欢迎来到我的个人博客

Swift基础语法（五）

  • ~11.24K 字

一、纯代码创建应用根试图

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    
    // 创建UIWindow对象，并初始化该窗口的大小与主屏幕大小相同
    let rect : CGRect = UIScreen.main.bounds
    // 程序将创建的UIWindow对象赋值给该程序委托对象的window属性
    self.window = UIWindow(frame:rect)
    // 创建ViewController对象、并使用ViewController界面布局文件来
    // 初始化该视图控制器关联的用户界面
    let vc = ViewController()
    //通过控件加载视图
    //let vc = ViewController(nibName: "ViewController", bundle: nil)   bundle:nil];
    // 让该程序的窗口加载、并显示viewController视图控制器关联的用户界面
    self.window?.rootViewController = vc
    //设置背景颜色
    self.window?.backgroundColor = UIColor.white
    // 将该UIWindow对象设为主窗口、并显示出来
    self.window?.makeKeyAndVisible()
    return true
}

二、UILabel、UIButton、UIImageView的使用

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
  let mylabel = UILabel(frame:CGRect.init(x: 30, y: 100, width: 100, height: 30))
  mylabel.text = "标签"
  mylabel.backgroundColor = UIColor.orange
  mylabel.textColor = UIColor.black
  
  let but = UIButton.init(frame: CGRect.init(x: 30, y: 200, width: 50, height: 50))
  but.setTitle("按钮", for: .normal)
  but.backgroundColor = UIColor.gray
  but.addTarget(self, action: #selector(buttonClick(_:)), for: .touchUpInside)
  
  let imageV = UIImageView.init(frame: CGRect.init(x: 30, y: 300, width: 80, height: 80))
  imageV.image = UIImage.init(named: "xixi")
  
  let sc = UIScrollView.init(frame: CGRect.init(x: 0, y: 0, width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.height));
  sc.contentSize = CGSize.init(width: UIScreen.main.bounds.width, height: 1000)
  self.view.addSubview(sc)
  
  sc.addSubview(mylabel)
  sc.addSubview(but)
  sc.addSubview(imageV)

//  按钮的点击事件
@objc func buttonClick(_ button:UIButton) -> () {
      let butTitle:String = button.title(for: .normal)!
      print("按钮点击了: \(butTitle)")
  }

三、UITableView的使用

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
var myTb : UITableView?

override func viewDidLoad() {
    super.viewDidLoad()
    
    title = "Tb 测试"
    myTb = UITableView.init(frame: UIScreen.main.bounds)
    myTb?.dataSource = self
    myTb?.delegate = self
    myTb?.backgroundColor = UIColor.white
    view.addSubview((myTb)!)
    myTb?.tableFooterView = UIView()
}

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return 100
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
    return 60
}

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    
    let indentifier = "myCell"
    var cell:MyNewTableViewCell? = tableView.dequeueReusableCell(withIdentifier: indentifier) as? MyNewTableViewCell
    if cell == nil {
        //自定义cell使用此方法
        cell = MyNewTableViewCell(style: .subtitle, reuseIdentifier: "cellId")
        //xib加载cell使用此方法
        // cell = Bundle.main.loadNibNamed("testCell", owner: nil, options: nil)?.last as? UITableViewCell
    }
    cell?.label1?.text = "label1 :\(indexPath.row)"
    cell?.label2?.text = "label2 :\(indexPath.row)"
    return cell!
}

在Swift中，创建tableViewCell的方法可以分为两种创建tableView时候注册和需要使用时手动创建。先聊聊创建tableView的时候直接注册cell：

1
myTb?.register(MyNewTableViewCell.self, forCellReuseIdentifier: "myCell")

当注册了Cell之后，在没有可重用的Cell时会自动创建，并且不能在需要时手动创建。

1
2
3
4
5
6
7
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    //创建cell，不需要判断是否为空，当没有可重用cell的时候会自动创建
    let cell:MyNewTableViewCell = (tableView.dequeueReusableCell(withIdentifier: "myCell", for: indexPath) as? MyNewTableViewCell)!
    cell.label1?.text = "label1 :\(indexPath.row)"
    cell.label2?.text = "label2 :\(indexPath.row)"
    return cell
}

可以在自定义cell中处理点击状态下的显示

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
var label1 :UILabel?
var label2 :UILabel?

override init(style: UITableViewCellStyle, reuseIdentifier: String?) {
    
    super.init(style: style, reuseIdentifier: reuseIdentifier)
    
    label1 = UILabel.init(frame: CGRect.init(x: 20, y: 10, width: 80, height: 20))
    label2 = UILabel.init(frame: CGRect.init(x: 20, y: 30, width: 80, height: 20))
    contentView.addSubview(label1!)
    contentView.addSubview(label2!)
}

required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}

//点击情况下的显示处理
override func setSelected(_ selected: Bool, animated: Bool) {
    super.setSelected(selected, animated: animated)

    if selected == true {
        contentView.backgroundColor = UIColor.yellow
        DispatchQueue.main.asyncAfter(deadline: DispatchTime.now()+0.4) {
            self.contentView.backgroundColor = UIColor.white
        }
    }
   
}

四、UITabBarController的使用

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
 func rootTabbarViewController() -> UITabBarController {
    
    // 首页
    let vc01 = ViewController()
    vc01.title = "首页"
    let nav01 = UINavigationController(rootViewController: vc01)
    // 发现
    let vc02 = UIViewController()
    vc02.title = "发现"
    let nav02 = UINavigationController(rootViewController: vc02)
    
    // 设置标题，未选中状态图标，选中状态图标
    let barItem01 = UITabBarItem(title: nil, image: UIImage(named: "TabBarItem_nomal_0")?.withRenderingMode(.alwaysOriginal), selectedImage: UIImage(named: "TabBarItem_light_0")?.withRenderingMode(.alwaysOriginal))
    vc01.tabBarItem = barItem01
    let barItem02 = UITabBarItem(title: nil, image: UIImage(named: "TabBarItem_nomal_1")?.withRenderingMode(.alwaysOriginal), selectedImage: UIImage(named: "TabBarItem_light_1")?.withRenderingMode(.alwaysOriginal))
    vc02.tabBarItem = barItem02
    
    let tabbarController = UITabBarController()
    tabbarController.tabBar.barTintColor = UIColor.white
    // 注意：视图控制器超过5个时（不包含5）会自动生成一个more视图标签，用来控制第5、6、...以后的视图控制器。
    tabbarController.viewControllers = [nav01, nav02]
    // 属性设置
    // 设置默认被选中视图控制器
    tabbarController.selectedIndex = 0;
    // 设置切换视图 tabBar 属性
    // 1 打开用户交互
    tabbarController.tabBar.isUserInteractionEnabled = true;
    // 2 设置背景颜色
    tabbarController.tabBar.backgroundColor = UIColor.black
    tabbarController.tabBar.barTintColor = UIColor.white
    //        // 3 设置背景图片
    //        tabbarController.tabBar.backgroundImage = UIImage(named: "")
    //        // 4 选中时的背景图片
    //        tabbarController.tabBar.selectionIndicatorImage = UIImage(named: "")
    
    // 设置字体颜色
    UITabBarItem.appearance().setTitleTextAttributes([NSAttributedStringKey.foregroundColor: UIColor.gray], for: UIControlState.normal)
    UITabBarItem.appearance().setTitleTextAttributes([NSAttributedStringKey.foregroundColor: UIColor.green], for: UIControlState.selected)
    // 设置字体大小
    UITabBarItem.appearance().setTitleTextAttributes([NSAttributedStringKey.font: UIFont.systemFont(ofSize: 10.0)], for: UIControlState.normal)
    // 设置字体偏移
    //   UITabBarItem.appearance().titlePositionAdjustment = UIOffsetMake(0.0, -5.0)
    // 设置图标选中时颜色
    UITabBar.appearance().tintColor = UIColor.clear

    return tabbarController
}

这里特别说明下：默认未选中标签的图片和文字是灰色的，选中的是蓝色的，下面修改成橙色：

1
2
//图片文字一起变色
self.tabBar.tintColor = UIColor.orangeColor()

