Iphone iOS核心动画:CALayer bringSublayerToFront?
如何将Iphone iOS核心动画:CALayer bringSublayerToFront?,iphone,objective-c,ios,core-animation,calayer,Iphone,Objective C,Ios,Core Animation,Calayer,如何将CALayer子层带到所有子层的前面,类似于-[UIView bringSubviewToFront]?我认为不存在这样的方法,但很容易自己滚动 // CALayer+Additions.h @interface CALayer (Additions) - (void)bringSublayerToFront:(CALayer *)layer; - (void)sendSublayerToBack:(CALayer *)layer; @end // CALayer+Additions.
CALayer子层
带到所有子层的前面,类似于-[UIView bringSubviewToFront]
?我认为不存在这样的方法,但很容易自己滚动
// CALayer+Additions.h
@interface CALayer (Additions)
- (void)bringSublayerToFront:(CALayer *)layer;
- (void)sendSublayerToBack:(CALayer *)layer;
@end
// CALayer+Additions.m
@implementation CALayer (Additions)
- (void)bringSublayerToFront:(CALayer *)layer {
CALayer *superlayer = self.superlayer;
[self removeFromSuperlayer];
[superlayer insertSublayer:gradientLayer atIndex:[self.sublayers count]-1];
}
- (void)sendSublayerToBack:(CALayer *)layer {
CALayer *superlayer = self.superlayer;
[self removeFromSuperlayer];
[superlayer insertSublayer:gradientLayer atIndex:0];
}
这是@MattDiPasquale实现的变体,更准确地反映了UIView的逻辑:
- (void) bringSublayerToFront:(CALayer *)layer
{
[layer removeFromSuperlayer];
[self insertSublayer:layer atIndex:[self.sublayers count]];
}
- (void) sendSublayerToBack:(CALayer *)layer
{
[layer removeFromSuperlayer];
[self insertSublayer:layer atIndex:0];
}
注意:如果您不使用ARC,您可能希望在两个函数的顶部添加[层保留]
,在底部添加[层释放]
,以确保层
在保留计数=1的情况下不会意外破坏。此处是正确的代码
- (void)bringSublayerToFront:(CALayer *)layer {
CALayer *superlayer = layer.superlayer;
[layer removeFromSuperlayer];
[superlayer insertSublayer:layer atIndex:[superlayer.sublayers count]];
}
- (void)sendSublayerToBack:(CALayer *)layer {
CALayer *superlayer = layer.superlayer;
[layer removeFromSuperlayer];
[superlayer insertSublayer:layer atIndex:0];
}
这是正确的代码:
-(void)bringSubLayerToFront:(CALayer*)layer
{
[layer.superLayer addSubLayer:layer];
}
-(void)sendSubLayerToBack:(CALayer*)layer
{
[layer.superlayer insertSublayer:layer atIndex:0];
}
我很好奇为什么这些答案都没有提到CALayer上的zPosition属性。核心动画查看此属性以确定层渲染顺序。值越高,它越靠近前面。只要zPosition为0,这些答案都有效,但要轻松地将层置于最前面,请将其zPosition值设置为高于所有其他子层。您可以在CALayer上的类别中实现此功能,如下所示: CALayer+Extension.h
#import <QuartzCore/QuartzCore.h>
typedef void (^ActionsBlock)(void);
@interface CALayer (Extension)
+ (void)performWithoutAnimation:(ActionsBlock)actionsWithoutAnimation;
- (void)bringSublayerToFront:(CALayer *)layer;
@end
为了便于访问,您可以在项目的Prefix.pch(预编译头)文件中导入“CALayer+Extension.h”。创建一个CALayer类别,如下所示:
@interface CALayer (Utils)
- (void)bringSublayerToFront;
@end
@implementation CALayer (Utils)
- (void)bringSublayerToFront {
CGFloat maxZPosition = 0; // The higher the value, the closer it is to the front. By default is 0.
for (CALayer *layer in self.superlayer.sublayers) {
maxZPosition = (layer.zPosition > maxZPosition) ? layer.zPosition : maxZPosition;
}
self.zPosition = maxZPosition + 1;
}
@end
Swift 4版本。层本身具有
bringToFront
和sendToBack
方法的想法
#if os(iOS)
import UIKit
#elseif os(OSX)
import AppKit
#endif
extension CALayer {
func bringToFront() {
guard let sLayer = superlayer else {
return
}
removeFromSuperlayer()
sLayer.insertSublayer(self, at: UInt32(sLayer.sublayers?.count ?? 0))
}
func sendToBack() {
guard let sLayer = superlayer else {
return
}
removeFromSuperlayer()
sLayer.insertSublayer(self, at: 0)
}
}
用法:
let view = NSView(frame: ...)
view.wantsLayer = true
view.layer?.backgroundColor = NSColor.gray.cgColor
let l1 = CALayer(...)
let l2 = CALayer(...)
view.layer?.addSublayer(l1)
view.layer?.addSublayer(l2)
l1.bringToFront()
有没有机会解释一下为什么有人否决了这一点?可能是因为代码错了。未使用参数层。未定义gradientLayer。不需要superlayer调用,因为layer参数的superlayer是self。ivanzoid已发布更正的代码。
removeFromSuperlayer
方法是不必要的,因为调用insertSublayer
时会自动删除它。removeFromSuperlayer的另一个问题是:如果层是唯一的子层,删除它显然会导致子层数组为零。在Swift中,这会导致self.sublayers上的选项展开崩溃。(在Obj-C上可能没问题,因为[nil count]可能返回0,这实际上是可行的)。我完全忘记了zPosition,这个答案是最好的。这两个答案都有效,但从以下方面来看,这个答案更简单、更可靠:“在另一个子层的上方或下方插入时,您只需指定子层在子层数组中的位置。图层的实际可见性主要由其zPosition属性中的值决定,其次由其在子图层数组中的位置决定
let view = NSView(frame: ...)
view.wantsLayer = true
view.layer?.backgroundColor = NSColor.gray.cgColor
let l1 = CALayer(...)
let l2 = CALayer(...)
view.layer?.addSublayer(l1)
view.layer?.addSublayer(l2)
l1.bringToFront()