imzyf/ios-swift-learning-notes

📝 iOS Swift Learning Notes - see Issues

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ios-swift-learning-notes's Issues

for 循环遍历

http://blog.csdn.net/dylan_lwb_/article/details/40299371

遍历字典

var ageDict:Dictionary<String, Int> = ["mary": 19, "rose": 20]  
  
var names = [String]()  
var ages = [Int]()  
for (key, value) in ageDict {  
    names.append(key)  
    ages.append(value)  
}  
names  
ages

毛玻璃效果

http://www.hangge.com/blog/cache/detail_1135.html

UIFont set systemFont

https://stackoverflow.com/questions/36469749/what-is-ios-9-3-system-font-name

UIFont.systemFont(ofSize: 15)

UIAlertController alert 弹框提示

https://stackoverflow.com/questions/24022479/how-would-i-create-a-uialertview-in-swift

let alertView = UIAlertController(title: "无法访问您的麦克风", message: "请到设置 -> 隐私 -> 麦克风 ，打开访问权限", preferredStyle: .alert)
alertView.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))
alertView.addAction(UIAlertAction(title: "好的", style: .default, handler: nil))
                
self.present(alertView, animated: true, completion: nil)

UIBezierPath 画图

https://stackoverflow.com/questions/21311880/drawing-uibezierpath-on-code-generated-uiview

fileprivate open 访问控制

http://www.jianshu.com/p/604305a61e57

现在的访问权限则依次为：open，public，internal，fileprivate，private。
有的人会觉得访问权限选择的增加加大了语言的复杂度。但是如果我们思考swift语言的设计目标之一就是一门安全的语言（“Designed for Safety”）就能理解这次的改动。更加明确清晰的访问权限控制可以使程序员表达出更准确的意图，当然也迫使在编码时思考的更加深入。

作者：没故事的卓同学
链接：http://www.jianshu.com/p/604305a61e57
來源：简书
著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。

CGPoint 计算两点的距离

https://stackoverflow.com/questions/1906511/how-to-find-the-distance-between-two-cg-points

CGFloat distance = hypotf(p1.x - p2.x, p1.y - p2.y);

extension CGPoint {

    func distance(toPoint p:CGPoint) -> CGFloat {
        return sqrt(pow(x - p.x, 2) + pow(y - p.y, 2))
    }
}

M_PI_4 and M_PI_2 in Swift 4

https://stackoverflow.com/questions/44424738/what-is-the-syntax-for-m-pi-4-and-m-pi-2-in-swift-3

M_PI_4 is now .pi / 4

How to set Status Bar Style in Swift 3

https://stackoverflow.com/questions/38740648/how-to-set-status-bar-style-in-swift-3

ios 10 and swift 3

1. Change in info.plist the row View controller-based status bar appearance and set it to NO
2. Change in appDelegate.swift in didFinishLaunchingWithOptions

UIApplication.shared.statusBarStyle = .lightContent

xib 中实例化 View

https://stackoverflow.com/questions/35659714/loading-a-xib-file-to-a-uiview-swift

let v =  UINib(nibName: "TranslateContentView", bundle: nil)
                      .instantiate(withOwner: nil, options: nil).first as! UIView

UIScrollView 滑动速度 适用于 tableView、collectionView

http://www.hangge.com/blog/cache/detail_1432.html

self.tableView!.decelerationRate = UIScrollViewDecelerationRateFast

• UIScrollViewDecelerationRateNormal：0.998（默认值）
• UIScrollViewDecelerationRateFast：0.99

self.tableView!.decelerationRate = 0.994

UIColor init 十六进制

extension UIColor {
    // 用数值初始化颜色，便于生成设计图上标明的十六进制颜色
    convenience init(valueRGB: UInt, alpha: CGFloat = 1.0) {
        self.init(
            red: CGFloat((valueRGB & 0xFF0000) >> 16) / 255.0,
            green: CGFloat((valueRGB & 0x00FF00) >> 8) / 255.0,
            blue: CGFloat(valueRGB & 0x0000FF) / 255.0,
            alpha: alpha
        )
    }
}

