Question

我在ViewController中创建了一个 UIActionSheet 。我还添加了代码来捕获 UIKeyboardWillShowNotification 和 UIKeyboardWillHideNotification 通知。

我的问题是当我解雇时，我得到两个通知键盘隐藏并再次显示。有人可以告诉我如何预防这个问题？它只发生在iOS 7中并使用SDK 7构建

更新一些代码：

在viewDidLoad中，我初始化一个按钮，当触摸按钮时，将显示动作表。

- (void)viewDidLoad
{
    [super viewDidLoad];

    UIButton* button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    button.frame = CGRectMake(10, 50, 100, 30);
    [button setTitle:@"Open menu" forState:UIControlStateNormal];
    [button addTarget:self action:@selector(buttonTouched) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:button];

    UITextView* textView = [[UITextView alloc] initWithFrame:CGRectMake(0, 0, 100, 40)];
    [self.view addSubview:textView];
    [textView becomeFirstResponder];

    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(keyboardWillHide:)
                                                 name:UIKeyboardWillHideNotification
                                               object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(keyboardWillShow:)
                                                 name:UIKeyboardWillShowNotification
                                               object:nil];
}

- (void)searchBarCancelButtonClicked:(UISearchBar *) searchBar{
    [searchBar resignFirstResponder];
}

- (void) buttonTouched{
    UIActionSheet* actionSheet = [[UIActionSheet alloc] initWithTitle:@"Action sheet" delegate:self cancelButtonTitle:@"Cancel" destructiveButtonTitle:@"Destructive" otherButtonTitles:@"Hello", nil];
    [actionSheet showInView:self.view];
}

- (void)keyboardWillShow:(NSNotification*)notification{
    NSLog(@"keyboardWillShow");
}

- (void)keyboardWillHide:(NSNotification*)notification{
    NSLog(@"keyboardWillHide");
}

我运行app，键盘会显示，我触摸按钮，动作表显示。我通过触摸任何按钮关闭动作表，然后记录打印：

keyboardWillShow

keyboardWillHide

keyboardWillShow

Answer 1

有一个非常简单的解决方案。应该在控制器的.m文件中添加私有本地类别

@interface UIActionSheet (NonFirstResponder)
@end

@implementation UIActionSheet (NonFirstResponder)
- (BOOL)canBecomeFirstResponder
{
    return NO;
}
@end

它只有一个副作用。您的texField / textView在活动表演示期间保持关注。但我认为这不是一个大麻烦。

也可以用同样的方式继承 UIActionSheet 。

Answer 2

工作正常。

- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField{
    if(textField==myTextField2){
        [myTextField1 resignFirstResponder];
        [self showActionSheet];
        return NO;
    }
    return YES;      
}

在iOS 7，SDK 7中UIActionSheet解除后，键盘隐藏并再次显示

2 个答案: