swift-oc和swift block和代理

一、闭包或block

1.1、swift 闭包表达式作为参数的形式

一、闭包的定义
func exec(v1: Int, v2: Int, fn: (Int, Int) -> Int) {
print(fn(v1, v2))
}
二、调用
exec(v1: 10, v2: 20, fn: {
(v1: Int, v2: Int) -> Int in
return v1 + v2 })

1.2、swift 闭包表达式作为属性

class Calculator {// 定义一个闭包属性，该闭包接受两个 Int 类型的参数并返回一个 Int 类型的值var addition: (Int, Int) -> Intinit(addition: @escaping (Int, Int) -> Int) {self.addition = addition}func performAddition(_ a: Int, _ b: Int) -> Int {return addition(a, b)}
}// 创建一个 Calculator 实例，并传入一个闭包表达式
let calculator = Calculator { (a, b) inreturn a + b
}// 使用闭包属性进行加法运算
let result = calculator.performAddition(5, 3)
print("5 + 3 = \(result)")    

1.3、oc 闭包表达式作为参数的形式

#import <Foundation/Foundation.h>// 定义一个带有block参数的函数
void performOperation(int a, int b, int (^operation)(int, int)) {int result = operation(a, b);NSLog(@"计算结果: %d", result);
}int main(int argc, const char * argv[]) {@autoreleasepool {// 定义一个blockint (^add)(int, int) = ^(int x, int y) {return x + y;};// 调用函数并传递blockperformOperation(5, 3, add);// 也可以直接传递匿名blockperformOperation(5, 3, ^(int x, int y) {return x * y;});}return 0;
}

1.4、oc 闭包表达式作为属性

#import <Foundation/Foundation.h>// 定义一个包含 block 属性的类
@interface MyClass : NSObject// 声明一个 block 属性
@property (nonatomic, copy) void (^myBlock)(NSString *);// 一个方法，用于调用 block
- (void)invokeBlockWithMessage:(NSString *)message;@end@implementation MyClass- (void)invokeBlockWithMessage:(NSString *)message {if (self.myBlock) {self.myBlock(message);}
}@endint main(int argc, const char * argv[]) {@autoreleasepool {// 创建 MyClass 实例MyClass *myObject = [[MyClass alloc] init];// 设置 block 属性myObject.myBlock = ^(NSString *message) {NSLog(@"接收到的消息: %@", message);};// 调用方法触发 block[myObject invokeBlockWithMessage:@"Hello, Block!"];}return 0;
}

二、代理

2.1、swift 代理表达式作为参数的形式

// 定义代理协议
protocol MyDelegate: AnyObject {func didSomething()
}// 一个类，接收代理作为参数
class MyClass {weak var delegate: MyDelegate?init(delegate: MyDelegate) {self.delegate = delegate}func performAction() {// 模拟执行某些操作print("Performing an action...")// 操作完成后调用代理方法delegate?.didSomething()}
}// 实现代理协议的类
class MyViewController: MyDelegate {func didSomething() {print("Delegate method called.")}
}// 使用示例
let viewController = MyViewController()
let myClass = MyClass(delegate: viewController)
myClass.performAction()

2.2、swift 代理表达式作为属性

定义协议
swift
protocol ButtonClickDelegate: AnyObject {func buttonDidClick()
}这里定义了一个协议 ButtonClickDelegate，声明了一个方法 buttonDidClick，表示按钮点击时要执行的操作。AnyObject 表明该协议只能被类遵循，结构体和枚举不能遵循。
创建视图控制器类并设置代理属性
swift
class ViewController: UIViewController {weak var buttonDelegate: ButtonClickDelegate?@IBAction func buttonTapped(_ sender: UIButton) {buttonDelegate?.buttonDidClick()}
}
在 ViewController 类中，定义了一个可选的、弱引用的代理属性 buttonDelegate，遵循 ButtonClickDelegate 协议。当按钮被点击时，调用代理的 buttonDidClick 方法。
创建另一个类遵循协议并实现方法
swift
class AnotherClass: ButtonClickDelegate {func buttonDidClick() {print("按钮被点击了！")}
}
AnotherClass 遵循 ButtonClickDelegate 协议，并实现了 buttonDidClick 方法，在方法中打印提示信息。
设置代理并测试
swift
let viewController = ViewController()
let another = AnotherClass()
viewController.buttonDelegate = another
// 模拟按钮点击（实际开发中由用户操作触发）
viewController.buttonTapped(UIButton()) 
通过设置 viewController 的 buttonDelegate 为 another，当按钮点击时，AnotherClass 中的 buttonDidClick 方法就会被调用。

2.3、oc 代理表达式作为参数的形式

#import <Foundation/Foundation.h>// 定义代理协议
@protocol DataLoaderDelegate <NSObject>// 数据加载成功的回调方法
- (void)dataLoaderDidFinishLoading:(NSData *)data;
// 数据加载失败的回调方法
- (void)dataLoaderDidFailWithError:(NSError *)error;@end// 数据加载器类
@interface DataLoader : NSObject// 加载数据的方法，接受代理对象作为参数
- (void)loadDataWithDelegate:(id<DataLoaderDelegate>)delegate;@end@implementation DataLoader- (void)loadDataWithDelegate:(id<DataLoaderDelegate>)delegate {// 模拟数据加载过程dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{// 模拟耗时操作sleep(2);// 模拟成功或失败BOOL success = arc4random_uniform(2) == 0;if (success) {// 模拟成功加载的数据NSData *data = [@"This is loaded data" dataUsingEncoding:NSUTF8StringEncoding];dispatch_async(dispatch_get_main_queue(), ^{[delegate dataLoaderDidFinishLoading:data];});} else {// 模拟加载失败的错误NSError *error = [NSError errorWithDomain:@"DataLoaderErrorDomain" code:1 userInfo:@{NSLocalizedDescriptionKey: @"Failed to load data"}];dispatch_async(dispatch_get_main_queue(), ^{[delegate dataLoaderDidFailWithError:error];});}});
}@end// 实现代理协议的类
@interface ViewController : NSObject <DataLoaderDelegate>- (void)startLoadingData;@end@implementation ViewController- (void)startLoadingData {DataLoader *loader = [[DataLoader alloc] init];[loader loadDataWithDelegate:self];
}- (void)dataLoaderDidFinishLoading:(NSData *)data {NSString *loadedString = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];NSLog(@"Data loaded successfully: %@", loadedString);
}- (void)dataLoaderDidFailWithError:(NSError *)error {NSLog(@"Data loading failed: %@", error.localizedDescription);
}@end// 主函数
int main(int argc, const char * argv[]) {@autoreleasepool {ViewController *vc = [[ViewController alloc] init];[vc startLoadingData];// 为了模拟异步操作，这里简单等待一段时间[[NSRunLoop currentRunLoop] runUntilDate:[NSDate dateWithTimeIntervalSinceNow:5]];}return 0;
}

2.4、oc 代理 闭包表达式作为属性

#import <Foundation/Foundation.h>// 定义代理协议
@protocol DownloadManagerDelegate <NSObject>@optional
// 下载完成的回调方法
- (void)downloadManagerDidFinishDownloading:(NSString *)filePath;
// 下载失败的回调方法
- (void)downloadManagerDidFailWithError:(NSError *)error;@end// 下载管理类
@interface DownloadManager : NSObject// 声明代理属性，使用 weak 修饰符避免循环引用
@property (nonatomic, weak) id<DownloadManagerDelegate> delegate;// 开始下载的方法
- (void)startDownloading;@end@implementation DownloadManager- (void)startDownloading {// 模拟下载过程dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{// 模拟耗时操作sleep(2);// 模拟成功或失败BOOL success = arc4random_uniform(2) == 0;if (success) {NSString *filePath = @"/path/to/downloaded/file";dispatch_async(dispatch_get_main_queue(), ^{if ([self.delegate respondsToSelector:@selector(downloadManagerDidFinishDownloading:)]) {[self.delegate downloadManagerDidFinishDownloading:filePath];}});} else {NSError *error = [NSError errorWithDomain:@"DownloadErrorDomain" code:1 userInfo:@{NSLocalizedDescriptionKey: @"Download failed"}];dispatch_async(dispatch_get_main_queue(), ^{if ([self.delegate respondsToSelector:@selector(downloadManagerDidFailWithError:)]) {[self.delegate downloadManagerDidFailWithError:error];}});}});
}@end// 实现代理协议的类
@interface ViewController : NSObject <DownloadManagerDelegate>- (void)startDownload;@end@implementation ViewController- (void)startDownload {DownloadManager *manager = [[DownloadManager alloc] init];manager.delegate = self;[manager startDownloading];
}- (void)downloadManagerDidFinishDownloading:(NSString *)filePath {NSLog(@"Download finished. File path: %@", filePath);
}- (void)downloadManagerDidFailWithError:(NSError *)error {NSLog(@"Download failed: %@", error.localizedDescription);
}@end// 主函数
int main(int argc, const char * argv[]) {@autoreleasepool {ViewController *vc = [[ViewController alloc] init];[vc startDownload];// 为了模拟异步操作，这里简单等待一段时间[[NSRunLoop currentRunLoop] runUntilDate:[NSDate dateWithTimeIntervalSinceNow:5]];}return 0;
}