如何通过iOS获得UIKeyboard尺寸

Question

有没有办法以编程方式获得UIKeyboard大小.高度216.0f,景观高度162.0f.

以下似乎已被弃用.有没有什么方法可以在3.0 iPhone OS SDK和4.0 iPhone OS SDK中都没有任何警告来执行此操作.

CGSize keyBoardSize = [[[note userInfo]
                        objectForKey:UIKeyboardBoundsUserInfoKey] CGRectValue].size;

Answer 1

您可以userInfo使用UIKeyboardFrameBeginUserInfoKey和UIKeyboardFrameEndUserInfoKey从字典中获取键盘大小.

这两个键返回一个NSValue实例,其中包含CGRect键盘在显示/隐藏动画的起点和终点的位置和大小.

编辑:

为了澄清,userInfo字典来自NSNotification实例.它传递给您向观察者注册的方法.例如,

- (void)someMethodWhereYouSetUpYourObserver
{
    // This could be in an init method.
    [[NSNotificationCenter defaultCenter] addObserver:self 
                    selector:@selector(myNotificationMethod:) 
                    name:UIKeyboardDidShowNotification 
                    object:nil];
}

- (void)myNotificationMethod:(NSNotification*)notification
{
    NSDictionary* keyboardInfo = [notification userInfo];
    NSValue* keyboardFrameBegin = [keyboardInfo valueForKey:UIKeyboardFrameBeginUserInfoKey];
    CGRect keyboardFrameBeginRect = [keyboardFrameBegin CGRectValue];
}

编辑2:

此外,请不要忘记在您的dealloc方法中删除自己作为观察者!这是为了避免通知中心在释放后通知您的对象时发生的崩溃.

Answer 2

您应该使用UIKeyboardWillChangeFrameNotification相反的,因为一些国际键盘,如中文键盘,将在使用过程中更改帧.还要确保将其CGRect转换为适当的视图,以供横向使用.

//some method like viewDidLoad, where you set up your observer.
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillChange:) name:UIKeyboardWillChangeFrameNotification object:nil];

- (void)keyboardWillChange:(NSNotification *)notification {
    CGRect keyboardRect = [notification.userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue];
    keyboardRect = [self.view convertRect:keyboardRect fromView:nil]; //this is it!
}