一个CALayer的分配给一个UIImageView才能够做所有你可以用一个UIImageView做

问题描述

喜每个人有一个链接：，有一个样品code在它在这里笔者使用的CALayer用CAShapeLayer.What我想就是用这个的CALayer就像是一个UIImageView（可能分配给一个UIImageView）能够进行移动等...

Hi every one there is a link :link and there is a sample code in it where the author use a CALayer with CAShapeLayer.What I would like is to use this CALayer like it was a uiimageView (maybe assign to a uiimageview) to be able to move it etc...

推荐答案

您不能改变的图层类型现有的的UIView （意思是：你也改变不了的层的的UIImageView ），但画上一个层是pretty简单：你需要一个委托分配给您的的CALayer ，并且该委托需要实现 drawLayer：inContext的：

You cannot change the layer type of an existing UIView (meaning: you also can't change the layer of an UIImageView), but drawing to a layer is pretty easy: you need to assign a delegate to your CALayer, and that delegate needs to implement drawLayer:inContext:.

另一种解决方案可能是创建一个的UIView 子类，并实施 + layerClass ：

Another solution might be to create a UIView subclass and implement +layerClass:

+ (Class)layerClass
{
    return [CAShapeLayer class];
}

这样，你的观点将使用形状图层，你也许可以简单地使用通常的的UIView 的drawRect：方法。然后，您可以通过访问层（CAShapeLayer *）[个体经营层] 进行修改。我没有试过这种方法，虽然。

That way your view will use a shape layer and you might be able to simply use the usual UIView's drawRect: method. You could then access the layer via (CAShapeLayer *)[self layer] to modify it. I haven't tried this approach, though.

编辑：如何解释第二的解决办法来完成：

Explaining how the second solution would be done:

@interface MyView : UIView {
    UIImage *image;
}
@property(retain) UIImage *image;
@end


@implementation MyView
@synthesize image;

+ (Class)layerClass
{
    return [CAShapeLayer class];
}

- (void)dealloc
{
    self.image = nil;
    [super dealloc];
}

- (void)drawRect:(CGRect)rect
{
    // Draw the image. You might need to play around with this,
    // for example to draw the image as aspect fit or aspect fill.
    [image drawInRect:rect];
}
@end

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