Beginner iPhone Controller Question

I have a view that only has a button UIButton. First time clicking the butto开发者_运维知识库n will draw a square above the button and the second time will replace the square with a circle.

I need some help on writing the controller code. Please guide me to the right path. Thanks

design a shape class. Add your shapes as UIImageViews. with each button click, change the alpha on click.

@interface Shape: UIView {
  UIImageView *square;
  UIimageView *circle;
  BOOL isSquare;
}

@property (nonatomic, retain) UIImageView *square;
@property (nonatomic, retain) UIImageView *circle;
@property BOOL isSquare;

-(void)changeShape;
@end

@implementation Shape
@synthesize square;
@synthesize circle;
@synthesize isSquare;

- (id)initWithFrame:(CGRect)frame {

if ((self = [super initWithFrame:frame])) {

    self.frame = //frame size.


    //assume a square image exists.
    square = [[UIImageView alloc] initWithImage: [UIImage imageNamed: @"square.png"]];
    square.alpha = 1.0;
    [self addSubview: square];

    //assume a circle image exists.
    circle = [[UIImageView alloc] initWithImage: [UIImage imageNamed: @"circle.png"]];
    circle.alpha = 0.0;
    [self addSubview: circle];

    isSquare = YES;

    }
    return self;
}

-(void)changeShape {

if (isSquare == YES) { 
    square.alpha = 0.0;
    cirle.alpha = 1.0;
    isSquare = NO;
 }

if (isSquare == NO) {
    circle.alpha = 0.0;
    square.alpha = 1.0;
    isSquare = YES;
}


}

//rls memory as necessary.
@end

////////////////////////////////in your view controller class.

instantiate your class and add it as a subview.

@class Shape;

@interface ShapeViewController : UIViewController {
    Shape *shape;
}

@property (nonatomic, retain) Shape *shape;


-(IBAction)clickedButton:(id)sender;

@end

////////

#import "Shape.h"
@implementation ShapeViewController;

 //add your shape as a subview in viewDidLoad:

-(IBAction)clickedButton:(id)sender {
  [shape changeShape];
}
@end

That should give you a good basic implementation idea. Essentially, you design a class and then change its shape with each click. It should alternate from square/circle/square/circle. Hope that helps.