageView removeFromSuperview];
        imageView = nil;
    }
}

It is working and properly tested.