iOS8 UIAlertView键盘闪一下的问题

 if (SYSTEM_VERSION >= 8.0) {
                     UIAlertController *alertCtrl = [UIAlertController alertControllerWithTitle:@"赎回成功" message:nil preferredStyle:UIAlertControllerStyleAlert];
                     UIAlertAction *okAction = [UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {
                         [self.navigationController popViewControllerAnimated:YES];
                     }];
                     [alertCtrl addAction:okAction];
                     [self presentViewController:alertCtrl animated:YES completion:nil];

                 }else{
                 //这个else一定要写，否则会导致在ios8一下的真机crash
                     UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"赎回成功" message:nil delegate:self cancelButtonTitle:nil otherButtonTitles:@"确定", nil];
                     alert.tag = ;
                     [alert show];
                 }

 #pragma mark-UIAlertViewDelegate
 -(void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
 {
     if (alertView.tag == ) {
         [self.navigationController popViewControllerAnimated:YES];
     }
 }

iOS 8 以后不用alertView了。使用UIAlertController代替。使用方法相同。