设置UIAlertView委托

Question

我正在尝试使用此代码将viewcontroller A委托给viewcontroller B中的UIAlertView：

在ViewcontrollerA.m

中

-(IBAction)callCancelAlert:(id)sender{

ViewcontrollerB *controller = [[PhotoViewController alloc] init];

UIAlertView *alert = [[UIAlertView alloc]
                      initWithTitle: @"Announcement"
                      message: @"It turns out that you are playing Addicus!"
                      delegate: PhotoViewController
                      cancelButtonTitle:@"OK"
                      otherButtonTitles:nil];
[alert show];
//[alert release];
}

和#import ViewcontorllerB.h

...但我收到错误“意外的接口名称ViewcontorllerB：期望的表达式”。这是什么意思？

Answer 1

您的委托需要是ViewControllerB的实例，而不是类。

UIAlertView *alert = [[UIAlertView alloc]
                      initWithTitle: @"Announcement"
                      message: @"It turns out that you are playing Addicus!"
                      delegate: PhotoViewController
                      cancelButtonTitle:@"OK"
                      otherButtonTitles:nil];

到

UIAlertView *alert = [[UIAlertView alloc]
                      initWithTitle: @"Announcement"
                      message: @"It turns out that you are playing Addicus!"
                      delegate: controller
                      cancelButtonTitle:@"OK"
                      otherButtonTitles:nil];

Answer 2

您可能不是指delegate: PhotoViewController，这意味着“将委托设置为PhotoViewController类”。

相反，你可能想要这个：

UIAlertView *alert = [[UIAlertView alloc]
                  initWithTitle: @"Announcement"
                  message: @"It turns out that you are playing Addicus!"
                  delegate:controller
                  cancelButtonTitle:@"OK"
                  otherButtonTitles:nil];