TicTacToe/AAPLTicTacToeCheckboxView.m

/*
 
 Copyright (C) 2014 Apple Inc. All Rights Reserved.
 See LICENSE.txt for this sample’s licensing information
 
 Abstract:
 An example demonstrating adding accessibility to an NSView subclass that behaves like a checkbox by implementing the NSAccessibilityCheckBox protocol.
 
 */
 
#import "AAPLTicTacToeCheckboxView.h"
 
static NSString * const AAPLCheckboxSelected = @"CustomCheckboxSelected";
static NSString * const AAPLCheckboxUnselected = @"CustomCheckboxUnselected";
static const CGFloat AAPLCheckboxWidth = 12.0;
static const CGFloat AAPLCheckboxHeight = AAPLCheckboxWidth;
static const CGFloat AAPLCheckboxTextSpacing = 8.0; // spacing between box and text
 
@interface AAPLTicTacToeCheckboxView ()
 
@property (nonatomic, strong) NSString *checkboxText;
@property (nonatomic) BOOL checked;
 
@end
 
@implementation AAPLTicTacToeCheckboxView
 
- (instancetype)initWithFrame:(NSRect)frame
{
    self = [super initWithFrame:frame];
 
    if ( self != nil )
    {
        self.checkboxText = NSLocalizedString(@"AI opponent", "text of checkbox");
    }
 
    return self;
}
 
- (BOOL)acceptsFirstResponder
{
    return YES;
}
 
- (BOOL)becomeFirstResponder
{
    BOOL didBecomeFirstResponder = [super becomeFirstResponder];
    [self setNeedsDisplay:YES];
    return didBecomeFirstResponder;
}
 
- (BOOL)resignFirstResponder
{
    BOOL didResignFirstResponder = [super resignFirstResponder];
    [self setNeedsDisplay:YES];
    return didResignFirstResponder;
}
 
- (void)mouseUp:(NSEvent *)mouseEvent
{
    [self toggleCheckedState];
}
 
- (void)toggleCheckedState
{
    self.checked = !self.checked;
    [self.delegate checkboxCheckedStateChanged:self];
 
    // Whenever the value of the checkbox changes, let accessibility clients know
    NSAccessibilityPostNotification(self, NSAccessibilityValueChangedNotification);
 
    [self setNeedsDisplay:YES];
}
 
- (void)keyDown:(NSEvent *)keyEvent
{
    int spacebarKeyCode = 49;
 
    if ( [keyEvent keyCode] == spacebarKeyCode )
    {
        [self toggleCheckedState];
    }
    else
    {
        [super keyDown:keyEvent];
    }
}
 
- (void)drawRect:(NSRect)dirtyRect
{
    NSRect bounds = self.bounds;
    NSRect boxRect = NSMakeRect(bounds.origin.x,
                                bounds.origin.y + 5,
                                AAPLCheckboxWidth,
                                AAPLCheckboxHeight);
 
    NSRect textRect = NSMakeRect(bounds.origin.x + AAPLCheckboxWidth + AAPLCheckboxTextSpacing,
                                 bounds.origin.y,
                                 bounds.size.width,
                                 bounds.size.height);
 
    // Draw the checkbox box
    NSBundle *bundle = [NSBundle mainBundle];
    NSImage *boxImage = nil;
 
    if ( self.checked )
    {
        boxImage = [bundle imageForResource:AAPLCheckboxSelected];
    }
    else
    {
        boxImage = [bundle imageForResource:AAPLCheckboxUnselected];
    }
 
    [boxImage drawInRect:boxRect fromRect:NSZeroRect operation:NSCompositeSourceOver fraction:1.0];
 
    // Draw the checkbox text
    NSDictionary *textAttributes = @{ NSFontAttributeName : [NSFont fontWithName:@"Andale Mono" size:16.0f],
                                      NSForegroundColorAttributeName : [NSColor blackColor] };
    [self.checkboxText drawInRect:textRect withAttributes:textAttributes];
 
    // Draw the focus ring
    BOOL isFirstResponder = [[[NSApp mainWindow] firstResponder] isEqual:self];
    if ( isFirstResponder )
    {
        [NSGraphicsContext saveGraphicsState];
        NSSetFocusRingStyle(NSFocusRingOnly);
        [[NSBezierPath bezierPathWithRect:boxRect] fill];
        [NSGraphicsContext restoreGraphicsState];
    }
}
 
#pragma mark Accessibility
 
- (NSString *)accessibilityLabel
{
    return self.checkboxText;
}
 
- (NSNumber *)accessibilityValue
{
    return self.checked ? @YES : @NO;
}
 
- (BOOL)accessibilityPerformPress
{
    [self toggleCheckedState];
    return YES;
}
 
@end