Question

这让我疯了。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是公共方法。每当用户点击圈数时，Animate每秒调用一次并更改颜色。

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

Answer 1

您是否尝试在设置后立即记录mycolor的值？

你的代码看起来很合理，所以肯定会发生一些奇怪的事情。您是否有可能在某处为mycolor创建了自定义setter或getter方法而未正确实现？

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）

Answer 2

@synthesize mycolor = _mycolor;
_mycolor = [UIColor colorWithRed:red green:green blue:blue alpha:1.0];

尝试在init方法和drawInContext中使用_mycolor。

    CGContextSetFillColorWithColor(ctx, self.mycolor.CGColor);

我认为在drawInContext中你可以使用实例变量而不是属性。

Answer 3

CALayer的正确初始化程序为+layer，您应该覆盖+layer方法，而不是甚至根本不会被调用的-init。

CALayer子类中的Color属性

3 个答案: