彈出一個UIAlertView，然后點(diǎn)擊窗口之外的區(qū)域來關(guān)閉UIALertView，代碼如下：

- (IBAction)showAlert:(id)sender {  
  
  alert = [[UIAlertView alloc] initWithTitle:@"測試"  
                                     message:@"點(diǎn)擊四周的區(qū)域我就消失"  
                                    delegate:nil  
                           cancelButtonTitle:@"確定"  
                           otherButtonTitles:nil];  
  [alert show];  
  recognizerTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTapBehind:)];  
  
  [recognizerTap setNumberOfTapsRequired:1];  
  recognizerTap.cancelsTouchesInView = NO;   
  [[UIApplication sharedApplication].keyWindow addGestureRecognizer:recognizerTap];  
}  
  
- (void)handleTapBehind:(UITapGestureRecognizer *)sender {  
  if (sender.state == UIGestureRecognizerStateEnded){  
    CGPoint location = [sender locationInView:nil];  
    if (![alert pointInside:[alert convertPoint:location fromView:alert.window] withEvent:nil]){  
      [alert.window removeGestureRecognizer:sender];  
      [alert dismissWithClickedButtonIndex:0 animated:YES];  
    }  
  }  
}