objective-c - CALayer 子类中的颜色属性

Question

这让我发疯。我正在尝试更改 CALayer 子类的自定义属性“mycolor”，这是我的代码:

#import "Circle"

@interface Circle()
   @property (nonatomic, strong) UIColor * mycolor;
   @property (nonatomic) float initial_angle;
   @property (nonatomic) float end_angle;
@end

@implementation Circle

@synthesize mycolor;
@synthesize initial_angle, end_angle;

- (id) init {
    self = [super init];
    if (self) {

        CGFloat red =  (CGFloat)random()/(CGFloat)RAND_MAX;
        CGFloat blue = (CGFloat)random()/(CGFloat)RAND_MAX;
        CGFloat green = (CGFloat)random()/(CGFloat)RAND_MAX;
        self.mycolor = [UIColor colorWithRed:red green:green blue:blue alpha:1.0];
        self.backgroundColor =  [UIColor clearColor].CGColor;

    }
    return self;
}


-(void) changeColor {
    CGFloat red =  (CGFloat)random()/(CGFloat)RAND_MAX;
    CGFloat blue = (CGFloat)random()/(CGFloat)RAND_MAX;
    CGFloat green = (CGFloat)random()/(CGFloat)RAND_MAX;
    self.mycolor = [UIColor colorWithRed:red green:green blue:blue alpha:1.0];
}

- (void) animate {
    float final = arc4random() % 360;
    float afrom = self.initial_angle;
    self.initial_angle = final;
    CABasicAnimation * anim = [CABasicAnimation animationWithKeyPath:@"initial_angle"];
    anim.fromValue = [NSNumber numberWithFloat:afrom];
    anim.toValue = [NSNumber numberWithFloat:final];
    anim.duration = 5;
    anim.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
    [self addAnimation:anim forKey:@"initial_angle"];

    final = arc4random() % 360;
    afrom = self.end_angle;
    self.end_angle = final;
    anim = [CABasicAnimation animationWithKeyPath:@"end_angle"];
    anim.fromValue = [NSNumber numberWithFloat:afrom];
    anim.toValue = [NSNumber numberWithFloat:final];
    anim.duration = 5;
    anim.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
    [self addAnimation:anim forKey:@"end_angle"];    

}

- (void) drawInContext:(CGContextRef)ctx {

    CGContextMoveToPoint(ctx, 50, 50);
    CGContextAddArc(ctx, 50, 50, 50, initial_angle*M_PI/180, end_angle*M_PI/180, 0);
    CGContextClosePath(ctx);
    NSLog(@"%@", self.mycolor);

    CGContextSetFillColorWithColor(ctx, self.mycolor.CGColor);   
    CGContextFillPath(ctx);

}

+ (BOOL)needsDisplayForKey:(NSString*)key {
    if ([key isEqualToString:@"initial_angle"]||
        [key isEqualToString:@"end_angle"]||
        [key isEqualToString:@"mycolor"]) {
        return YES;
    } else {
        return [super needsDisplayForKey:key];
    }
}

@end

changeColor 和 animate 是公共(public)方法。每秒都会调用 Animate，并在每次用户点击圆时更改颜色。

一切正常，除了在“drawInContext”中 mycolor 始终为空。不知道为什么。

Answer 1

您是否尝试过在设置 mycolor 后立即记录它的值？

你的代码看起来不错，所以肯定发生了一些奇怪的事情。您是否有可能在某处为 mycolor 创建了自定义 setter 或 getter 方法，但没有正确实现它？

我假设您正在使用 ARC - 您是否尝试过直接设置 mycolor ivar 而不是通过 setter ？ (在 ARC 中应该没问题 - 它不会泄漏或意外释放)