将uiactionsheet选项连接到操作的正确方法

我喜欢这边

- (void)actionSheet:(UIActionSheet *)actionSheet didDismissWithButtonIndex:(NSInteger)buttonIndex {
    if (buttonIndex == [actionSheet cancelButtonIndex]) 
    {
       // cancelled, nothing happen
       return;
    }

    // obtain a human-readable option string
    NSString *option = [actionSheet buttonTitleAtIndex:buttonIndex];
    if ([option isEqualToString:@"Twitter"])
    {
        //...
    } else if ([option isEqualToString:@"FaceBook"])
    {
        //...
    }
}

我完全同意这个问题。苹果在这里的设计鼓励使用神奇的数字,我有点惊讶地看到所有的解决方案都建议使用硬编码的数字作为按钮索引。

这是我对斯威夫特的解决方案。

• 为每个按钮标题创建一个包含项的枚举,例如:

enum ImagePickerActionSheetButtons
{
    case Camera
    case Chooser
}

使用每个按钮标题的本地化字符串填充字典,其中键是枚举中的项:

// Populate with LOCALIZED STRINGS
var buttonTitles:[ImagePickerActionSheetButtons:String] =
[ImagePickerActionSheetButtons.Camera:"Take photo",
    ImagePickerActionSheetButtons.Chooser :"Choose photo"]

创建操作表,按枚举值从字典中获取按钮标题:

func createActionSheet()->UIActionSheet
{
    var sheet: UIActionSheet = UIActionSheet()

    sheet.addButtonWithTitle(buttonTitles[.Camera]!)
    sheet.addButtonWithTitle(buttonTitles[.Chooser]!)

    sheet.addButtonWithTitle("Cancel")
    sheet.cancelButtonIndex = sheet.numberOfButtons - 1
    sheet.delegate = self
    return sheet
}

最后,在ClickedButtonatindex代码中,对照字典中的本地化字符串检查单击按钮的标题:

func actionSheet(sheet: UIActionSheet!, clickedButtonAtIndex buttonIndex: Int)
{
    if (sheet.buttonTitleAtIndex(buttonIndex) == buttonTitles[.Camera]!)
    {
        takePhoto()
    }
    else if (sheet.buttonTitleAtIndex(buttonIndex) == buttonTitles[.Chooser]!)
    {
        choosePicFromLibrary()
    }
    else if (buttonIndex == sheet.cancelButtonIndex)
    {
        // do nothing
    }
}

也许你可以把按钮的操作放到一个数组中

actionsArray = [NSMutableArray arrayWithObjects: @selector(btn1Clicked),    
                                    @selector(btn2Clicked), 
                                    @selector(btn3Clicked), 
                                    @selector(btn4Clicked), nil];

然后在迪迪米西斯威特百宁地塞米塞米塞米塞米塞米塞米塞米塞米塞米塞米塞米塞米塞米塞米塞米塞米塞米塞米塞米塞米塞米塞米塞米塞米塞米

-(void)actionSheet:(UIActionSheet *)actionSheet didDismissWithButtonIndex:(NSInteger)buttonIndex {
    if (buttonIndex == [actionSheet cancelButtonIndex]) {
        // all done
    } else {
       [this [actionsArray objectAtIndex: buttonIndex]];
    }
}

我很确定您可以在数组中放置一个更复杂的对象,包括按钮信息和方法,然后将其全部包含在数组中。最好检查数组的索引…等等。

老实说,在我读到这个问题之前,我从来没有想过这个模式,所以这只是我的想法而已。

那个怎么样?

通过这种方式,您不必担心索引,因为按钮和操作是在同一位置添加的。

typedef void (^contact_callback_t)(MyContactsController *controller);
 … 
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
     NSDictionary *contact = [myContacts objectAtIndex:indexPath.row];     
     UIActionSheet *_actionSheet = [[UIActionSheet alloc] initWithTitle:NSLocalizedString(@"Contact Action", @"")
                                                          delegate:self
                                                 cancelButtonTitle:nil
                                            destructiveButtonTitle:nil
                                                 otherButtonTitles:nil];

 _actions = [NSMutableArray new];
 if([contact objectForKey:@"private_email"] != nil) {
     [_actionSheet addButtonWithTitle:
      [NSString stringWithFormat:NSLocalizedString(@"E-Mail: %@", @""), [contact objectForKey:@"private_email"] ] ];
     contact_callback_t callback = ^(MyContactsController *controller) {
         [controller openEmail:contact];
     };
     [_actions addObject:callback];
 }
 if([contact objectForKey:@"private_telefon"] != nil) {
     [_actionSheet addButtonWithTitle: 
      [NSString stringWithFormat:NSLocalizedString(@"Phone: %@", @""), [contact objectForKey:@"private_telefon"] ]];
     contact_callback_t callback = ^(MyContactsController *controller) {
         [controller dial:[contact objectForKey:@"private_telefon"]];
     };
     [_actions addObject:callback];
   }
  [_actionSheet showFromTabBar:tabBar];     

}

- (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex 
{
  if(buttonIndex == actionSheet.cancelButtonIndex)
{
}
else
{
      contact_callback_t callback = [_actions objectAtIndex:buttonIndex];
      callback(self);
   }
  _actions = nil;
}

基于Aaron的选择建议,我非常喜欢现在做一个简单的特别调度方法的想法。它成功地避免了处理错误选项的可能性,并提供了一个清晰的关注因素分解。当然,我可以想象一个用例,在这个用例中,您希望首先为每个选项做一些其他的事情,比如实例化一个对象并将选项字符串传递给它,就像Toro的答案一样。

下面是一个简单的调度,它调用诸如“actionTwitter”等方法:

-(void)actionSheet:(UIActionSheet *)actionSheet didDismissWithButtonIndex:(NSInteger)buttonIndex {  
    if (buttonIndex == [actionSheet cancelButtonIndex]) {
        return;
    }

    NSString *methodName = [@"action" stringByAppendingString:[actionSheet buttonTitleAtIndex:buttonIndex]];
    SEL actionMethod = NSSelectorFromString(methodName);
    if ([self respondsToSelector:actionMethod]) {
        [self performSelector:actionMethod];
    } else {
        NSLog(@"Not yet implemented")
    }
}