Make them properties.
In your interface have:
@property (strong, nonatomic) UIView *myView;
@property (strong, nonatomic) UILabel *myLabel;
@property (strong, nonatomic) UIButton *myButton;
In your delegate method:
CGRect frame= CGRectMake(0, 0, 320, 428);
self.myView=[[UIView alloc] initWithFrame:frame];
self.myView.backgroundColor=[UIColor greenColor];
self.myView.alpha=0.7;
CGRect labelFrame = CGRectMake( 0, 0, 500, 30 );
self.myLabel = [[UILabel alloc] initWithFrame: labelFrame];
self.myLabel.textColor = [UIColor orangeColor];
self.myLabel.text = [NSString stringWithFormat:@"%@%@", @"Title: ", symbol.data];
self.myButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
self.myButton.frame = CGRectMake(10, 50, 100, 50);
self.myButton.tag = 121;
[self.myButton setTitle:@"Do Something" forState:UIControlStateNormal];
[self.myButton setBackgroundImage:nil forState:UIControlStateNormal];
[self.myButton addTarget:self action:@selector(testAction:) forControlEvents:UIControlEventTouchUpInside];
[self.myView addSubview:self.myLabel];
[self.myView addSubview:self.myButton];
reader.cameraOverlayView = self.myView;
Finally in your action:
- (void)testAction: (id)sender
{
// self.myView, self.myLabel and self.myButton are all available.
}