getting into the loop when doing progress view, ios - objective-c

Question

I am creating progress view by using CALayer by following
Header class
#import <UIKit/UIKit.h>
#import <QuartzCore/QuartzCore.h>
#interface ProgressBar : UIView
#property (strong, nonatomic) CALayer *subLayer;
#property (nonatomic) CGFloat progress;
#end
Implementation class
#implementation ProgressBar
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
self.progress = 0;
self.backgroundColor = [UIColor whiteColor];
self.subLayer = [CALayer layer];
self.subLayer.frame = self.bounds;
self.subLayer.backgroundColor = [UIColor orangeColor].CGColor;
[self.layer addSublayer:self.subLayer];
}
return self;
}
- (void)setProgress:(CGFloat)value {
NSLog(#"what is going on here");
if (self.progress != value) {
self.progress = value;
[self setNeedsLayout];
}
}
- (void)layoutSubviews {
CGRect rect = [self.subLayer frame];
rect.size.width = CGRectGetWidth([self bounds]) * self.progress;
[self.subLayer setFrame:rect];
}
In my viewcontroller, I am doing
#implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
self.pBar = [[ProgressBar alloc] initWithFrame:CGRectMake(0, 50, 320, 10)];
[self.view addSubview:self.pBar];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (IBAction)click:(id)sender {
[self.pBar setProgress:.8];
}
When (IBAction)click is fired, I am getting into the infinitive loop like the picture below
Does anyone know what I am getting into this loop. Please advice me on this issue. Thanks

Answer 1

The problem is that your setProgress: method calls the setProgress: method - recursion.
- (void)setProgress:(CGFloat)value {
NSLog(#"what is going on here");
if (self.progress != value) {
self.progress = value; // <-- This calls [self setProgress:value]
[self setNeedsLayout];
}
}
Change the bad line to:
_progress = value;
Setting the ivar directly is always required when you implement the setter method of a property.