iOS踩过的坑之富文本计算文字高度
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参考技术A 在设置了label中文字的字间距、行间距、段间距后，获取label总的高度，尝试了各种计算方法，最后只发现一种方式是有效的。每次使用原字符串内容计算完高度时，最后一行都无法显示，
在文章末尾添加一个换行符，然后再计算总高度。
其中，options的枚举值说明：
Swift5 踩过的坑和奇怪的API笔记
踩过的坑和奇怪的API笔记
UINavigationController 导航栏
设置导航栏颜色
navigationController?.navigationBar.barTintColor = .blue
去掉导航栏下面的分割线
navigationController?.navigationBar.setBackgroundImage(UIImage(), for: .default)
navigationController?.navigationBar.shadowImage = UIImage()
- 此时导航栏颜色和View背景相同，应该类似吧导航栏设置透明了的效果
- 使用方法一设置导航栏颜色为
.clear并不能达到相同效果 - 本方法会导致方法一设置导航栏颜色失效,此时使用以下代码设置导航栏颜色
navigationController?.navigationBar.backgroundColor = .orange
设置导航栏字体和字体颜色
self.navigationController?.navigationBar.titleTextAttributes = [NSAttributedString.Key.foregroundColor:UIColor.black,NSAttributedString.Key.font : UIFont.systemFont(ofSize: 25)]
UITabBar
UITabBar和导航栏结合使用
tabBarCtrl = UITabBarController()
tabBarCtrl.tabBar.tintColor = .DesignGreen
let view1 = ViewHome()
view1.tabBarItem.image = UIImage(named: "xiaozujian")
view1.tabBarItem.title = "组件"
let view2 = ViewIcon()
view2.tabBarItem.image = UIImage(named: "tubiao")
view2.tabBarItem.title = "图标"
let view1 = UINavigationController.init(rootViewController: viewHome)
let view2 = UINavigationController.init(rootViewController: viewIcon)
tabBarCtrl.addChild(view1)
tabBarCtrl.addChild(view2)
tabBarCtrl.selectedIndex = 0 //默认选择
self.window?.rootViewController = tabBarCtrl
window?.makeKeyAndVisible()
获取UITabBar的高度
let height = tabBarCtrl.tabBar.bounds.size.height
跳转界面隐藏UITabBar的方案
override func viewWillDisappear(_ animated: Bool)
tabBarCtrl.tabBar.isHidden = true
UITableView
UITableViewCell里点击事件不生效
使用 cell.contentView.addSubview 代替 cell.addSubview
设置分割线内边距
tableView.separatorInset = UIEdgeInsets(top: 0, left: 20, bottom: 0, right: 20)
隐藏所有分割线分割线
- 方法一：
self.separatorStyle = .none
- 方法二：
tableView.separatorInset = UIEdgeInsets(top: 0, left: tableView.frame.width, bottom: 0, right: 0)
隐藏底部多余行及分割线
tableview.tableFooterView = UIView(frame: CGRect.zero)
UICollectionView & UIScrollView
cell里的按钮区域只能点击无法滑动
使用`UILabel`或`UIImageView`等绑定`UITapGestureRecognizer` 代替`UIButton`
func InitUI()
let img = UIImageView(frame:CGRect(xxxxxx))
let singleTapGesture = UITapGestureRecognizer(target: self, action: #selector(ClickBtn(_:)))
img.addGestureRecognizer(singleTapGesture)
img.isUserInteractionEnabled = true
@objc func ClickBtn(_ tap:UITapGestureRecognizer)
允许多选
collection.allowsMultipleSelection = true
ScrollView是否显示滑动条
scrollView.showsHorizontalScrollIndicator = false
scrollView.showsVerticalScrollIndicator = false
ScrollView使ContentSize小于UIScrollView大小也能滑动
scrollView.alwaysBounceVertical = true
scrollView.alwaysBounceHorizontal = true
ScrollView分页滑动
func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool)
if (!decelerate)
scrollView.setContentOffset(CGPoint(x: CGFloat(Int(scrollView.contentOffset.x/pageWidth + 0.5))*pageWidth, y: scrollView.contentOffset.y), animated: true)
selectPage = Int(scrollView.contentOffset.x/pageWidth + 0.5)
func scrollViewWillBeginDecelerating(_ scrollView: UIScrollView)
scrollView.setContentOffset(CGPoint(x: CGFloat(Int(scrollView.contentOffset.x/pageWidth + 0.5))*pageWidth, y: scrollView.contentOffset.y), animated: true)
selectPage = Int(scrollView.contentOffset.x/pageWidth + 0.5)
UIScrollView截长图
///截长图
extension UIScrollView
/// 截长屏Image
var captureLongImage: UIImage?
var image: UIImage? = nil
let savedContentOffset:CGPoint? = contentOffset
let savedFrame:CGRect? = frame
contentOffset = .zero
frame = CGRect(x: 0, y: 0,
width: contentSize.width,
height: contentSize.height)
UIGraphicsBeginImageContextWithOptions(
CGSize(width: frame.size.width,
height: frame.size.height),
false,
0.0)
layer.render(in: UIGraphicsGetCurrentContext()!)
image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
contentOffset = savedContentOffset ?? contentOffset
frame = savedFrame ?? frame
return image
fileprivate func writeImageToAlbum(_ image: UIImage)
UIImageWriteToSavedPhotosAlbum(image, self, #selector(image(image:didFinishSavingWithError:contextInfo:)), nil)
@objc fileprivate func image(image: UIImage, didFinishSavingWithError error: NSError?, contextInfo:UnsafeRawPointer)
if let _ = error as NSError?
print("保存失败，请重试")
else
print("保存成功！")
UIView
截图
extension UIView
/// 截屏Image
func captureImage(size:CGSize)-> UIImage?