最小的Swift App

如何通过通过纯粹的代码，而不依赖于Xcode的StoryBoard，来完成一个App？

https://juejin.im/post/58c5f49d61ff4b005d9d8614

designated、convenience、required、构造器

• Swift中初始化过程学习笔记（二）-类继承和初始化
• DESIGNATED，CONVENIENCE 和 REQUIRED

StatusBar 相关

显示 隐藏 样式 动画

plist 中的 UIViewControllerBasedStatusBarAppearance 设置为 no 或者移除

setStatusBarStyle 不再使用

    override var prefersStatusBarHidden: Bool {
        return true
    }

延时执行

http://blog.csdn.net/c_calary/article/details/52917344
http://swifter.tips/gcd-delay-call/

UIButton image

图片居中

https://stackoverflow.com/questions/37474237/how-do-you-set-the-height-and-width-of-a-uibutton-with-image

bakButton.imageView?.contentMode = .center

Frames、Bounds 和 CGGeometry

https://segmentfault.com/a/1190000004695617

String 替换、过滤、去掉空格、分割、拼接、字符串截取

http://www.jianshu.com/p/26d9201ef479

let s = " / 2 3 4 ? / "
    // 替换
    print("空格替换成-:", s.replacingOccurrences(of: " ", with: "-"))
    // 过滤
    print("空格过滤掉:", s.replacingOccurrences(of: " ", with: ""))
    // 去首尾空格
    print("去掉空格:", s.trimmingCharacters(in: .whitespaces))
    // 分割
    print("分割:", s.components(separatedBy: "/"))
    // 拼接
    let a = ["1", "2", "3"]
    print("拼接:", a.joined(separator: "-"))

UIProgressView 高度

http://www.hangge.com/blog/cache/detail_1165.html

//通过变形改变进度条高度（ 横向宽度不变，纵向高度变成默认的5倍）
myProgressView.transform = CGAffineTransformMakeScale(1.0, 5.0)
         
//进度条条进度
myProgressView.progress = 0.3

设置 UIView 圆角和阴影

// 设置圆角和边框
self.buyPrompt.layer.cornerRadius = 6.0
self.buyPrompt.layer.borderColor = UIColor.lightGray.cgColor
self.buyPrompt.layer.borderWidth = 0.5

// 设置阴影
self.buyPrompt.layer.shadowColor = UIColor.lightGray.cgColor
self.buyPrompt.layer.shadowOpacity = 0.8
self.buyPrompt.layer.shadowRadius = 0.6
self.buyPrompt.layer.shadowOffset = CGSize(width: 0, height: 10)

CGRect 缩放、移动

CGRectInset 的使用方法：

//CGRectInset 将原来的矩形放大或者缩小，正表示缩小，负表示放大。
        CGRect rect = CGRectMake(80, 50, 130, 100);
        /**
         *  @param rect 以rect为中心 放大或缩小
         *  @param -20  X轴方向放大两个20
         *  @param 30   Y轴方向缩小两个30
         */
        CGRect upRect = CGRectInset(rect, -20, 30);
        NSLog(@"%@", NSStringFromRect(upRect));

        //输出结果：{{20, 80}, {170, 40}}

CGRectoffset的使用方法：

//CGRectOffset 将原来的左上角点的坐标变化
CGRect rect = CGRectMake(80, 50, 130, 100);
/**以左上角为顶点
* @param rect <#rect description#>
* @param -20 X坐标左移20
* @param 30 Y坐标上移30
宽度和高度不变
*/
CGRect upRect = CGRectOffset(rect, -20, 30);
NSLog(@"%@",NSStringFromRect(upRect));
//输出结果： {{60, 80}, {130, 100}}

