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copied!<p>Here's a working demo</p> <h2>AppDelegate</h2> <pre><code>inline static CGPoint CGRectGetCenter( CGRect r ) { return (CGPoint){ CGRectGetMidX( r ), CGRectGetMidY( r ) } ; } @implementation AppDelegate - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; // Override point for customization after application launch. self.window.backgroundColor = [UIColor whiteColor]; [self.window makeKeyAndVisible]; CGFloat size = 300.0 ; for( int index =0; index < 10; ++index ) { RingView * view = [[ RingView alloc ] initWithFrame:(CGRect){ .size = { size, size } } ] ; view.outerRadius = size * 0.5 ; view.innerRadius = view.outerRadius - 20.0 ; view.center = CGRectGetCenter( self.window.bounds ) ; [ self.window addSubview:view ] ; size -= 20.0 ; } return YES; } -(void)ringViewTapped:(RingView*)sender sliceIndex:(NSNumber*)sliceIndex { [ UIView animateWithDuration:0.25 animations:^{ sender.transform = CGAffineTransformMakeRotation( -[ sliceIndex doubleValue ] * M_PI_2 ) ; } ] ; } @end </code></pre> <h2>RingView</h2> <pre><code>@interface RingView : UIControl @property ( nonatomic ) CGFloat innerRadius, outerRadius ; @end @implementation UIResponder (Send) -(BOOL)sendMessage:(SEL)message withObject:(id)obj0 withObject:(id)obj1 { UIResponder * target = self ; do { if ( [ target respondsToSelector:message ] ) { [ target performSelector:message withObject:obj0 withObject:obj1 ] ; return YES ; } target = [ target nextResponder ] ; } while( target ) ; return NO ; } @end @implementation UIColor (RandomColor) +(UIColor*)randomColor { return [ UIColor colorWithHue:((CGFloat)arc4random_uniform( 6 ) / 6.0) saturation:1.0 brightness:1.0 alpha:1.0 ] ; } @end static CGPathRef CGPathCreateWedge( CGFloat innerRadius, CGFloat outerRadius ) { CGMutablePathRef p = CGPathCreateMutable() ; CGPathMoveToPoint( p, NULL, 0, innerRadius ) ; CGPathAddLineToPoint( p, NULL, 0, outerRadius ) ; CGPathAddArcToPoint( p, NULL, outerRadius, outerRadius, outerRadius, 0.0, outerRadius ) ; CGPathAddLineToPoint( p, NULL, innerRadius, 0.0 ) ; CGPathAddArcToPoint( p, NULL, innerRadius, innerRadius, 0.0, innerRadius, innerRadius ) ; CGPathCloseSubpath( p ) ; return p ; } @interface RingView () @end @implementation RingView -(void)_ensureSlices { if ( self.layer.sublayers.count == 0 ) { CGPathRef p = CGPathCreateWedge( self.innerRadius, self.outerRadius ) ; for( int index=0; index < 4; ++index ) { CAShapeLayer * layer = [ CAShapeLayer layer ] ; layer.path = p ; { CGColorRef c = [ [ UIColor randomColor ] CGColor ] ; layer.fillColor = c ; CGColorRelease( c ) ; } layer.transform = CATransform3DMakeRotation( (CGFloat)index * M_PI_2 - M_PI_4, 0.0, 0.0, 1.0 ) ; [ self.layer addSublayer:layer ] ; } CGPathRelease( p ) ; } } -(id)initWithFrame:(CGRect)frame { self = [ super initWithFrame:frame ] ; [ self addTarget:nil action:@selector( tapped:event: ) forControlEvents:UIControlEventTouchUpInside ] ; return self ; } -(void)layoutSubviews { [ self _ensureSlices ] ; CGRect bounds = self.bounds ; self.bounds = (CGRect){ { -0.5f * bounds.size.width, -0.5f * bounds.size.height }, bounds.size } ; } -(UIView *)hitTest:(CGPoint)p withEvent:(UIEvent *)e { UIView * result = [ super hitTest:p withEvent:e ] ; if ( result == self ) { CGFloat r = sqrt( p.x * p.x + p.y * p.y ) ; if ( r < self.innerRadius || r > self.outerRadius ) { return nil ; } } return result ; } -(IBAction)tapped:(id)sender event:(UIEvent*)event { CGPoint p = [ [ [ event touchesForView:self ] anyObject ] locationInView:self ] ; int index = 0 ; for( CAShapeLayer * layer in self.layer.sublayers ) { CGPoint testPoint = [ layer convertPoint:p fromLayer:self.layer ] ; if ( CGPathContainsPoint( layer.path, NULL, testPoint, false ) ) { [ self sendMessage:@selector( ringViewTapped:sliceIndex: ) withObject:self withObject:@( index ) ] ; } ++index ; } } -(void)setOuterRadius:(CGFloat)r { _outerRadius = r ; [[self.layer.sublayers copy ] makeObjectsPerformSelector:@selector( removeFromSuperlayer ) ] ; [ self setNeedsLayout ]; } -(void)setInnerRadius:(CGFloat)r { _innerRadius = r ; [[self.layer.sublayers copy ] makeObjectsPerformSelector:@selector( removeFromSuperlayer ) ] ; [ self setNeedsLayout ]; } @end </code></pre>

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