// 参数①：截屏区域 参数②：是否透明 参数③：清晰度
UIGraphicsBeginImageContextWithOptions(frame.size, false, 0.0)
layer.render(in: UIGraphicsGetCurrentContext()!)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return image
func captureImageInPos( rect: CGRect) -> UIImage?
UIGraphicsBeginImageContext(rect.size)
guard let context = UIGraphicsGetCurrentContext() else return nil
context.translateBy(x: -rect.minX, y: -rect.minY)
self.draw(.zero)
let croppedImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return croppedImage
拼接图片
//拼接图片
func combinTwoImage(image1:UIImage,image2:UIImage) -> UIImage
let width = max(image1.size.width, image2.size.width)
let height = image1.size.height + image2.size.height
let offScreenSize = CGSize.init(width: width, height: height)
UIGraphicsBeginImageContextWithOptions(offScreenSize, false, 0.0)
let rect = CGRect.init(x:0, y:0, width:width, height:image1.size.height)
image1.draw(in: rect)
let rect2 = CGRect.init(x:0, y:image1.size.height, width:width, height:image2.size.height)
image2.draw(in: rect2)
let image:UIImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext();
return image;
获取当前UIView的UIVIewController
extension UIView
func ParentCtrl()->UIViewController
var vc:UIResponder = self
while vc.isKind(of: UIViewController.self) != true
vc = vc.next!
return vc as! UIViewController
UIImage
重设图片大小和等比例缩放
extension UIImage
/**
* 重设图片大小
*/
func reSizeImage(reSize: CGSize )-> UIImage
//UIGraphicsBeginImageContext(reSize);
UIGraphicsBeginImageContextWithOptions (reSize, false , UIScreen .main.scale);
//绘制图片
self.draw(in: CGRect(x: 0,
y: 0,
width: reSize.width,
height: reSize.height))
let reSizeImage: UIImage = UIGraphicsGetImageFromCurrentImageContext ()!
UIGraphicsEndImageContext ();
return reSizeImage;
/**
* 等比率缩放
*/
func scaleImage(scaleSize: CGFloat )-> UIImage
let reSize = CGSize(width: self .size.width * scaleSize, height: self .size.height * scaleSize)
return reSizeImage(reSize: reSize)
裁切图片
extension UIImage
func crop(_ rect: CGRect) -> UIImage?
let img = self.reSizeImage(reSize: UIScreen.main.currentMode!.size)
var newRect = rect
let WIDTH:CGFloat = UIScreen.main.bounds.width
let RELWIDTH = UIScreen.main.currentMode?.size.width
let scale = (RELWIDTH!/WIDTH)
newRect.origin.x *= scale*scale
newRect.origin.y *= scale*scale
newRect.size.width *= scale*scale
newRect.size.height *= scale*scale
guard let imageRef = img.cgImage?.cropping(to: newRect) else return nil
return UIImage(cgImage: imageRef)
获取纯色UIImage
extension UIImage
convenience init?(color: UIColor, size: CGSize = CGSize(width: 1, height: 1))
let rect = CGRect(origin: .zero, size: size)
UIGraphicsBeginImageContextWithOptions(rect.size, false, 0.0)
color.setFill()
UIRectFill(rect)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
guard let cgImage = image?.cgImage else return nil
self.init(cgImage: cgImage)
改变颜色
extension UIImage
func changeColor(color:UIColor) -> UIImage
UIGraphicsBeginImageContextWithOptions(self.size, false, self.scale)
let context = UIGraphicsGetCurrentContext()
context?.translateBy(x: 0, y: self.size.height)
context?.scaleBy(x: 1.0, y: -1.0)//kCGBlendModeNormal
context?.setBlendMode(.normal)
let rect = CGRect(x: 0, y: 0, width: self.size.width, height: self.size.height)
context?.clip(to: rect, mask: self.cgImage!);
color.setFill()
context?.fill(rect)
let newImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return newImage!
获取网络图片
func GetImgByUrl(path:String)->UIImage
let url = NSURL(string: path)!
let data = NSData(contentsOf: url as URL)!
return UIImage(data: data as Data,scale: 1.0)!
UIImageView
圆角不生效
imgView.layer.masksToBounds = true
UIButton
UIButton中图片和文字的位置变换
enum ButtonEdgeInsetsStyle
case ButtonEdgeInsetsStyleTop // image在上，label在下
case ButtonEdgeInsetsStyleLeft // image在左，label在右
case ButtonEdgeInsetsStyleBottom // image在下，label在上
case ButtonEdgeInsetsStyleRight // image在右，label在左
extension UIButton
func layoutButtonEdgeInsets(style:ButtonEdgeInsetsStyle,space:CGFloat)
let labelWidth : CGFloat = self.titleLabel?.frame.size.height ?? 36
let labelHeight : CGFloat = self.titleLabel?.frame.size.width ?? 20
var imageEdgeInset =以上是关于iOS踩过的坑之富文本计算文字高度的主要内容，如果未能解决你的问题，请参考以下文章