在UIImageView后面创建阴影的最佳方法是什么 [英] What is the best way to create a shadow behind a UIImageView

问题描述

我有一个UIImageView，我想在后面添加一个阴影。我希望苹果将其作为一种财产，但他们必须为我们的程序员做很多事情，所以我需要问这个问题。

I have a UIImageView that I want to add a shadow behind. I wish that apple had that as a property but they have to make lots of things hard for us programmers so I need to ask this question.

推荐答案

有一种更好，更简单的方法。 UIImageView继承自UIView，因此它具有图层属性。你可以访问图层的阴影属性和bam，你有一个阴影。

There's a better and easier way to do this. UIImageView inherits from UIView so it has a layer property. You can access the layer's shadow properties and bam, you got a shadow.

如果你把UIImageView作为nib文件的IBOutlet，你可以实现awakeFromNib
例如

If you have the UIImageView as an IBOutlet to a nib file, you can just implement the awakeFromNib e.g.

Objective-C

- (void)awakeFromNib {
    imageView.layer.shadowColor = [UIColor purpleColor].CGColor;
    imageView.layer.shadowOffset = CGSizeMake(0, 1);
    imageView.layer.shadowOpacity = 1;
    imageView.layer.shadowRadius = 1.0;
    imageView.clipsToBounds = NO;
}

不要忘记 #importQuartzCore / CALayer.h

对于Swift，你可以采取多种方式。创建类扩展，子类或imageView实例。无论哪种方式，修改图层阴影属性的过程都相同。

For Swift, you can go about it multiple ways. Create a class extension, subclass, or an imageView instance. Whichever the way, the process is the same in modifying the layers shadow property.

Swift 3

override func awakeFromNib() {
    super.awakeFromNib()

    imageView.layer.shadowColor = UIColor.purple.cgColor
    imageView.layer.shadowOffset = CGSize(width: 0, height: 1)
    imageView.layer.shadowOpacity = 1
    imageView.layer.shadowRadius = 1.0
    imageView.clipsToBounds = false
}

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