Question

我正在开发一个涉及iOS EventKit的项目。它需要向后兼容ios 5.所以我尝试了在SO上实现的几种方法。当我试图展示UIAlert时，它会崩溃。

-(void)addToCalender {

    EKEventStore *eventStore = [[EKEventStore alloc] init];

    if ([eventStore respondsToSelector:@selector(requestAccessToEntityType:completion:)])
    {
        __block typeof (self) weakSelf = self; // replace __block with __weak if you are using ARC
        [eventStore requestAccessToEntityType:EKEntityTypeEvent completion:^(BOOL granted, NSError *error)
         {
             if (granted)
             {
                 //[weakSelf performSelectorOnMainThread:@selector(addEventToCalendar) withObject:nil waitUntilDone:YES];
                 [weakSelf performSelectorOnMainThread: @selector(presentEventEditViewControllerWithEventStore:) withObject:eventStore waitUntilDone:YES];
             }
             else
             {
                 NSLog(@"Not granted");
                 UIAlertView *alert = [[UIAlertView alloc]
                                       initWithTitle: @"Announcement"
                                       message: @"It turns out that you are playing Addicus!"
                                       delegate: nil
                                       cancelButtonTitle:@"OK"
                                       otherButtonTitles:nil];
                 [alert show];
                 [alert release];
             }
         }];
    }
    else
    {
        [self performSelectorOnMainThread: @selector(presentEventEditViewControllerWithEventStore:) withObject:eventStore waitUntilDone:NO];
    }
}

我的错误信息相当模糊，但我猜它是关于无法解雇的主要问题的事情？

我不确定。但是，如果没有设置权限，我还想获得“此应用程序需要您的权限”对话框，这可能吗？

Answer 1

感谢Allocating/showing a UIAlertView in a Block statement

dispatch_async(dispatch_get_main_queue(), ^{
  UIAlertView *myAlert = [[[UIAlertView alloc]initWithTitle:@"Calendar Access Denied"
                                                    message:@"Een tekst"
                                                   delegate:nil
                                          cancelButtonTitle:@"OK"
                                          otherButtonTitles:nil] autorelease];
  [myAlert show];
});

我的假设是对的，需要在主线程

发送

Answer 2

我遇到了同样的问题。我使用了以下代码。请在此处使用您的代码。

dispatch_async(dispatch_get_main_queue(), ^{
    });

例如，

dispatch_async(dispatch_get_main_queue(), ^{
            // alert code
            UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Warning!" message:@"Your internet connection is currently unavailable. Please try to connect later." delegate:self cancelButtonTitle:@"Done" otherButtonTitles:nil];
            [alert show];
            [alert release];
        });

无法在EKEventStore中显示Alertview

2 个答案: