ios - 键盘在 UIViewController Xamarin IOS 中隐藏 UITextView

Question

我创建了一个 UIViewController 并在 UIViewController 上放置了一个标签和 UITextView。

我想将一些 UITextView 放在我的 UIViewController 上，一个放在另一个下面。我仅在我的应用程序中使用横向模式。我正在使用 Xamarin IOS 来制作这个应用程序。

下面的屏幕显示了正在发生的事情!有人可以帮助我吗!

Answer 1

您需要在发生此问题的 View Controller 中添加观察者，如下所示。

ViewDidLoad() 的键盘观察器。

// Keyboard popup
NSNotificationCenter.DefaultCenter.AddObserver
(UIKeyboard.DidShowNotification,KeyBoardUpNotification);

// Keyboard Down
NSNotificationCenter.DefaultCenter.AddObserver
(UIKeyboard.WillHideNotification,KeyBoardDownNotification);

// Keyboard popup
NSNotificationCenter.DefaultCenter.AddObserver
(UIKeyboard.DidShowNotification,KeyBoardUpNotification);

// Keyboard Down
NSNotificationCenter.DefaultCenter.AddObserver
(UIKeyboard.WillHideNotification,KeyBoardDownNotification);

首先是 KeyboardUpNotification 方法。本质上，您计算控件是否会被键盘隐藏，如果是，则计算 View 需要移动多少才能显示控件，然后移动它。

private void KeyBoardUpNotification(NSNotification notification)
{
    // get the keyboard size
    RectangleF r = UIKeyboard.BoundsFromNotification (notification);

    // Find what opened the keyboard
    foreach (UIView view in this.View.Subviews) {
        if (view.IsFirstResponder)
            activeview = view;
    }

    // Bottom of the controller = initial position + height + offset      
    bottom = (activeview.Frame.Y + activeview.Frame.Height + offset);

    // Calculate how far we need to scroll
    scroll_amount = (r.Height - (View.Frame.Size.Height - bottom)) ;

    // Perform the scrolling
    if (scroll_amount > 0) {
         moveViewUp = true;
         ScrollTheView (moveViewUp);
    } else {
         moveViewUp = false;
    }

}

private void KeyBoardUpNotification(NSNotification notification)
{
    // get the keyboard size
    RectangleF r = UIKeyboard.BoundsFromNotification (notification);

    // Find what opened the keyboard
    foreach (UIView view in this.View.Subviews) {
        if (view.IsFirstResponder)
            activeview = view;
    }

    // Bottom of the controller = initial position + height + offset      
    bottom = (activeview.Frame.Y + activeview.Frame.Height + offset);

    // Calculate how far we need to scroll
    scroll_amount = (r.Height - (View.Frame.Size.Height - bottom)) ;

    // Perform the scrolling
    if (scroll_amount > 0) {
         moveViewUp = true;
         ScrollTheView (moveViewUp);
    } else {
         moveViewUp = false;
    }
}

事件字段用于跟踪当前启动的文本字段。

public override void EditingStarted (UITextField textField)
{
    activeview = textField;
}

了解更多:http://www.gooorack.com/2013/08/28/xamarin-moving-the-view-on-keyboard-show/