作者：醉春风
链接：http://www.jianshu.com/p/26b85bff859a
來源：简书
著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。

bezierpath-length 获取 bezier 曲线长度

https://github.com/louisdh/bezierpath-length

UIViewContentMode 图片显示模式

http://www.jianshu.com/p/8c3bc470ee7a

editActionsForRowAt TableViewCell 侧滑

    func tableView(_ tableView: UITableView, editActionsForRowAt indexPath: IndexPath) -> [UITableViewRowAction]? {
        let deleteAction = UITableViewRowAction(style: .default, title: "Delete") { (action, index) in
            debugPrint("\(index.row)-Delete")
        }
        deleteAction.backgroundColor = UIColor.red
        
        let moreAction = UITableViewRowAction(style: .normal, title: "👍") { (action, index) in
            debugPrint("\(index.row)-More")
        }
        moreAction.backgroundColor = UIColor.lightGray
        
        return [deleteAction, moreAction]
    }

Xcode 项目改名

http://www.jianshu.com/p/bf151d0420ce

Xcode 9 感觉改名方便了很多

UITableView 单元格高度自适应

• http://www.hangge.com/blog/cache/detail_1341.html
• http://www.hangge.com/blog/cache/detail_1342.html
• http://www.hangge.com/blog/cache/detail_1343.html

使用 SnapKit 可以比较容易实现。

基本思路就是固定距离边的长度，位置条件要给够。

动画结束回调以及动画不还原的方法

http://www.jianshu.com/p/a8c9671adb28

回调

animationGroup.delegate = self

func animationDidStop(_ anim: CAAnimation, finished flag: Bool) {
  // ...
}

不还原

// 动画结束后不删除动画，否则在回调中无法得到动画
anim.fillMode = kCAFillModeForwards
// 设置动画不还原
anim.isRemovedOnCompletion = false

MBProgressHUD 提示框 在 Swift 中使用

https://www.coderecord.cn/use-mbprogresshud-in-swift.html

http://www.jianshu.com/p/cd81bcdef64f

head up display

UIButton hold on 按住时事件

https://stackoverflow.com/questions/19225475/uibutton-with-hold-down-action-and-release-action

aButton.addTarget(self, action: Selector("HoldDown:"), forControlEvents: UIControlEvents.TouchDown)
aButton.addTarget(self, action: Selector("holdRelease:"), forControlEvents: UIControlEvents.TouchUpInside);

//target functions   
func HoldDown(sender:UIButton) {
    println("hold down")
}

func holdRelease(sender:UIButton) {
    println("hold release")
}

NavigationController - go back to previous controller

https://stackoverflow.com/questions/28760541/programmatically-go-back-to-previous-viewcontroller-in-swift

If you want to go back to the previous view controller

_ = navigationController?.popViewController(animated: true)

If you want to go back to the root view controller

_ = navigationController?.popToRootViewController(animated: true)

UICollectionViewCell 同时加圆角和阴影

http://qingqinghebiancao.github.io/2016/01/12/iOS%E5%BC%80%E5%8F%91%E5%B0%8F%E6%8A%80%E5%B7%A7/

https://stackoverflow.com/questions/13505379/adding-rounded-corner-and-drop-shadow-to-uicollectionviewcell

self.contentView.layer.cornerRadius = 2.0
self.contentView.layer.borderWidth = 1.0
self.contentView.layer.borderColor = UIColor.clear.cgColor
self.contentView.layer.masksToBounds = true

self.layer.shadowColor = UIColor.lightGray.cgColor
self.layer.shadowOffset = CGSize(width: 0, height: 2.0)
self.layer.shadowRadius = 2.0
self.layer.shadowOpacity = 1.0
self.layer.masksToBounds = false
self.layer.shadowPath = UIBezierPath(roundedRect: self.bounds, cornerRadius: self.contentView.layer.cornerRadius).cgPath

