在Swift中传递数据有很多解决方案。

向前传递数据

我最喜欢的两种转发数据的方式是依赖注入（DI）和属性观察者

依赖注入

class CustomView : UIView {
    init(_ with model : Model) {
        // Do what you want with data
    }
}

财产观察员

class CustomView : UIView {
    var model : Model? {
        didSet {
            // Do what you want with data after assign data to model
        }
        willSet {
            // Do what you want with data before assign data to model
        }
    }
}

向后传递数据

还喜欢将数据传递到上一个VC/视图的方法：

协议和代表

protocol CustomViewDelegate : class {
    func addItemViewController(_ with data: Model?)
}

weak var delegate : CustomViewDelegate?

class AnotherCustomView: UIView {

     let customView = AnotherCustomView()

     init() {
         customView.delegate = self
     }
}

extention AnotherCustomView : CustomViewDelegate {
    func addItemViewController(_ with data: Model?) {
        // Do what you want with data
    }
}

关闭

class AnotherCustomView : UIView {
     init(addItem: @escaping (_ value : Model?) -> ()) {
        // Do what you want with data
     }
}

class CustomView : UIView {

    init() {
        let customView = AnotherCustomView { [weak self] model in
            // Do what you want with data
        }
    }
}

iOS中不同的类可以通过各种方式接收数据。例如-

在分配另一个类后直接初始化。委派-用于传回数据通知-用于在同一时间向多个类广播数据保存在NSUserDefaults中-用于以后访问Singleton类数据库和其他存储机制，如p-list文件等。

但是，对于将值传递给在当前类中完成分配的不同类的简单场景，最常见和首选的方法是在分配后直接设置值。具体操作如下：

我们可以使用两个控制器来理解它——Controller1和Controller2

假设在Controller1类中，您想要创建Controller2对象，并使用传递的String值推送它。可以这样做：

- (void)pushToController2 {

    Controller2 *obj = [[Controller2 alloc] initWithNib:@"Controller2" bundle:nil];
    [obj passValue:@"String"];
    [self pushViewController:obj animated:YES];
}

在Controller2类的实现中，该函数如下：

@interface Controller2  : NSObject

@property (nonatomic, strong) NSString* stringPassed;

@end

@implementation Controller2

@synthesize stringPassed = _stringPassed;

- (void) passValue:(NSString *)value {

    _stringPassed = value; // Or self.stringPassed = value
}

@end

您还可以按如下类似方式直接设置Controller2类的财产：

- (void)pushToController2 {

    Controller2 *obj = [[Controller2 alloc] initWithNib:@"Controller2" bundle:nil];
    [obj setStringPassed:@"String"];
    [self pushViewController:obj animated:YES];
}

要传递多个值，可以使用多个参数，如：

Controller2 *obj = [[Controller2 alloc] initWithNib:@"Controller2" bundle:nil];
[obj passValue:@“String1” andValues:objArray withDate:date];

或者，如果需要传递三个以上与公共特征相关的参数，则可以将这些值存储在模型类中，然后将该modelObject传递给下一个类

ModelClass *modelObject = [[ModelClass alloc] init];
modelObject.property1 = _property1;
modelObject.property2 = _property2;
modelObject.property3 = _property3;

Controller2 *obj = [[Controller2 alloc] initWithNib:@"Controller2" bundle:nil];
[obj passmodel: modelObject];

总之，如果你想-

设置第二类的私有变量通过调用自定义函数并传递值来初始化值。setProperties通过使用setter方法直接初始化它来实现。以某种方式传递超过3-4个彼此相关的值，然后创建一个模型类并将值设置到其对象，然后使用上述过程传递该对象。

新闻视图控制器

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
  [tbl_View deselectRowAtIndexPath:indexPath animated:YES];
  News *newsObj = [newstitleArr objectAtIndex:indexPath.row];
  NewsDetailViewController *newsDetailView = [[NewsDetailViewController alloc] initWithNibName:@"NewsDetailViewController" bundle:nil];

  newsDetailView.newsHeadlineStr = newsObj.newsHeadline;

  [self.navigationController pushViewController:newsDetailView animated:YES];
}

NewsDetailViewController.h

@interface NewsDetailViewController : UIViewController
@property(nonatomic,retain) NSString *newsHeadlineStr;
@end

NewsDetailViewController.m

@synthesize newsHeadlineStr;

这不是这样做的。你应该使用委托。

我假设我们有两个视图控制器，ViewController1和ViewController2，这个检查是在第一个视图控制器中，当它的状态发生变化时，您需要在ViewController2中执行一些操作。为了以正确的方式实现这一点，您应该执行以下操作：

向项目添加新文件（Objective-C协议）菜单文件→ 新现在将其命名为ViewController1Delegate或任何您想要的名称，并在@interface和@end指令之间编写这些命令：

@optional

- (void)checkStateDidChange:(BOOL)checked;

现在转到ViewController2.h并添加：

#import "ViewController1Delegate.h"

然后将其定义更改为：

@interface ViewController2: UIViewController<ViewController1Delegate>

现在转到ViewController2.m，在实现中添加：

- (void)checkStateDidChange:(BOOL)checked {
     if (checked) {
           // Do whatever you want here
           NSLog(@"Checked");
     }
     else {
           // Also do whatever you want here
           NSLog(@"Not checked");
     }
}

现在转到ViewController1.h并添加以下属性：

@property (weak, nonatomic) id<ViewController1Delegate> delegate;

现在，如果您在某个事件后在ViewController2内创建ViewController1，那么您应该使用NIB文件这样做：

ViewController1* controller = [[NSBundle mainBundle] loadNibNamed:@"ViewController1" owner:self options:nil][0];
controller.delegate = self;
[self presentViewController:controller animated:YES completion:nil];

现在你都准备好了。每当您检测到ViewController1中的检查事件发生更改时，您只需执行以下操作：

[delegate checkStateDidChange:checked]; // You pass here YES or NO based on the check state of your control

使用通知中心

对于Swift 3

let imageDataDict:[String: UIImage] = ["image": image]

// Post a notification
NotificationCenter.default.post(name: NSNotification.Name(rawValue: "notificationName"), object: nil, userInfo: imageDataDict)
// `default` is now a property, not a method call

// Register to receive notification in your class
NotificationCenter.default.addObserver(self, selector: #selector(self.showSpinningWheel(_:)), name: NSNotification.Name(rawValue: "notificationName"), object: nil)

// Handle notification
func showSpinningWheel(_ notification: NSNotification) {
    print(notification.userInfo ?? "")
    if let dict = notification.userInfo as NSDictionary? {
        if let id = dict["image"] as? UIImage {
            // Do something with your image
        }
    }
}

对于Swift 4

let imageDataDict:[String: UIImage] = ["image": image]

// Post a notification
NotificationCenter.default.post(name: NSNotification.Name(rawValue: "notificationName"), object: nil, userInfo: imageDataDict)
// `default` is now a property, not a method call

// Register to receive notification in your class
NotificationCenter.default.addObserver(self, selector: #selector(self.showSpinningWheel(_:)), name: NSNotification.Name(rawValue: "notificationName"), object: nil)

// Handle notification
@objc func showSpinningWheel(_ notification: NSNotification) {
    print(notification.userInfo ?? "")
    if let dict = notification.userInfo as NSDictionary? {
        if let id = dict["image"] as? UIImage {
            // Do something with your image
        }
    }
}

如果您想将数据从一个viewController发送到另一个viewController，请使用以下方法：

假设我们有viewControllers:viewControllerA和viewControllerB

现在在文件视图ControllerB.h中

@interface viewControllerB : UIViewController {

  NSString *string;
  NSArray *array;

}

- (id)initWithArray:(NSArray)a andString:(NSString)s;

在文件视图ControllerB.m中：

#import "viewControllerB.h"

@implementation viewControllerB

- (id)initWithArray:(NSArray)a andString:(NSString)s {

   array = [[NSArray alloc] init];
   array = a;

   string = [[NSString alloc] init];
   string = s;

}

在文件视图ControllerA.m中：

#import "viewControllerA.h"
#import "viewControllerB.h"

@implementation viewControllerA

- (void)someMethod {

  someArray = [NSArray arrayWithObjects:@"One", @"Two", @"Three", nil];
  someString = [NSString stringWithFormat:@"Hahahahaha"];

  viewControllerB *vc = [[viewControllerB alloc] initWithArray:someArray andString:someString];

  [self.navigationController pushViewController:vc animated:YES];
  [vc release];
}

因此，这就是在不设置任何委托的情况下将数据从viewControllerA传递到viewControllerB的方法。；）