TapView.m

/*
     File: TapView.m
 Abstract: UIView subclass that can highlight itself when locally or remotely tapped.
  Version: 2.1
 
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 */
 
#import "TapView.h"
 
@import QuartzCore;
 
static const CGFloat kActivationInset = 10.0f;
 
@interface TapView ()
 
@property (nonatomic, assign, readwrite) BOOL   localTouch;
 
@end
 
@implementation TapView
 
- (id)initWithCoder:(NSCoder *)aDecoder
{
    self = [super initWithCoder:aDecoder];
    if (self != nil) {
        [self commonInit];
    }
    return self;
}
 
- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self != nil) {
        [self commonInit];
    }
    return self;
}
 
- (void)commonInit
{
    assert( ! self.isMultipleTouchEnabled );
    self.layer.borderColor = [[UIColor darkGrayColor] CGColor];
    // Observe ourself to learn about someone changing the remoteTouch property.
    [self addObserver:self forKeyPath:@"remoteTouch" options:0 context:&self->_remoteTouch];
}
 
- (void)dealloc
{
    [self removeObserver:self forKeyPath:@"remoteTouch" context:&self->_remoteTouch];
}
 
- (void)updateLayerBorder
{
    self.layer.borderWidth = (self.localTouch || self.remoteTouch) ? kActivationInset : 0.0f;
}
 
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
    if (context == &self->_remoteTouch) {
        // If the remoteTouch property changes, redraw.
        [self updateLayerBorder];
    } else {
        [super observeValueForKeyPath:keyPath ofObject:object change:change context:context];
    }
}
 
- (void)resetTouches
    // See comment in header.
{
    [self localTouchUpNotify:NO];
    if (self.remoteTouch) {
        self.remoteTouch = NO;
    }
}
 
#pragma mark - Touch tracking
 
- (void)localTouchDown
{
    if ( ! self.localTouch ) {
        id <TapViewDelegate>  strongDelegate;
 
        self.localTouch = YES;
        [self updateLayerBorder];
 
        strongDelegate = self.delegate;
        if ([strongDelegate respondsToSelector:@selector(tapViewLocalTouchDown:)]) {
            [strongDelegate tapViewLocalTouchDown:self];
        }
    }
}
 
- (void)localTouchUpNotify:(BOOL)notify
{
    if ( self.localTouch ) {
        self.localTouch = NO;
        [self updateLayerBorder];
        if (notify) {
            id <TapViewDelegate>  strongDelegate;
 
            strongDelegate = self.delegate;
            if ([strongDelegate respondsToSelector:@selector(tapViewLocalTouchUp:)]) {
                [strongDelegate tapViewLocalTouchUp:self];
            }
        }
    }
}
 
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    #pragma unused(touches)
    #pragma unused(event)
    [self localTouchDown];
}
 
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    #pragma unused(touches)
    #pragma unused(event)
    [self localTouchUpNotify:YES];
}
 
- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event
{
    #pragma unused(touches)
    #pragma unused(event)
    [self localTouchUpNotify:YES];
}
 
@end