CGPath 获取上面的 CGPoints

https://stackoverflow.com/questions/12992462/how-to-get-the-cgpoints-of-a-cgpath

extension CGPath {

    func forEach( body: @convention(block) (CGPathElement) -> Void) {
        typealias Body = @convention(block) (CGPathElement) -> Void
        let callback: @convention(c) (UnsafeMutableRawPointer, UnsafePointer<CGPathElement>) -> Void = { (info, element) in
            let body = unsafeBitCast(info, to: Body.self)
            body(element.pointee)
        }
        print(MemoryLayout.size(ofValue: body))
        let unsafeBody = unsafeBitCast(body, to: UnsafeMutableRawPointer.self)
        self.apply(info: unsafeBody, function: unsafeBitCast(callback, to: CGPathApplierFunction.self))
    }


    func getPathElementsPoints() -> [CGPoint] {
        var arrayPoints : [CGPoint]! = [CGPoint]()
        self.forEach { element in
            switch (element.type) {
            case CGPathElementType.moveToPoint:
                arrayPoints.append(element.points[0])
            case .addLineToPoint:
                arrayPoints.append(element.points[0])
            case .addQuadCurveToPoint:
                arrayPoints.append(element.points[0])
                arrayPoints.append(element.points[1])
            case .addCurveToPoint:
                arrayPoints.append(element.points[0])
                arrayPoints.append(element.points[1])
                arrayPoints.append(element.points[2])
            default: break
            }
        }
        return arrayPoints
    }

    func getPathElementsPointsAndTypes() -> ([CGPoint],[CGPathElementType]) {
        var arrayPoints : [CGPoint]! = [CGPoint]()
        var arrayTypes : [CGPathElementType]! = [CGPathElementType]()
        self.forEach { element in
            switch (element.type) {
            case CGPathElementType.moveToPoint:
                arrayPoints.append(element.points[0])
                arrayTypes.append(element.type)
            case .addLineToPoint:
                arrayPoints.append(element.points[0])
                arrayTypes.append(element.type)
            case .addQuadCurveToPoint:
                arrayPoints.append(element.points[0])
                arrayPoints.append(element.points[1])
                arrayTypes.append(element.type)
                arrayTypes.append(element.type)
            case .addCurveToPoint:
                arrayPoints.append(element.points[0])
                arrayPoints.append(element.points[1])
                arrayPoints.append(element.points[2])
                arrayTypes.append(element.type)
                arrayTypes.append(element.type)
                arrayTypes.append(element.type)
            default: break
            }
        }
        return (arrayPoints,arrayTypes)
    }
}

CGFloat、CGPoint、CGSize和CGRect

http://www.cnblogs.com/chivas/archive/2012/05/16/2504006.html

https://developer.apple.com/documentation/coregraphics/cggeometry

CGFloat: 浮点值的基本类型
CGPoint: 表示一个二维坐标系中的点
CGSize: 表示一个矩形的宽度和高度
CGRect: 表示一个矩形的位置和大小

typedef float CGFloat;// 32-bit
typedef double CGFloat;// 64-bit

struct CGPoint {
    CGFloat x;
    CGFloat y;
};
typedef struct CGPoint CGPoint;

struct CGSize {
    CGFloat width;
    CGFloat height;
};
typedef struct CGSize CGSize;

struct CGRect {
    CGPoint origin;
    CGSize size;
};
typedef struct CGRect CGRect;

注意：CGRect数据结构的高度和宽度可以是负数。例如，一个矩形的原点是[0.0，0.0]和大小是[10.0,10.0]。这个矩形完全等同原点是[10.0，10.0]和大小是[-10.0，-10.0]的矩形。

UILable 属性 自动换行 居中显示

http://blog.csdn.net/ios_db/article/details/17225315

//文字居中显示
label.textAlignment = UITextAlignmentCenter;
//自动折行设置
label.lineBreakMode = UILineBreakModeWordWrap;
label.numberOfLines = 0;

经纬度位置坐标与真实地理位置相互转化

http://www.hangge.com/blog/cache/detail_785.html

UITableView 属性设置

注册 cell

self.register(UITableViewCell.self, forCellReuseIdentifier: "dialogue_cell")

动态高度

self.estimatedRowHeight = 44.0;
self.rowHeight = UITableViewAutomaticDimension

去除分割线

self.separatorStyle = .none

手势 - Gesture Recognizer

        // 单击
        let tapGesture = UITapGestureRecognizer(target: self, action: #selector(dismissClose))
        tapGesture.require(toFail: doubleTapGesture)

UITapGestureRecognizer - 传值

https://stackoverflow.com/questions/38445262/pass-parameter-with-uitapgesturerecognizer

class ViewController: UIViewController {

    @IBOutlet weak var label1: UILabel!
    @IBOutlet weak var image: UIImageView!

