如何在SWIFT中实现Objective-C回调处理程序？ [英] How to implement Objective-C callback handler in SWIFT?

问题描述

目标c代码如下所示：

   - （void）signInAccountWithUserName：（NSString *）userName 
密码：（NSString *）密码
 completion：（void（^）（BOOL success））completionBlock 
 {
 //使用`userName`和`password` 
 // BOOL loginSuccessful = [LoginManager contrivedLoginMethod]; 
 
 //注意，我们将BOOL传递回完成块。 
 if（completionBlock！= nil）completionBlock（loginSuccessful）; 
} 
  

，此方法的用法是：

  [self signInAccountWithUserName：@Bob
 password：@BobsPassword
 completion：^（BOOL success）{
 if成功）{
 [self displayBalance]; 
} else {
 //无法登录。向用户显示警报。 
} 
}]; 
  

如何在Swift中实现它？

$

  func signInAccount（用户名：NSString !,密码： NSString !, completionBlock：（（Bool） - >（））？）{
 if completionBlock {
 completionBlock！（true）
} 
} 
 
 signInAccount（Bob，BobPassword）{
（var success）in 
 println（\（success））
}; 
 
 signInAccount（Bob，BobPassword，nil）
  

The objective c code seems like this:

- (void)signInAccountWithUserName:(NSString *)userName
                         password:(NSString *)password
                       completion:(void (^)(BOOL success))completionBlock
{
    // Log into the account with `userName` and `password`...
    // BOOL loginSuccessful = [LoginManager contrivedLoginMethod];

    // Notice that we are passing a BOOL back to the completion block.
    if (completionBlock != nil) completionBlock(loginSuccessful);
}

and this method usage is:

[self signInAccountWithUserName:@"Bob"
                       password:@"BobsPassword"
                     completion:^(BOOL success) {
                         if (success) {
                             [self displayBalance];
                         } else {
                             // Could not log in. Display alert to user.
                         }
                     }];

How can I implement it in Swift? What is the equivalent implementation?

解决方案

func signInAccount(username:NSString!, password:NSString!, completionBlock:((Bool)->())?) {
    if completionBlock {
        completionBlock!(true)
    }
}

signInAccount("Bob", "BobPassword") {
    (var success) in
    println("\(success)")
};

signInAccount("Bob", "BobPassword", nil)

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