对UIAlertView进行子类化 [英] Subclassing UIAlertView

问题描述

尝试将UIAlertView子类化以更好地处理我的应用中的错误状态。我遇到的麻烦是使用 otherButtonTitles nil终止参数，当我创建我的子类时，它只是拾取列表中的第一个字符串而不是所有字符串

Am attempting to subclass UIAlertView to better handle error states in my app. The trouble am having is with the otherButtonTitles nil terminated parameter, when I create my subclass it is only picking up the first string in the list rather than all the strings

+ (ErrorAlertView *)displayErrorAlertViewWithTitle:(NSString *)title 
                                           message:(NSString *)message 
                                          delegate:(id<UIAlertViewDelegate>)delegate 
                                     errorDelegate:(id<ErrorAlertViewDelegate>)errorDelegate
                                 cancelButtonTitle:(NSString *)cancelButtonTitle 
                                        displayNow:(BOOL)displayNow
                                               tag:(NSUInteger)tag
                                 otherButtonTitles:(NSString *)otherButtonTitles, ...;

{

  ErrorAlertView *errorAlertView = [[ErrorAlertView alloc]  initWithTitle:title 
                                                                  message:message 
                                                                 delegate:delegate 
                                                        cancelButtonTitle:cancelButtonTitle 
                                                        otherButtonTitles:otherButtonTitles, nil];


  errorAlertView.errorDelegate = errorDelegate;
  errorAlertView.tag = tag;

  if (displayNow) {

    [errorAlertView show];

  }

  return [errorAlertView autorelease];


}

如果我进行以下调用以上方法：

If I make the following call the above method:

[ErrorAlertView displayErrorAlertViewWithTitle:[self noInternetConnectionAlertViewTitle] 
                                           message:[self noInternetConnectionAlertViewMessage] 
                                          delegate:self 
                                     errorDelegate:errorDelegate 
                                 cancelButtonTitle:@"OK" 
                                        displayNow:YES 
                                               tag:ErrorAlertTagInternetConnectionError 
                                 @"Try again",@"Setting", nil];

UIAlertView只显示@再试一次按钮。

The UIAlertView is being shown with only the @"Try again" button being shown.

推荐答案

你不能发送像这样的变量参数集。

You can't send a variable set of parameters like that.

我将UIAlertView子类化了我做了这个：

When I subclassed UIAlertView I did this:

va_list args;
va_start(args, otherButtonTitles);
for (NSString *anOtherButtonTitle = otherButtonTitles; anOtherButtonTitle != nil; anOtherButtonTitle = va_arg(args, NSString*)) {
    [self addButtonWithTitle:anOtherButtonTitle];
}

或者，您可以创建一个函数变体，接受va_list作为（单个）参数，然后运行上面的代码。

Alternatively, you could create a variant of your function that accepts a va_list as a (single) parameter, and then runs the above code.

通常，在编写可变参数函数时，应该包含一个替代方法来处理这种可能性。在这种情况下，Apple提供了addButtonWithTitle：方法。

Generally, when writing a variadic function, you should include an alternative for handling this eventuality. Apple supply the addButtonWithTitle: method in this case.

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