Question

目标c代码如下所示：

- (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);
}

这个方法用法是：

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

如何在Swift中实现它？什么是等效实现？

Answer 1

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

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

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

Answer 2

这是你在swift中使用回调实现方法的方法。

func signInAccountWithUsername(userName:String!, password: String!, completion: (Bool) -> Void){

  completion(false)
}



signInAccountWithUsername("Swift", "secret swift", {
    success in

    if success{
      println("Success")
    }else{
      println("Failure")
    }
})

如何在SWIFT中实现Objective-C回调处理程序？

2 个答案: