键盘使 UIView 出现时速度变慢？

Question

我有一个操作允许我呈现 ModalViewController 并将 UITextField 显示为第一响应者，问题是当此 ModalViewController 出现时需要一点时间，原因是键盘，当我将代码抓取到 viewDidAppear 时键盘需要一点时间才能显示，那么我怎样才能让 UIViewController 快速出现呢？

- (IBAction)goToModalViewController
{    
    ModalSearchViewController *msvc = [[ModalSearchViewController alloc] init];
    self.msvc.context = context;
    self.msvc.delegate = self;
    [self.msvc setModalTransitionStyle:UIModalTransitionStyleCrossDissolve ];                                                                                                                                                                                                                                                                                                                                                       
    [self presentModalViewController:msvc animated:YES];
}

ModalViewController 的 viewWillAppear：

- (void)viewWillAppear:(BOOL)animated
{
   [super viewWillAppear:YES];

   [findTextField becomeFirstResponder]; 
}

Answer 1

在 viewWillAppear 中尝试这样做。

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];

    //[findTextField becomeFirstResponder]; 
    [findTextField performSelector:@selector(becomeFirstResponder) withObject:nil afterDelay:0.3];
}