如何将字符串数组发送到 UIActionSheet varargs init 方法中？

Question

我有一份行动表，其中的选项根据具体情况而有所不同。有足够多的不同按钮标题，我想首先构建这些按钮标题的数组，但我不知道如何将其转换为可变参数格式。

我想做这样的事情：

NSMutableArray *buttonTitles = [NSMutableArray array];
if (condition1) {
    [buttonTitles addObject: @"Do action 1"];
}
if (condition2) {
    [buttonTitles addObject: @"Do action 2"];
}
if (condition3) {
    [buttonTitles addObject: @"Do action 3"];
}
if (condition4) {
    [buttonTitles addObject: @"Do action 4"];
}
UIActionSheet *actionSheet = [[[UIActionSheet alloc] initWithTitle: nil delegate: self cancelButtonTitle: @"Cancel" destructiveButtonTitle: nil otherButtonTitles: buttonTitles] autorelease];

现在显然，如果我必须这样做，我可以做这样的事情：

UIActionSheet *actionSheet = nil;
if (condition1 && condition2 && condition3 && condition4) {
    actionSheet = [[[UIActionSheet alloc] initWithTitle: nil delegate: self cancelButtonTitle: @"Cancel" destructiveButtonTitle: nil otherButtonTitles: @"Do action1", @"Do action2", @"Do action3", @"Do action 4", nil] autorelease];    
} else if (condition1 && condition2 && condition3 && !condition4) {
    actionSheet = [[[UIActionSheet alloc] initWithTitle: nil delegate: self cancelButtonTitle: @"Cancel" destructiveButtonTitle: nil otherButtonTitles: @"Do action1", @"Do action2", @"Do action3", nil] autorelease];    
} 
// else ...
// about 14 other cases!

但这将是可怕的。有人知道一些不错的语法糖来帮助我吗？

编辑： 有人建议我使用 addButtonWithTitle，从表面上看，它看起来很棒，但不幸的是，它将附加按钮放在取消按钮之后，这是不可取的。

我相信这是苹果代码的错误，因为他们的 addButtonWithTitle 文档指出：

// adds a button with the title. returns the index (0 based) of where it was added. buttons are displayed in the order added except for the
// destructive and cancel button which will be positioned based on HI requirements. buttons cannot be customized.

HI 要求（苹果自己的人机界面指南）倾向于在所有其他选项下方使用取消按钮，所以我想说苹果搞砸了。当然，这并没有真正帮助我，所以我又开始尝试在 NSArray 和 varargs 之间进行转换，但我仍然不知道该怎么做。

Answer 1

你可以试试这个

NSMutableArray *buttonTitles = [NSMutableArray array];
if (condition1) {
    [buttonTitles addObject: @"Do action 1"];
}
if (condition2) {
    [buttonTitles addObject: @"Do action 2"];
}
if (condition3) {
    [buttonTitles addObject: @"Do action 3"];
}
if (condition4) {
    [buttonTitles addObject: @"Do action 4"];
}
[buttonTitles addObject: @"Cancel"];
UIActionSheet *actionSheet = [[[UIActionSheet alloc] initWithTitle: nil delegate: self cancelButtonTitle: nil destructiveButtonTitle: nil otherButtonTitles: nil] autorelease];

for (NSString *title in buttonTitles) {
    [actionSheet addButtonWithTitle: title];
}

[actionSheet setCancelButtonIndex: [buttonTitles count] - 1];

Answer 2

Himanshu 答案的一个变体：

    UIActionSheet * as = [[UIActionSheet alloc] initWithTitle:@"Share" 
                                                 delegate:self 
                                        cancelButtonTitle:nil /* don't set Cancel title here! */
                                   destructiveButtonTitle:nil 
                                        otherButtonTitles:nil];
int cancelButtonIndex = 0; // will remain 0 if no other buttons besides "Cancel"
if ( canShareBySMS )
{
    [as addButtonWithTitle:kSMSButtonText];
    cancelButtonIndex++;
}
if ( canShareByMail )
{
    [as addButtonWithTitle:kEmailButtonText];
    cancelButtonIndex++;
}
/* etc. */

// after all other buttons have been added, include Cancel
[as addButtonWithTitle:@"Cancel"];
[as setCancelButtonIndex:cancelButtonIndex];

[as showInView:self.sharingViewController.view];
[as release];

注意：你的 UIActionSheetDelegate 方法应该检查按钮标题而不是 buttonIndex：

- (void)actionSheet:(UIActionSheet *)actionSheet willDismissWithButtonIndex:(NSInteger)buttonIndex {
    if ([[actionSheet buttonTitleAtIndex:buttonIndex] isEqualToString:kSMSButtonText]) {
    //share via sms
    }else if ([[actionSheet buttonTitleAtIndex:buttonIndex] isEqualToString:kEmailButtonText]) {
    //share via mail
    }
}

我认为人们错过的关键细节是在 initWithTitle 选择器中设置 cancelButton，而不是在所有其他按钮之后添加它并指定外观通过调用 setCancelButtonIndex: 来取消按钮。

Answer 3

为什么不直接做这样的事情：

for (Nstring *button in buttonTitles)
  [actionSheet addButtonWithTitle:button];

Answer 4

这是我尝试过的一种方法，似乎效果很好。如果您想在按钮末尾、“取消”按钮之前添加一个附加按钮，则此方法有效。

NSString * optionalButton = nil;
if (condition4) {
  optionalButton = @"Some Additional Option";
}

UIActionSheet * actionSheet = [[UIActionSheet alloc] initWithTitle:@"Some Title" 
                                                          delegate:self 
                                                 cancelButtonTitle:@"Cancel" 
                                            destructiveButtonTitle:nil 
                                                 otherButtonTitles:@"Button 1",@"Button 2",@"Button 3",optionalButton, nil];


[actionSheet showInView:self.view];

如果不满足您的条件（条件 4），则可以在按钮列表末尾添加额外的“nil”。

我已经在iOS7上测试成功了。