UIView底边框？

Question

UIScrollView *toScrollView我要添加一个（它是屏幕的宽度）的灰色底边框（与iPhone的本地Messages应用程序的compose视图的to-field的边框完全一样）。为此，我遵循了可可触摸：如何更改UIView的边框颜色和厚度？并使用自定义设置覆盖了顶部边框，UINavigationBar并将其toScrollViewx坐标-1和宽度322设置为使左右边框刚好不在屏幕上。看起来不错，但这有点不合时宜，我想知道是否有更好的方法可以做到这一点。- (void)viewDidLoad {    [super viewDidLoad];    // Add UINavigationBar *navigationBar at top.    self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc]                                             initWithBarButtonSystemItem:UIBarButtonSystemItemCancel                                             target:self action:@selector(cancelAction)];    UINavigationBar *navigationBar = [[UINavigationBar alloc]                                      initWithFrame:CGRectMake(0.0f, 0.0f, 320.0f, 44.0f)];    navigationBar.items = [NSArray arrayWithObject:self.navigationItem];    // Add UIScrollView *toScrollView below navigationBar.    UIScrollView *toScrollView = [[UIScrollView alloc]                                  initWithFrame:CGRectMake(-1.0f, 43.0f, 322.0f, 45.0f)];    toScrollView.backgroundColor = [UIColor whiteColor];    toScrollView.layer.borderColor = [UIColor colorWithWhite:0.8f alpha:1.0f].CGColor;    toScrollView.layer.borderWidth = 1.0f;    [self.view addSubview:toScrollView];    [self.view addSubview:navigationBar]; // covers top of toScrollView}

Answer 1

代替UIView@ImreKelényi建议使用，可以使用CALayer：

// Add a bottomBorder.

CALayer *bottomBorder = [CALayer layer];

bottomBorder.frame = CGRectMake(0.0f, 43.0f, toScrollView.frame.size.width, 1.0f);

bottomBorder.backgroundColor = [UIColor colorWithWhite:0.8f 

                                                 alpha:1.0f].CGColor;

[toScrollView.layer addSublayer:bottomBorder];

Answer 2

这是更通用的Swift扩展，可为任何子UIView类创建边框：

import UIKit

extension UIView {      

  func addTopBorderWithColor(color: UIColor, width: CGFloat) {

    let border = CALayer()

    border.backgroundColor = color.CGColor

    border.frame = CGRectMake(0, 0, self.frame.size.width, width)

    self.layer.addSublayer(border)

  }

  func addRightBorderWithColor(color: UIColor, width: CGFloat) {

    let border = CALayer()

    border.backgroundColor = color.CGColor

    border.frame = CGRectMake(self.frame.size.width - width, 0, width, self.frame.size.height)

    self.layer.addSublayer(border)

  }

  func addBottomBorderWithColor(color: UIColor, width: CGFloat) {

    let border = CALayer()

    border.backgroundColor = color.CGColor

    border.frame = CGRectMake(0, self.frame.size.height - width, self.frame.size.width, width)

    self.layer.addSublayer(border)

  }

  func addLeftBorderWithColor(color: UIColor, width: CGFloat) {

    let border = CALayer()

    border.backgroundColor = color.CGColor

    border.frame = CGRectMake(0, 0, width, self.frame.size.height)

    self.layer.addSublayer(border)

  }

}

迅捷3

extension UIView {

    func addTopBorderWithColor(color: UIColor, width: CGFloat) {

        let border = CALayer()

        border.backgroundColor = color.cgColor

        border.frame = CGRect(x: 0, y: 0, width: self.frame.size.width, height: width)

        self.layer.addSublayer(border)

    }

    func addRightBorderWithColor(color: UIColor, width: CGFloat) {

        let border = CALayer()

        border.backgroundColor = color.cgColor

        border.frame = CGRect(x: self.frame.size.width - width, y: 0, width: width, height: self.frame.size.height)

        self.layer.addSublayer(border)

    }

    func addBottomBorderWithColor(color: UIColor, width: CGFloat) {

        let border = CALayer()

        border.backgroundColor = color.cgColor

        border.frame = CGRect(x: 0, y: self.frame.size.height - width, width: self.frame.size.width, height: width)

        self.layer.addSublayer(border)

    }

    func addLeftBorderWithColor(color: UIColor, width: CGFloat) {

        let border = CALayer()

        border.backgroundColor = color.cgColor

        border.frame = CGRect(x: 0, y: 0, width: width, height: self.frame.size.height)

        self.layer.addSublayer(border)

    }

}

Answer 3

在以下类别中实施：

UIButton + Border.h：

@interface UIButton (Border)

- (void)addBottomBorderWithColor: (UIColor *) color andWidth:(CGFloat) borderWidth;

- (void)addLeftBorderWithColor: (UIColor *) color andWidth:(CGFloat) borderWidth;

- (void)addRightBorderWithColor: (UIColor *) color andWidth:(CGFloat) borderWidth;

- (void)addTopBorderWithColor: (UIColor *) color andWidth:(CGFloat) borderWidth;

@end

UIButton + Border.m：

@implementation UIButton (Border)

- (void)addTopBorderWithColor:(UIColor *)color andWidth:(CGFloat) borderWidth {

    CALayer *border = [CALayer layer];

    border.backgroundColor = color.CGColor;

    border.frame = CGRectMake(0, 0, self.frame.size.width, borderWidth);

    [self.layer addSublayer:border];

}

- (void)addBottomBorderWithColor:(UIColor *)color andWidth:(CGFloat) borderWidth {

    CALayer *border = [CALayer layer];

    border.backgroundColor = color.CGColor;

    border.frame = CGRectMake(0, self.frame.size.height - borderWidth, self.frame.size.width, borderWidth);

    [self.layer addSublayer:border];

}

- (void)addLeftBorderWithColor:(UIColor *)color andWidth:(CGFloat) borderWidth {

    CALayer *border = [CALayer layer];

    border.backgroundColor = color.CGColor;

    border.frame = CGRectMake(0, 0, borderWidth, self.frame.size.height);

    [self.layer addSublayer:border];

}

- (void)addRightBorderWithColor:(UIColor *)color andWidth:(CGFloat) borderWidth {

    CALayer *border = [CALayer layer];

    border.backgroundColor = color.CGColor;

    border.frame = CGRectMake(self.frame.size.width - borderWidth, 0, borderWidth, self.frame.size.height);

    [self.layer addSublayer:border];

}

@end