0
我有一个图层,并在其drawInContext:
我画一个属性的字符串与drawInRect:
。这是我如何初始化图层。动画NSMutableAttributedString颜色 - 字符串消失
+ (id)layer
{
Character *layer = [[self alloc] init];
if (layer) {
NSDictionary *attributes = @{NSFontAttributeName: [UIFont fontWithName:@"Fabada" size:72]};
layer.symbol = [[NSMutableAttributedString alloc] initWithString:@"X" attributes:attributes];
}
return layer;
}
我想动画字符串的颜色,所以我有三个动力学属性。
@interface Character : CALayer
@property (nonatomic, strong) NSMutableAttributedString *symbol;
@property (nonatomic) int red;
@property (nonatomic) int green;
@property (nonatomic) int blue;
@end
@implementation Character
@dynamic red;
@dynamic green;
@dynamic blue;
/* ... */
在绘制方法中,我设置了前景色。
/* Set symbol color */
NSRange range = {0, [self.symbol length]};
UIColor *foreground = [UIColor colorWithRed:self.red /255.0
green:self.green/255.0
blue:self.blue /255.0
alpha:1];
[self.symbol addAttribute:NSForegroundColorAttributeName value:foreground range:range];
CGRect symbolRect; /* The frame */
[self.symbol drawInRect:symbolRect];
该字符根据需要出现在屏幕上。但是,一旦我将一个CABasicAnimation
添加到图层,该符号就会消失。
CABasicAnimation *animation = [CABasicAnimation animation];
animation.duration = 10.0;
animation.fillMode = kCAFillModeForwards;
animation.removedOnCompletion = NO;
animation.delegate = self;
animation.fromValue = [NSNumber numberWithInt:0];
animation.toValue = [NSNumber numberWithInt:255];
[self.character addAnimation:animation forKey:@"blue"];
这个症状暗示了什么?我如何动画NSAttributedString
属性?