Refactoring after changing local variable into instance variable - objective-c

Question

Am having some trouble with my code after changing a local variable into an instance variable. To be specific, I have been having trouble with my code in my HypnosisterAppDelegate.m file after changing one line of code from:
HypnosisView *view = [[HypnosisView alloc]initWithFrame:screenRect];
to
view = [[HypnosisView alloc]initWithFrame:screenRect];
I have commented out the error messages in HypnosisterAppDelegate.m Can you tell me what's wrong? Thanks in advance.
HypnosisterAppDelegate.m
#import "HypnosisterAppDelegate.h"
#import "HypnosisView.h"
#implementation HypnosisterAppDelegate
#synthesize window = _window;
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
// Override point for customization after application launch.
CGRect screenRect = [[self window]bounds];
// Create the UIScrollView to have the size of a window, matching its size
view = [[HypnosisView alloc]initWithFrame:screenRect];
[scrollView setMinimumZoomScale:1.0]; // Unknown receiver "scrollView"; should it be "UIScrollView"?
[scrollView setMaximumZoomScale:5.0]; // Unknown receiver "scrollView"; should it be "UIScrollView"?
//You will get a warning here, ignore it for now
[scrollView setDelegate:self]; // Unknown receiver "scrollView"; should it be "UIScrollView"?
[[self window] addSubview:scrollView]; // Unknown receiver "scrollView"; should it be "UIScrollView"?
//Create the HypnosisView with a frame that is twice the size of the screen
CGRect bigRect = screenRect;
HypnosisView *view = [[HypnosisView alloc]initWithFrame:screenRect];
// Add the HypnosisView as a subview of the scrollView instead of the window
[scrollView addSubview:view]; // Unknown receiver "scrollView"; should it be "UIScrollView"?
// Tell the scrollView how big its virtual world is
[scrollView
setContentSize:bigRect.size]; // Unknown receiver "scrollView"; should it be "UIScrollView"?
BOOL success = [view becomeFirstResponder];
if (success) {
NSLog(#"HypnosisView became the first responder");
} else {
NSLog(#"Could not become the first responder");
}
self.window.backgroundColor = [UIColor whiteColor];
[self.window makeKeyAndVisible];
return YES;
}
-(UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
return view;
}
#end
HypnosisView.h
#import <Foundation/Foundation.h>
#interface HypnosisView : UIView {
}
#property(nonatomic,strong)UIColor *circleColor;
#end

Answer 1

You don't have a variable called scrollView anywhere. I'd guess (especially from the comment // Create the UIScrollView to have the size of a window, matching its size, and also having gone through this book myself) that you meant to create a UIScrollView:
// not: view = [[HypnosisView alloc]initWithFrame:screenRect];
// but:
UIScrollView * scrollView = [[UIScrollView alloc] initWithFrame:screenRect];
and then add your HypnosisView later as a subview.