如何将文本阴影应用于 UITextView？

Question

其实我喜欢UILabel。他们很甜。现在我不得不去UITextView，因为UILabel 没有将文本垂直对齐到顶部。该死。我真正需要的一件事是文字阴影。 UILabel 有。 UITextView 似乎没有。但我猜那家伙只是使用相同的底层UIKitNSString 添加？也许有人已经有了解决这个问题的办法？我会覆盖什么？

Answer 1

text.layer.shadowColor = [[UIColor whiteColor] CGColor];
text.layer.shadowOffset = CGSizeMake(1.0f, 1.0f);
text.layer.shadowOpacity = 1.0f;
text.layer.shadowRadius = 1.0f;

别忘了加起来：

#import <QuartzCore/QuartzCore.h>

Answer 2

答案是

text.layer.shadowColor

为整个textView添加阴影，也许它有效，但它不仅给文本添加阴影。

正确答案是：

CALayer *textLayer = ((CALayer *)[textView.layer.sublayers objectAtIndex:0]);
textLayer.shadowColor = [UIColor whiteColor].CGColor;
textLayer.shadowOffset = CGSizeMake(0.0f, 1.0f);
textLayer.shadowOpacity = 1.0f;
textLayer.shadowRadius = 1.0f;

Answer 3

斯威夫特 3

---

let textView = UITextView(frame: view.frame)
textView.font = UIFont(name: "Helvetica", size: 64.0)
textView.textColor = .red
textView.text = "Hello World"

textView.layer.shadowColor = UIColor.black.cgColor
textView.layer.shadowOffset = CGSize(width: 2.0, height: 2.0)
textView.layer.shadowOpacity = 1.0
textView.layer.shadowRadius = 2.0
textView.layer.backgroundColor = UIColor.clear.cgColor

---

斯威夫特 2.3

---

let textView = UITextView(frame: view.frame)
textView.font = UIFont(name: "Helvetica", size: 64.0)
textView.textColor = UIColor.redColor()
textView.text = "Hello World"    

textView.layer.shadowColor = UIColor.blackColor().CGColor
textView.layer.shadowOffset = CGSize(width: 2.0, height: 2.0)
textView.layer.shadowOpacity = 1.0
textView.layer.shadowRadius = 2.0
textView.layer.backgroundColor = UIColor.clearColor().CGColor

Answer 4

这个Swift 示例 使用属性字符串方法为文本添加阴影。有关 Swift 中属性字符串的更多信息，请参阅 this answer。这种方法（与使用 layer method 不同）让您可以根据需要灵活地在文本范围内设置阴影。

// Create a string
let myString = "Shadow"

// Create a shadow
let myShadow = NSShadow()
myShadow.shadowBlurRadius = 3
myShadow.shadowOffset = CGSize(width: 3, height: 3)
myShadow.shadowColor = UIColor.gray

// Create an attribute from the shadow
let myAttribute = [ NSAttributedStringKey.shadow: myShadow ]

// Add the attribute to the string
let myAttrString = NSAttributedString(string: myString, attributes: myAttribute)

// set the attributed text on a label
myLabel.attributedText = myAttrString // can also use with UITextView

为 Swift 4 更新

Answer 5

在 iOS 6+ 中使用属性文本

NSShadow * shadow = [[NSShadow alloc] init];
shadow.shadowColor = [UIColor blackColor];
shadow.shadowOffset = CGSizeMake(2, 2);

NSDictionary * textAttributes =
@{ NSForegroundColorAttributeName : [UIColor blueColor],
   NSShadowAttributeName          : shadow,
   NSFontAttributeName            : [UIFont boldSystemFontOfSize:20] };

textView.attributedText = [[NSAttributedString alloc] initWithString:@"Hello" 
                                                          attributes:textAttributes];

Answer 6

这取决于您使用的 iOS 版本。从 iOS 6 开始，支持单个阴影，您将其设置为 NSAttributedString 上的属性，然后将其设置在标签上。

Answer 7

swift 4、swift 4.2、swift 5 及以上 简单优雅的解决方案，可以从界面生成器轻松使用

extension UIView {
    /* The color of the shadow. Defaults to opaque black. Colors created
     * from patterns are currently NOT supported. Animatable. */
    @IBInspectable var shadowColor: UIColor? {
        set {
            layer.shadowColor = newValue!.cgColor
        }
        get {
            if let color = layer.shadowColor {
                return UIColor(cgColor: color)
            }
            else {
                return nil
            }
        }
    }

    /* The opacity of the shadow. Defaults to 0.4 Specifying a value outside the
     * [0,1] range will give undefined results. Animatable. */
    @IBInspectable var shadowOpacity: Float {
        set {
            layer.shadowOpacity = newValue
        }
        get {
            return layer.shadowOpacity
        }
    }

    /* The shadow offset. Defaults to (1, 2). Animatable. */
    @IBInspectable var shadowOffset: CGPoint {
        set {
            layer.shadowOffset = CGSize(width: newValue.x, height: newValue.y)
        }
        get {
            return CGPoint(x: layer.shadowOffset.width, y:layer.shadowOffset.height)
        }
    }

    /* The blur radius used to create the shadow. Defaults to 3. Animatable. */
    @IBInspectable var shadowRadius: CGFloat {
        set {
            layer.shadowRadius = newValue
        }
        get {
            return layer.shadowRadius
        }
    }
}