在从UIActionSheet中按下按钮后调用方法时需要帮助

Question

我有一个能够从我的应用程序中的UIBarButtonItem成功调用的UIActionSheet。但是，当我单击UIActionSheet上的一个按钮时，我试图让它调用的方法似乎没有被调用，并且UIActionSheet消失了。我的相关代码如下所示：

在我的MapViewController.h文件中：

@interface MapViewController : UIViewController<MKMapViewDelegate, UIActionSheetDelegate>{

在我的MapViewController.m文件中：

-(IBAction)showActionSheet {
UIActionSheet *actionSheet = [[UIActionSheet alloc] initWithTitle:@"Share your favourite restaurant with your friends" delegate:nil cancelButtonTitle:@"Cancel" destructiveButtonTitle:nil otherButtonTitles:@"EMail",@"Facebook",@"Twitter",nil];
[actionSheet showInView:self.view];
[actionSheet release];
}

-(void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex {
if(buttonIndex == 0)
    NSLog(@"You chose email!");
if(buttonIndex == 1)
    NSLog(@"You chose facebook!");
if(buttonIndex == 2)
    NSLog(@"You chose twitter!");
}

有没有人能看到我哪里出了问题？我个人的预感是，这可能与我实现UIActionSheetDelegate接口的方式有关。

Answer 1

UIActionSheet *actionSheet = [[UIActionSheet alloc] initWithTitle:@"Share your favourite restaurant with your friends" delegate:nil cancelButtonTitle:@"Cancel" destructiveButtonTitle:nil otherButtonTitles:@"EMail",@"Facebook",@"Twitter",nil];

应该是

UIActionSheet *actionSheet = [[UIActionSheet alloc] initWithTitle:@"Share your favourite restaurant with your friends" delegate:self cancelButtonTitle:@"Cancel" destructiveButtonTitle:nil otherButtonTitles:@"EMail",@"Facebook",@"Twitter",nil];

还要确保您的.h文件实现UIActionSheetDelegate协议

Answer 2

您正在传递nil作为代理，但该代理是您的视图控制器，因此传递self：

UIActionSheet *actionSheet = [[UIActionSheet alloc] initWithTitle:@"Share your favourite restaurant with your friends" delegate:self cancelButtonTitle:@"Cancel" destructiveButtonTitle:nil otherButtonTitles:@"EMail",@"Facebook",@"Twitter",nil];

Answer 3

可能是您忘记设置委托，请在代码中添加以下内容

actionSheet.delegate = self ;

从文档中... 接收器的委托，如果它没有委托，则为nil。

@property(nonatomic, assign) id<UIActionSheetDelegate> delegate