如何显示原始图片的颜色和图案？ .imageWithRenderingMode(.AlwaysOriginal) 即可。

五、单例

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
class AppManager {
private static let _sharedInstance = AppManager()
 
class func getSharedInstance() -> AppManager {
    return _sharedInstance
}
  private override init() {} // 私有化init方法
}

//使用方式
AppManager.getSharedInstance()

为什么需要保证INIT的私有化？ 
因为只有init()是私有的，才能防止其他对象通过默认构造函数直接创建这个类对象，确保你的单例是真正的独一无二。 
因为在Swift中，所有对象的构造器默认都是public，所以需要重写你的init让其成为私有的。
这样就保证像如下的代码编译报错，不能通过。

六、从相册选择照片或者拍照

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
import UIKit

class ViewController: UIViewController,UIImagePickerControllerDelegate,UINavigationControllerDelegate {
    
    var uploadAlertController : UIAlertController?
    var pick:UIImagePickerController?
    var imageV :UIImageView?
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        self.view.backgroundColor = UIColor.gray
        
        imageV = UIImageView.init(frame: CGRect.init(x: 30, y: 300, width: 80, height: 80))
        self.view.addSubview(imageV!)
        initAlertController()
        tapImage()
    }
    func initAlertController() {
        weak var blockSelf = self
        uploadAlertController = UIAlertController(title:nil, message: nil, preferredStyle:UIAlertControllerStyle.actionSheet)
        let takePhoto = UIAlertAction(title:"拍照", style:UIAlertActionStyle.default) { (action:UIAlertAction)in
            blockSelf?.actionAction(action: action)
        }
        let photoLib = UIAlertAction(title:"从相册选择", style:UIAlertActionStyle.default) { (action:UIAlertAction)in
            blockSelf?.actionAction(action: action)
        }
        let cancel = UIAlertAction(title:"取消", style:UIAlertActionStyle.cancel) { (action:UIAlertAction)in
            blockSelf?.actionAction(action: action)
        }
        uploadAlertController?.addAction(takePhoto)
        uploadAlertController?.addAction(photoLib)
        uploadAlertController?.addAction(cancel)
    }
  
    func tapImage(){
        present(uploadAlertController!, animated:true, completion: nil)
        initImagePickerController()
    }
  
    func initImagePickerController() {
        pick = UIImagePickerController()
        pick?.delegate = self
        // 设置是否可以管理已经存在的图片或者视频
        pick?.allowsEditing = true
    }
  
    func actionAction(action:UIAlertAction) {
        if action.title == "拍照" {
            self.getImageFromCamera(type: .camera)
        }else if action.title == "从相册选择" || action.title == "更换头像" {
            self.getImageFromPhotoLib(type: .photoLibrary)
        }
    }
  
    //拍照
    func getImageFromCamera(type:UIImagePickerControllerSourceType) {
        pick?.sourceType = type
        self.present(pick!, animated: true, completion:nil)
    }
  
    //相册选择
    func getImageFromPhotoLib(type:UIImagePickerControllerSourceType) {
        pick?.sourceType = type
        self.present(pick!, animated: true, completion:nil)
    }
  
    //MARK:- UIImagePickerControllerDelegate
    func imagePickerController(_ picker:UIImagePickerController, didFinishPickingMediaWithInfo info: [String :Any]){
        
        let type:String = (info[UIImagePickerControllerMediaType]as!String)
        //当选择的类型是图片
        if type == "public.image" {
            let img = info[UIImagePickerControllerOriginalImage]as?UIImage
            imageV?.image = img
        }
        picker.dismiss(animated:true, completion:nil)
    }
    
    func imagePickerControllerDidCancel(_ picker:UIImagePickerController){
        picker.dismiss(animated:true, completion:nil)
    }
}
本作品采用 知识共享署名-相同方式共享 4.0 国际许可协议 进行许可