我试图在运行时生成一个渐变颜色背景(纯色到透明)的视图。有办法做到吗?
当前回答
我已经在swift中实现了一个扩展:
斯威夫特3
extension UIView {
func addGradientWithColor(color: UIColor) {
let gradient = CAGradientLayer()
gradient.frame = self.bounds
gradient.colors = [UIColor.clear.cgColor, color.cgColor]
self.layer.insertSublayer(gradient, at: 0)
}
}
斯威夫特2.2
extension UIView {
func addGradientWithColor(color: UIColor) {
let gradient = CAGradientLayer()
gradient.frame = self.bounds
gradient.colors = [UIColor.clearColor().CGColor, color.CGColor]
self.layer.insertSublayer(gradient, atIndex: 0)
}
}
不,我可以像这样在每个视图上设置渐变:
myImageView.addGradientWithColor(UIColor.blue)
其他回答
试试这个对我来说很有魔力,
Objective - C
我已经设置了RGB渐变背景颜色为UIview
UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0,0,320,35)];
CAGradientLayer *gradient = [CAGradientLayer layer];
gradient.frame = view.bounds;
gradient.startPoint = CGPointZero;
gradient.endPoint = CGPointMake(1, 1);
gradient.colors = [NSArray arrayWithObjects:(id)[[UIColor colorWithRed:34.0/255.0 green:211/255.0 blue:198/255.0 alpha:1.0] CGColor],(id)[[UIColor colorWithRed:145/255.0 green:72.0/255.0 blue:203/255.0 alpha:1.0] CGColor], nil];
[view.layer addSublayer:gradient];
更新: Swift3 +
代码:
var gradientView = UIView(frame: CGRect(x: 0, y: 0, width: 320, height: 35))
let gradientLayer:CAGradientLayer = CAGradientLayer()
gradientLayer.frame.size = self.gradientView.frame.size
gradientLayer.colors =
[UIColor.white.cgColor,UIColor.red.withAlphaComponent(1).cgColor]
//Use diffrent colors
gradientView.layer.addSublayer(gradientLayer)
你可以添加渐变颜色的起点和终点。
gradientLayer.startPoint = CGPoint(x: 0.0, y: 1.0)
gradientLayer.endPoint = CGPoint(x: 1.0, y: 1.0)
更多细节请参考CAGradientLayer文档
希望这对一些人有所帮助。
给UIView渐变颜色(swift 4.2)
func makeGradientLayer(`for` object : UIView, startPoint : CGPoint, endPoint : CGPoint, gradientColors : [Any]) -> CAGradientLayer {
let gradient: CAGradientLayer = CAGradientLayer()
gradient.colors = gradientColors
gradient.locations = [0.0 , 1.0]
gradient.startPoint = startPoint
gradient.endPoint = endPoint
gradient.frame = CGRect(x: 0, y: 0, w: object.frame.size.width, h: object.frame.size.height)
return gradient
}
如何使用
let start : CGPoint = CGPoint(x: 0.0, y: 1.0)
let end : CGPoint = CGPoint(x: 1.0, y: 1.0)
let gradient: CAGradientLayer = makeGradientLayer(for: cell, startPoint: start, endPoint: end, gradientColors: [
UIColor(red:0.92, green:0.07, blue:0.4, alpha:1).cgColor,
UIColor(red:0.93, green:0.11, blue:0.14, alpha:1).cgColor
])
self.vwTemp.layer.insertSublayer(gradient, at: 0)
斯威夫特4:
正确显示IB中的梯度:
@IBDesignable public class GradientView: UIView {
override open class var layerClass: AnyClass {
return CAGradientLayer.classForCoder()
}
required public init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
configureGradientLayer()
}
public override init(frame: CGRect) {
super.init(frame: frame)
configureGradientLayer()
}
func configureGradientLayer() {
let gradientLayer = layer as! CAGradientLayer
gradientLayer.colors = [UIColor(hex: 0x003399).cgColor, UIColor(hex: 0x00297b).cgColor]
}
}
斯威夫特3
在视图上添加一个渐变层
Bind your view outlet @IBOutlet var YOURVIEW : UIView! Define the CAGradientLayer() var gradient = CAGradientLayer() Here is the code you have to write in your viewDidLoad YOURVIEW.layoutIfNeeded() gradient.startPoint = CGPoint(x: CGFloat(0), y: CGFloat(1)) gradient.endPoint = CGPoint(x: CGFloat(1), y: CGFloat(0)) gradient.frame = YOURVIEW.bounds gradient.colors = [UIColor.red.cgColor, UIColor.green.cgColor] gradient.colors = [ UIColor(red: 255.0/255.0, green: 56.0/255.0, blue: 224.0/255.0, alpha: 1.0).cgColor,UIColor(red: 86.0/255.0, green: 13.0/255.0, blue: 232.0/255.0, alpha: 1.0).cgColor,UIColor(red: 16.0/255.0, green: 173.0/255.0, blue: 245.0/255.0, alpha: 1.0).cgColor] gradient.locations = [0.0 ,0.6 ,1.0] YOURVIEW.layer.insertSublayer(gradient, at: 0)
因为我只需要一种类型的梯度在我的应用程序,我创建了一个子类的UIView和预配置梯度层初始化固定的颜色。 UIView的初始化器调用configuregradientlayer -方法,它配置CAGradientLayer:
DDGradientView.h:
#import <UIKit/UIKit.h>
@interface DDGradientView : UIView {
}
@end
DDGradientView.m:
#import "DDGradientView.h"
@implementation DDGradientView
// Change the views layer class to CAGradientLayer class
+ (Class)layerClass
{
return [CAGradientLayer class];
}
- (instancetype)initWithCoder:(NSCoder *)aDecoder {
self = [super initWithCoder:aDecoder];
if(self) {
[self configureGradientLayer];
}
return self;
}
- (instancetype)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if(self) {
[self configureGradientLayer];
}
return self;
}
// Make custom configuration of your gradient here
- (void)configureGradientLayer {
CAGradientLayer *gLayer = (CAGradientLayer *)self.layer;
gLayer.colors = [NSArray arrayWithObjects:(id)[[UIColor whiteColor] CGColor], (id)[[UIColor lightGrayColor] CGColor], nil];
}
@end
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