ios - 使用 Core Animation 改变 cornerRadius

Question

我正在尝试通过以下方式更改按钮 (OpenNoteVisible.layer) 的角半径:

CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"cornerRadius"];
animation.timingFunction = [CAMediaTimingFunction     functionWithName:kCAMediaTimingFunctionLinear];
animation.fromValue = [NSNumber numberWithFloat:10.0f];
animation.toValue = [NSNumber numberWithFloat:0.0f];
animation.duration = 1.0;
[animation.layer setCornerRadius:140.0];
[OpenNoteVisible.layer addAnimation:animation forKey:@"cornerRadius"];

但是这段代码在行 [animation.layer setCornerRadius:140.0] 处给出了一个错误； 我不明白为什么。我已经导入了 Quartz 核心框架。

Answer 1

您正在动画对象的图层属性上设置圆角半径；此动画对象没有图层属性。

您需要在要设置动画的对象的图层上设置圆角半径，在本例中为 OpenNoteVisible。您还需要确保动画对象的 toValue 与您在图层上设置的值匹配，否则您会得到奇怪的动画。

您的代码现在应该是:

CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"cornerRadius"];
animation.timingFunction = [CAMediaTimingFunction     functionWithName:kCAMediaTimingFunctionLinear];
animation.fromValue = [NSNumber numberWithFloat:10.0f];
animation.toValue = [NSNumber numberWithFloat:140.0f];
animation.duration = 1.0;
[OpenNoteVisible.layer setCornerRadius:140.0];
[OpenNoteVisible.layer addAnimation:animation forKey:@"cornerRadius"];