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        image.userInteractionEnabled = true;
        let tappy = MyTapGesture(target: self, action: #selector(self.tapped(_:)))
        image.addGestureRecognizer(tappy)
        tappy.title = "val"
    }

    func tapped(sender : MyTapGesture) {
        print(sender.title)
        label1.text = sender.title
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}

class MyTapGesture: UITapGestureRecognizer {
    var title = String()
}

Navigation bar show/hide

https://stackoverflow.com/questions/2926914/navigation-bar-show-hide

The Swift way to hide the navigation bar is:

self.navigationController?.setNavigationBarHidden(true, animated: true)

To show it:

self.navigationController?.setNavigationBarHidden(false, animated: true)

隐藏水平滚动条

scrollView.showsVerticalScrollIndicator = FALSE;
scrollView.showsHorizontalScrollIndicator = FALSE;

SnapKit 使用

http://www.hangge.com/blog/cache/detail_1097.html

storyboard 等分屏幕宽度

http://www.jianshu.com/p/62d7ec1c794b

按钮宽度相当，相距为 0，距边为 0

Codable encoding and decoding

http://www.jianshu.com/p/bdd9c012df15
https://developer.apple.com/documentation/foundation/archives_and_serialization/encoding_and_decoding_custom_types
https://medium.com/@sarunw/codable-in-swift-4-0-1a12e38599d8

struct Landmark: Codable {
    var name: String
    var foundingYear: Int
    var location: Coordinate
    var vantagePoints: [Coordinate]
    
    enum CodingKeys: String, CodingKey {
        case name = "title"
        case foundingYear = "founding_date"
        
        case location
        case vantagePoints
    }
}

String 2 Int

https://stackoverflow.com/questions/24115141/swift-converting-string-to-int

let myString = "556"
let myInt = Int(myString)

Xcode 快捷键

http://www.cnblogs.com/jys509/p/4358950.html

• 格式化 ctrl+a 全选->ctrl + i 格式化

NavigationBar 相关

let textAttributes = [NSAttributedStringKey.foregroundColor: UIColor.white]
        navigationController?.navigationBar.titleTextAttributes = textAttributes

Could not find a storyboard named 'Main' in bundle

https://stackoverflow.com/questions/19240054/could-not-find-a-storyboard-named-main-in-bundle

open the info.plist of your project and remove the selected row displayed in screenshot

Main storyboard file base name

UITableViewCell 重用机制避免重复显示方案

UITableViewCell 数据会重复显示，应该是和重用机制有关，待解决。

• http://blog.csdn.net/mr_rog/article/details/40891483
• http://www.jianshu.com/p/38b4d1efd2ee

strokeStart strokeEnd

http://www.cnblogs.com/HypeCheng/p/4172253.html

1 keyPath = strokeStart 动画的fromValue = 0，toValue = 1
表示从路径的0位置画到1 怎么画是按照清除开始的位置也就是清除0 一直清除到1 效果就是一条路径慢慢的消失

2 keyPath = strokeStart 动画的fromValue = 1，toValue = 0
表示从路径的1位置画到0 怎么画是按照清除开始的位置也就是1 这样开始的路径是空的（即都被清除掉了）一直清除到0 效果就是一条路径被反方向画出来

3 keyPath = strokeEnd 动画的fromValue = 0，toValue = 1
表示 这里我们分3个点说明动画的顺序 strokeEnd从结尾开始清除 首先整条路径先清除后2/3，接着清除1/3 效果就是正方向画出路径

4 keyPath = strokeEnd 动画的fromValue = 1，toValue = 0
效果就是反方向路径慢慢消失