有没有办法在界面构建器中制作渐变背景颜色？

Question

For my application I'm using a TableView and using customized UITableViewCells.

I customized my cells via interface builder, not programmatically. Is there a way to also make the background color of my customized cell a gradient in the interface builder?

Thanks.

Answer 1

This works for Swift 3.0: (Updated for Swift 4.0)

@IBDesignable
final class GradientView: UIView {
    @IBInspectable var startColor: UIColor = UIColor.clear
    @IBInspectable var endColor: UIColor = UIColor.clear

    override func draw(_ rect: CGRect) {
        let gradient: CAGradientLayer = CAGradientLayer()
        gradient.frame = CGRect(x: CGFloat(0),
                                y: CGFloat(0),
                                width: superview!.frame.size.width,
                                height: superview!.frame.size.height)
        gradient.colors = [startColor.cgColor, endColor.cgColor]
        gradient.zPosition = -1
        layer.addSublayer(gradient)
    }
}

Answer 2

To draw a gradient, you will have to subclass and override the drawRect programmatically:

- (void)drawRect:(CGRect)rect
{
    CGContextRef context = UIGraphicsGetCurrentContext();

    CGContextSaveGState(context);
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    CGGradientRef gradient = CGGradientCreateWithColorComponents
                             (colorSpace,
                              (const CGFloat[8]){1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, 1.0f},
                              (const CGFloat[2]){0.0f,1.0f},
                              2);

    CGContextDrawLinearGradient(context,
                                gradient,
                                CGPointMake(CGRectGetMidX(self.bounds), CGRectGetMinY(self.bounds)),
                                CGPointMake(CGRectGetMidX(self.bounds), CGRectGetMaxY(self.bounds)),
                                0);

    CGColorSpaceRelease(colorSpace);
    CGContextRestoreGState(context);
}

The easiest way, which keeps your cells in the interface builder, is probably to subclass a UIView to have it draw a gradient in its drawRect and place it in your cell behind the other subviews:

GradientView *gradientView = [[GradientView alloc] init];
gradientView.frame = cell.bounds;
[cell addSubview:gradientView];
[cell sendSubviewToBack:gradientView];

However, the best way to do it is probably not to use the interface builder for this and make a subclass of UITableViewCell. For advanced customization, interface builders tend to only make things more complicated in my experience. That's up to personal preference though.

Answer 3

CAGradientLayer *gradient = [CAGradientLayer layer];
gradient.frame = yourView.bounds;
gradient.colors = [NSArray arrayWithObjects:(id)[[UIColor blackColor] CGColor], (id)    [[UIColor whiteColor] CGColor], nil];
[yourView.layer insertSublayer:gradient atIndex:0];

Answer 4

Yes this is possible : Make a image in gradient with 1 X Height pix. Set this to backgroundColor for cell.

cell.backgroundColor =  [UIColor colorWithPatternImage:[UIImage imageNamed:@"gradImage.png"]];

**You can set gradient color with code but its time taken process. If you fill better then search for that.

Answer 5

answer by etayluz works fine but I added a couple changes:

1. Gradient size defined by own layer bounds, not the superview.

2. Remove Gradient layer on every draw, so that it does not keep drawing and adding a new layer when redraw is necessary (for instance by calling .setNeedsDisplay() on rotation).

    @IBDesignable final class MFGradientView: UIView { @IBInspectable var startColor: UIColor = UIColor.clear @IBInspectable var endColor: UIColor = UIColor.clear override func draw(_ rect: CGRect) { layer.sublayers?.first?.removeFromSuperlayer() let gradient: CAGradientLayer = CAGradientLayer() gradient.frame = CGRect(origin: CGPoint.zero, size: self.bounds.size) gradient.colors = [startColor.cgColor, endColor.cgColor] layer.insertSublayer(gradient, at: 0) } } 

Answer 6

Based on etayluz answer I changed the code a little bit by taking the layerClass property of a UIView into account, so you do not need a separate layer as a sublayer.

I think it is much cleaner and it also works with live updates in the Interface Builder.

@IBDesignable final class GradientView: UIView {

    @IBInspectable var startColor: UIColor = UIColor.red
    @IBInspectable var endColor: UIColor = UIColor.blue

    override class var layerClass: AnyClass {
        get {
            return CAGradientLayer.self
        }
    }

    override init(frame: CGRect) {
        super.init(frame: frame)
        setupGradient()
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        setupGradient()
    }

    private func setupGradient() {
        let gradient = self.layer as! CAGradientLayer
        gradient.colors = [startColor.cgColor, endColor.cgColor]
    }

}

Answer 7

Create a simple view class with @IBInspectable properties.

1. Create gradient layer once
2. Reuse gradient layer each layout subviews

...

//
//  GradientView.swift
//
//  Created by Maksim Vialykh on 23.08.2018.
//  Copyright © 2018 Vialyx. All rights reserved.
//

import UIKit

class GradientView: UIView {

    @IBInspectable
    var startColor: UIColor = .white

    @IBInspectable
    var endColor: UIColor = .black

    private let gradientLayerName = "Gradient"

    override func layoutSubviews() {
        super.layoutSubviews()

        setupGradient()
    }

    private func setupGradient() {
        var gradient: CAGradientLayer? = layer.sublayers?.first { $0.name == gradientLayerName } as? CAGradientLayer
        if gradient == nil {
            gradient = CAGradientLayer()
            gradient?.name = gradientLayerName
            layer.addSublayer(gradient!)
        }
        gradient?.frame = bounds
        gradient?.colors = [startColor.cgColor, endColor.cgColor]
        gradient?.zPosition = -1
    }

}

Answer 8

我不知道是否有渐变选项，但您可以将UIImageView添加到自定义单元格并添加带有渐变的图像。

Answer 9

No, you can't. You could use UISegmentedControl with one segment in older sdk and xCode versions: http://chris-software.com/index.php/2009/05/13/creating-a-nice-glass-buttons/ But now you can't make less than two segments in one UISegmentedControl. And even this way you couldn't change the default colors of the buttons without coding.