Ios 如何在设置动画时更改CALayer的颜色
我有一个圆弧,它绕着一个圆圈转,并且改变颜色三次。我在SO上使用了一个示例来开始: 这个例子是可行的,但是颜色是红色,然后是绿色,然后是蓝色。我希望它们是绿色,橙色,然后是红色。我试图弄清楚他是如何在代码中改变颜色的,这让我很困惑:Ios 如何在设置动画时更改CALayer的颜色,ios,objective-c,calayer,Ios,Objective C,Calayer,我有一个圆弧,它绕着一个圆圈转,并且改变颜色三次。我在SO上使用了一个示例来开始: 这个例子是可行的,但是颜色是红色,然后是绿色,然后是蓝色。我希望它们是绿色,橙色,然后是红色。我试图弄清楚他是如何在代码中改变颜色的,这让我很困惑: for (NSUInteger i = 0; i < 3; i++) { CAShapeLayer* strokePart = [[CAShapeLayer alloc] init]; strok
for (NSUInteger i = 0; i < 3; i++)
{
CAShapeLayer* strokePart = [[CAShapeLayer alloc] init];
strokePart.fillColor = [[UIColor clearColor] CGColor];
strokePart.frame = tutorialCircle.bounds;
strokePart.path = tutorialCircle.path;
strokePart.lineCap = tutorialCircle.lineCap;
strokePart.lineWidth = tutorialCircle.lineWidth;
// These could come from an array or whatever, this is just easy...
strokePart.strokeColor = [[UIColor colorWithHue: i * portion saturation:1 brightness:1 alpha:1] CGColor];
我的目标是把这些颜色变成绿橙红,而不是红绿蓝
谢谢
编辑:
这是部分的值:
const double portion = 1.0 / ((double)3);
啊,我刚想出来。以下是答案:
if (i == 0) {
strokePart.strokeColor = [UIColor greenColor].CGColor;
}
else if (i == 1) {
strokePart.strokeColor = [UIColor orangeColor].CGColor;
}
else if (i == 2) {
strokePart.strokeColor = [UIColor redColor].CGColor;
}
色调颜色系统以360度角定义颜色,其中0表示红色,108(360*0,3)表示绿色,108表示蓝色。这是如何生成颜色的:
strokePart.strokeColor = [[UIColor colorWithHue: 0 saturation:1 brightness:1 alpha:1] CGColor]; // RED
strokePart.strokeColor = [[UIColor colorWithHue: 0.3 saturation:1 brightness:1 alpha:1] CGColor]; // GREEN
strokePart.strokeColor = [[UIColor colorWithHue: 0.6 saturation:1 brightness:1 alpha:1] CGColor]; // BLUE
如果要更改为颜色,可以将部分移动其他值:
strokePart.strokeColor = [[UIColor colorWithHue: 0.3 + portion saturation:1 brightness:1 alpha:1] CGColor];
或者,您可以定义一个数组,其中包含您想要使用的颜色:
NSArray* colors = @[ UIColor.green, UIColor.orange, UIColor.red ];
for (id color in colors)
{
CAShapeLayer* strokePart = [[CAShapeLayer alloc] init];
strokePart.fillColor = [[UIColor clearColor] CGColor];
strokePart.frame = tutorialCircle.bounds;
strokePart.path = tutorialCircle.path;
strokePart.lineCap = tutorialCircle.lineCap;
strokePart.lineWidth = tutorialCircle.lineWidth;
// These could come from an array or whatever, this is just easy...
strokePart.strokeColor = [color CGColor];
部分的值是多少?它正好等于1/3,所以const double partition=1.0/((double)3);它相当于1/3或0.333333,对吗?是的,我的错,我刚刚得到了那份好工作!但是,如果您想要更多的代码改进,比如更少的条件和更灵活的方式,请查看我的答案。:)是的,这更干净。谢谢
NSArray* colors = @[ UIColor.green, UIColor.orange, UIColor.red ];
for (id color in colors)
{
CAShapeLayer* strokePart = [[CAShapeLayer alloc] init];
strokePart.fillColor = [[UIColor clearColor] CGColor];
strokePart.frame = tutorialCircle.bounds;
strokePart.path = tutorialCircle.path;
strokePart.lineCap = tutorialCircle.lineCap;
strokePart.lineWidth = tutorialCircle.lineWidth;
// These could come from an array or whatever, this is just easy...
strokePart.strokeColor = [color CGColor];