运行自定义动画的首选方式 [英] Preferred way to run custom animations
问题描述
我需要在iOS应用中运行复杂的自定义动画.为此，我编写了一个需要重复调用的函数，并使用当前时间戳来计算屏幕上UIView元素的位置，颜色，阴影等.
I need to run a complex custom animation in an iOS app. For this, I wrote a function that needs to be called repeatedly and uses the current time-stamp to calculate positions, colors, shadows, etc. of UIView elements on the screen.
我似乎可以使用一大堆不同的方法来调用此函数:
There seem to be a whole bunch of different approaches I could use to have this function called:
- Multi-Threading
- Timers
- Dispatch Queues
- God knows what else... :)
我尝试先从一个单独的线程调用我的动画函数，但是当线程运行时，我看不到任何屏幕更新，除非我通过设备旋转手动触发刷新，所以我必须缺少一些步骤我从GUI线程内部调用更新函数，而不是我自己的视图或使View无效的东西.但是我什至不知道这是否是最好的方法.
I tried calling my animation-function from a separate thread first, but while the thread does run, I don't see any screen updates until I trigger a refresh manually with a device rotation, so I must be missing some step where I call the update functions from inside the GUI Thread instead of my own or invalidating the View or something... But I don't even know if this is the best approach...
在不阻塞GUI的情况下，尽可能快地(或以10ms左右的小延迟)保持调用函数(例如动画)的首选方法是什么，例如，更改背景颜色或视图位置，屏幕是否已更新?
What is the preferred way to keep calling a function (for an animation, for example) as quickly as possible (or with a small delay of 10ms or so) without blocking the GUI and in such a way that if this function, for example, changes the background color or position of a view, the screen gets updated?
如果可能的话，我想使用一种向后兼容的方法，因此最好不要使用iOS 8.1中引入的任何功能(夸张)...:)
If possible, I would like to use a method that is as backward-compatible as possible, so preferably something that doesn't use any features introduced in iOS 8.1 (exaggeration)... :)
旁边:
很抱歉，没有发布代码示例.我正在使用RoboVM，并且不想吓一跳"真正的XCode开发人员的任何答案.而且，这更多是一个一般性的概念性问题，而不是特定的错误修复.
推荐答案
我发现CADisplayLink的最佳性能.
displayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(displayLinkTick)];
[displayLink addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSRunLoopCommonModes];
- (void)displayLinkTick {
// Update your animation.
}
在销毁此视图时不要忘记拆卸，否则将调用displayLinkTick，直到应用程序退出:
Don't forget to teardown when you're destroying this view or else you'll have your displayLinkTick called until your application exits:
[displayLink removeFromRunLoop:[NSRunLoop currentRunLoop] forMode:NSRunLoopCommonModes];
或者，如果您正在使用(或转换为)CALayer，则子类将在动画键上从needsDisplayForKey:返回YES.然后，在CALayer子类的display方法中，应用self.presentationLayer对动画的更改.
Alternatively, if you're using (or convert to) CALayer, your subclass would return YES from needsDisplayForKey: on your animating key. Then, in your CALayer subclass' display method, you'd apply the changes that your self.presentationLayer has for your animation.
@property (assign) CGFloat myAnimatingProperty;
@implementation MyAnimatingLayer : CALayer
+ (BOOL)needsDisplayForKey:(NSString *)key {
if ([key isEqualToString:@"myAnimatingProperty"]) {
return YES;
}
return [super needsDisplayForKey:key];
}
- (void)display {
if ([self.animationKeys containsObject:@"myAnimatingProperty"]) {
CGFloat currentValue = self.presentationLayer.myAnimatingProperty;
// Update.
}
}
@end
第二种方法将使您真正轻松地链接到内置的缓动功能.
This second way will allow you to link in with the built-in easing functions really easily.
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